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Linux/arch/x86/kernel/apm_32.c

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  1 /* -*- linux-c -*-
  2  * APM BIOS driver for Linux
  3  * Copyright 1994-2001 Stephen Rothwell (sfr@canb.auug.org.au)
  4  *
  5  * Initial development of this driver was funded by NEC Australia P/L
  6  *      and NEC Corporation
  7  *
  8  * This program is free software; you can redistribute it and/or modify it
  9  * under the terms of the GNU General Public License as published by the
 10  * Free Software Foundation; either version 2, or (at your option) any
 11  * later version.
 12  *
 13  * This program is distributed in the hope that it will be useful, but
 14  * WITHOUT ANY WARRANTY; without even the implied warranty of
 15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 16  * General Public License for more details.
 17  *
 18  * October 1995, Rik Faith (faith@cs.unc.edu):
 19  *    Minor enhancements and updates (to the patch set) for 1.3.x
 20  *    Documentation
 21  * January 1996, Rik Faith (faith@cs.unc.edu):
 22  *    Make /proc/apm easy to format (bump driver version)
 23  * March 1996, Rik Faith (faith@cs.unc.edu):
 24  *    Prohibit APM BIOS calls unless apm_enabled.
 25  *    (Thanks to Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>)
 26  * April 1996, Stephen Rothwell (sfr@canb.auug.org.au)
 27  *    Version 1.0 and 1.1
 28  * May 1996, Version 1.2
 29  * Feb 1998, Version 1.3
 30  * Feb 1998, Version 1.4
 31  * Aug 1998, Version 1.5
 32  * Sep 1998, Version 1.6
 33  * Nov 1998, Version 1.7
 34  * Jan 1999, Version 1.8
 35  * Jan 1999, Version 1.9
 36  * Oct 1999, Version 1.10
 37  * Nov 1999, Version 1.11
 38  * Jan 2000, Version 1.12
 39  * Feb 2000, Version 1.13
 40  * Nov 2000, Version 1.14
 41  * Oct 2001, Version 1.15
 42  * Jan 2002, Version 1.16
 43  * Oct 2002, Version 1.16ac
 44  *
 45  * History:
 46  *    0.6b: first version in official kernel, Linux 1.3.46
 47  *    0.7: changed /proc/apm format, Linux 1.3.58
 48  *    0.8: fixed gcc 2.7.[12] compilation problems, Linux 1.3.59
 49  *    0.9: only call bios if bios is present, Linux 1.3.72
 50  *    1.0: use fixed device number, consolidate /proc/apm into this file,
 51  *         Linux 1.3.85
 52  *    1.1: support user-space standby and suspend, power off after system
 53  *         halted, Linux 1.3.98
 54  *    1.2: When resetting RTC after resume, take care so that the time
 55  *         is only incorrect by 30-60mS (vs. 1S previously) (Gabor J. Toth
 56  *         <jtoth@princeton.edu>); improve interaction between
 57  *         screen-blanking and gpm (Stephen Rothwell); Linux 1.99.4
 58  *    1.2a:Simple change to stop mysterious bug reports with SMP also added
 59  *         levels to the printk calls. APM is not defined for SMP machines.
 60  *         The new replacement for it is, but Linux doesn't yet support this.
 61  *         Alan Cox Linux 2.1.55
 62  *    1.3: Set up a valid data descriptor 0x40 for buggy BIOS's
 63  *    1.4: Upgraded to support APM 1.2. Integrated ThinkPad suspend patch by
 64  *         Dean Gaudet <dgaudet@arctic.org>.
 65  *         C. Scott Ananian <cananian@alumni.princeton.edu> Linux 2.1.87
 66  *    1.5: Fix segment register reloading (in case of bad segments saved
 67  *         across BIOS call).
 68  *         Stephen Rothwell
 69  *    1.6: Cope with compiler/assembler differences.
 70  *         Only try to turn off the first display device.
 71  *         Fix OOPS at power off with no APM BIOS by Jan Echternach
 72  *                   <echter@informatik.uni-rostock.de>
 73  *         Stephen Rothwell
 74  *    1.7: Modify driver's cached copy of the disabled/disengaged flags
 75  *         to reflect current state of APM BIOS.
 76  *         Chris Rankin <rankinc@bellsouth.net>
 77  *         Reset interrupt 0 timer to 100Hz after suspend
 78  *         Chad Miller <cmiller@surfsouth.com>
 79  *         Add CONFIG_APM_IGNORE_SUSPEND_BOUNCE
 80  *         Richard Gooch <rgooch@atnf.csiro.au>
 81  *         Allow boot time disabling of APM
 82  *         Make boot messages far less verbose by default
 83  *         Make asm safer
 84  *         Stephen Rothwell
 85  *    1.8: Add CONFIG_APM_RTC_IS_GMT
 86  *         Richard Gooch <rgooch@atnf.csiro.au>
 87  *         change APM_NOINTS to CONFIG_APM_ALLOW_INTS
 88  *         remove dependency on CONFIG_PROC_FS
 89  *         Stephen Rothwell
 90  *    1.9: Fix small typo.  <laslo@wodip.opole.pl>
 91  *         Try to cope with BIOS's that need to have all display
 92  *         devices blanked and not just the first one.
 93  *         Ross Paterson <ross@soi.city.ac.uk>
 94  *         Fix segment limit setting it has always been wrong as
 95  *         the segments needed to have byte granularity.
 96  *         Mark a few things __init.
 97  *         Add hack to allow power off of SMP systems by popular request.
 98  *         Use CONFIG_SMP instead of __SMP__
 99  *         Ignore BOUNCES for three seconds.
100  *         Stephen Rothwell
101  *   1.10: Fix for Thinkpad return code.
102  *         Merge 2.2 and 2.3 drivers.
103  *         Remove APM dependencies in arch/i386/kernel/process.c
104  *         Remove APM dependencies in drivers/char/sysrq.c
105  *         Reset time across standby.
106  *         Allow more inititialisation on SMP.
107  *         Remove CONFIG_APM_POWER_OFF and make it boot time
108  *         configurable (default on).
109  *         Make debug only a boot time parameter (remove APM_DEBUG).
110  *         Try to blank all devices on any error.
111  *   1.11: Remove APM dependencies in drivers/char/console.c
112  *         Check nr_running to detect if we are idle (from
113  *         Borislav Deianov <borislav@lix.polytechnique.fr>)
114  *         Fix for bioses that don't zero the top part of the
115  *         entrypoint offset (Mario Sitta <sitta@al.unipmn.it>)
116  *         (reported by Panos Katsaloulis <teras@writeme.com>).
117  *         Real mode power off patch (Walter Hofmann
118  *         <Walter.Hofmann@physik.stud.uni-erlangen.de>).
119  *   1.12: Remove CONFIG_SMP as the compiler will optimize
120  *         the code away anyway (smp_num_cpus == 1 in UP)
121  *         noted by Artur Skawina <skawina@geocities.com>.
122  *         Make power off under SMP work again.
123  *         Fix thinko with initial engaging of BIOS.
124  *         Make sure power off only happens on CPU 0
125  *         (Paul "Rusty" Russell <rusty@rustcorp.com.au>).
126  *         Do error notification to user mode if BIOS calls fail.
127  *         Move entrypoint offset fix to ...boot/setup.S
128  *         where it belongs (Cosmos <gis88564@cis.nctu.edu.tw>).
129  *         Remove smp-power-off. SMP users must now specify
130  *         "apm=power-off" on the kernel command line. Suggested
131  *         by Jim Avera <jima@hal.com>, modified by Alan Cox
132  *         <alan@lxorguk.ukuu.org.uk>.
133  *         Register the /proc/apm entry even on SMP so that
134  *         scripts that check for it before doing power off
135  *         work (Jim Avera <jima@hal.com>).
136  *   1.13: Changes for new pm_ interfaces (Andy Henroid
137  *         <andy_henroid@yahoo.com>).
138  *         Modularize the code.
139  *         Fix the Thinkpad (again) :-( (CONFIG_APM_IGNORE_MULTIPLE_SUSPENDS
140  *         is now the way life works).
141  *         Fix thinko in suspend() (wrong return).
142  *         Notify drivers on critical suspend.
143  *         Make kapmd absorb more idle time (Pavel Machek <pavel@ucw.cz>
144  *         modified by sfr).
145  *         Disable interrupts while we are suspended (Andy Henroid
146  *         <andy_henroid@yahoo.com> fixed by sfr).
147  *         Make power off work on SMP again (Tony Hoyle
148  *         <tmh@magenta-logic.com> and <zlatko@iskon.hr>) modified by sfr.
149  *         Remove CONFIG_APM_SUSPEND_BOUNCE.  The bounce ignore
150  *         interval is now configurable.
151  *   1.14: Make connection version persist across module unload/load.
152  *         Enable and engage power management earlier.
153  *         Disengage power management on module unload.
154  *         Changed to use the sysrq-register hack for registering the
155  *         power off function called by magic sysrq based upon discussions
156  *         in irc://irc.openprojects.net/#kernelnewbies
157  *         (Crutcher Dunnavant <crutcher+kernel@datastacks.com>).
158  *         Make CONFIG_APM_REAL_MODE_POWER_OFF run time configurable.
159  *         (Arjan van de Ven <arjanv@redhat.com>) modified by sfr.
160  *         Work around byte swap bug in one of the Vaio's BIOS's
161  *         (Marc Boucher <marc@mbsi.ca>).
162  *         Exposed the disable flag to dmi so that we can handle known
163  *         broken APM (Alan Cox <alan@lxorguk.ukuu.org.uk>).
164  *   1.14ac: If the BIOS says "I slowed the CPU down" then don't spin
165  *         calling it - instead idle. (Alan Cox <alan@lxorguk.ukuu.org.uk>)
166  *         If an APM idle fails log it and idle sensibly
167  *   1.15: Don't queue events to clients who open the device O_WRONLY.
168  *         Don't expect replies from clients who open the device O_RDONLY.
169  *         (Idea from Thomas Hood)
170  *         Minor waitqueue cleanups. (John Fremlin <chief@bandits.org>)
171  *   1.16: Fix idle calling. (Andreas Steinmetz <ast@domdv.de> et al.)
172  *         Notify listeners of standby or suspend events before notifying
173  *         drivers. Return EBUSY to ioctl() if suspend is rejected.
174  *         (Russell King <rmk@arm.linux.org.uk> and Thomas Hood)
175  *         Ignore first resume after we generate our own resume event
176  *         after a suspend (Thomas Hood)
177  *         Daemonize now gets rid of our controlling terminal (sfr).
178  *         CONFIG_APM_CPU_IDLE now just affects the default value of
179  *         idle_threshold (sfr).
180  *         Change name of kernel apm daemon (as it no longer idles) (sfr).
181  *   1.16ac: Fix up SMP support somewhat. You can now force SMP on and we
182  *         make _all_ APM calls on the CPU#0. Fix unsafe sign bug.
183  *         TODO: determine if its "boot CPU" or "CPU0" we want to lock to.
184  *
185  * APM 1.1 Reference:
186  *
187  *   Intel Corporation, Microsoft Corporation. Advanced Power Management
188  *   (APM) BIOS Interface Specification, Revision 1.1, September 1993.
189  *   Intel Order Number 241704-001.  Microsoft Part Number 781-110-X01.
190  *
191  * [This document is available free from Intel by calling 800.628.8686 (fax
192  * 916.356.6100) or 800.548.4725; or from
193  * http://www.microsoft.com/whdc/archive/amp_12.mspx  It is also
194  * available from Microsoft by calling 206.882.8080.]
195  *
196  * APM 1.2 Reference:
197  *   Intel Corporation, Microsoft Corporation. Advanced Power Management
198  *   (APM) BIOS Interface Specification, Revision 1.2, February 1996.
199  *
200  * [This document is available from Microsoft at:
201  *    http://www.microsoft.com/whdc/archive/amp_12.mspx]
202  */
203 
204 #define pr_fmt(fmt) "apm: " fmt
205 
206 #include <linux/module.h>
207 
208 #include <linux/poll.h>
209 #include <linux/types.h>
210 #include <linux/stddef.h>
211 #include <linux/timer.h>
212 #include <linux/fcntl.h>
213 #include <linux/slab.h>
214 #include <linux/stat.h>
215 #include <linux/proc_fs.h>
216 #include <linux/seq_file.h>
217 #include <linux/miscdevice.h>
218 #include <linux/apm_bios.h>
219 #include <linux/init.h>
220 #include <linux/time.h>
221 #include <linux/sched.h>
222 #include <linux/pm.h>
223 #include <linux/capability.h>
224 #include <linux/device.h>
225 #include <linux/kernel.h>
226 #include <linux/freezer.h>
227 #include <linux/smp.h>
228 #include <linux/dmi.h>
229 #include <linux/suspend.h>
230 #include <linux/kthread.h>
231 #include <linux/jiffies.h>
232 #include <linux/acpi.h>
233 #include <linux/syscore_ops.h>
234 #include <linux/i8253.h>
235 #include <linux/cpuidle.h>
236 
237 #include <asm/uaccess.h>
238 #include <asm/desc.h>
239 #include <asm/olpc.h>
240 #include <asm/paravirt.h>
241 #include <asm/reboot.h>
242 
243 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
244 extern int (*console_blank_hook)(int);
245 #endif
246 
247 /*
248  * The apm_bios device is one of the misc char devices.
249  * This is its minor number.
250  */
251 #define APM_MINOR_DEV   134
252 
253 /*
254  * Various options can be changed at boot time as follows:
255  * (We allow underscores for compatibility with the modules code)
256  *      apm=on/off                      enable/disable APM
257  *          [no-]allow[-_]ints          allow interrupts during BIOS calls
258  *          [no-]broken[-_]psr          BIOS has a broken GetPowerStatus call
259  *          [no-]realmode[-_]power[-_]off       switch to real mode before
260  *                                              powering off
261  *          [no-]debug                  log some debugging messages
262  *          [no-]power[-_]off           power off on shutdown
263  *          [no-]smp                    Use apm even on an SMP box
264  *          bounce[-_]interval=<n>      number of ticks to ignore suspend
265  *                                      bounces
266  *          idle[-_]threshold=<n>       System idle percentage above which to
267  *                                      make APM BIOS idle calls. Set it to
268  *                                      100 to disable.
269  *          idle[-_]period=<n>          Period (in 1/100s of a second) over
270  *                                      which the idle percentage is
271  *                                      calculated.
272  */
273 
274 /* KNOWN PROBLEM MACHINES:
275  *
276  * U: TI 4000M TravelMate: BIOS is *NOT* APM compliant
277  *                         [Confirmed by TI representative]
278  * ?: ACER 486DX4/75: uses dseg 0040, in violation of APM specification
279  *                    [Confirmed by BIOS disassembly]
280  *                    [This may work now ...]
281  * P: Toshiba 1950S: battery life information only gets updated after resume
282  * P: Midwest Micro Soundbook Elite DX2/66 monochrome: screen blanking
283  *      broken in BIOS [Reported by Garst R. Reese <reese@isn.net>]
284  * ?: AcerNote-950: oops on reading /proc/apm - workaround is a WIP
285  *      Neale Banks <neale@lowendale.com.au> December 2000
286  *
287  * Legend: U = unusable with APM patches
288  *         P = partially usable with APM patches
289  */
290 
291 /*
292  * Define as 1 to make the driver always call the APM BIOS busy
293  * routine even if the clock was not reported as slowed by the
294  * idle routine.  Otherwise, define as 0.
295  */
296 #define ALWAYS_CALL_BUSY   1
297 
298 /*
299  * Define to make the APM BIOS calls zero all data segment registers (so
300  * that an incorrect BIOS implementation will cause a kernel panic if it
301  * tries to write to arbitrary memory).
302  */
303 #define APM_ZERO_SEGS
304 
305 #include <asm/apm.h>
306 
307 /*
308  * Define to re-initialize the interrupt 0 timer to 100 Hz after a suspend.
309  * This patched by Chad Miller <cmiller@surfsouth.com>, original code by
310  * David Chen <chen@ctpa04.mit.edu>
311  */
312 #undef INIT_TIMER_AFTER_SUSPEND
313 
314 #ifdef INIT_TIMER_AFTER_SUSPEND
315 #include <linux/timex.h>
316 #include <asm/io.h>
317 #include <linux/delay.h>
318 #endif
319 
320 /*
321  * Need to poll the APM BIOS every second
322  */
323 #define APM_CHECK_TIMEOUT       (HZ)
324 
325 /*
326  * Ignore suspend events for this amount of time after a resume
327  */
328 #define DEFAULT_BOUNCE_INTERVAL (3 * HZ)
329 
330 /*
331  * Maximum number of events stored
332  */
333 #define APM_MAX_EVENTS          20
334 
335 /*
336  * The per-file APM data
337  */
338 struct apm_user {
339         int             magic;
340         struct apm_user *next;
341         unsigned int    suser: 1;
342         unsigned int    writer: 1;
343         unsigned int    reader: 1;
344         unsigned int    suspend_wait: 1;
345         int             suspend_result;
346         int             suspends_pending;
347         int             standbys_pending;
348         int             suspends_read;
349         int             standbys_read;
350         int             event_head;
351         int             event_tail;
352         apm_event_t     events[APM_MAX_EVENTS];
353 };
354 
355 /*
356  * The magic number in apm_user
357  */
358 #define APM_BIOS_MAGIC          0x4101
359 
360 /*
361  * idle percentage above which bios idle calls are done
362  */
363 #ifdef CONFIG_APM_CPU_IDLE
364 #define DEFAULT_IDLE_THRESHOLD  95
365 #else
366 #define DEFAULT_IDLE_THRESHOLD  100
367 #endif
368 #define DEFAULT_IDLE_PERIOD     (100 / 3)
369 
370 static int apm_cpu_idle(struct cpuidle_device *dev,
371                         struct cpuidle_driver *drv, int index);
372 
373 static struct cpuidle_driver apm_idle_driver = {
374         .name = "apm_idle",
375         .owner = THIS_MODULE,
376         .states = {
377                 { /* entry 0 is for polling */ },
378                 { /* entry 1 is for APM idle */
379                         .name = "APM",
380                         .desc = "APM idle",
381                         .flags = CPUIDLE_FLAG_TIME_VALID,
382                         .exit_latency = 250,    /* WAG */
383                         .target_residency = 500,        /* WAG */
384                         .enter = &apm_cpu_idle
385                 },
386         },
387         .state_count = 2,
388 };
389 
390 static struct cpuidle_device apm_cpuidle_device;
391 
392 /*
393  * Local variables
394  */
395 static struct {
396         unsigned long   offset;
397         unsigned short  segment;
398 } apm_bios_entry;
399 static int clock_slowed;
400 static int idle_threshold __read_mostly = DEFAULT_IDLE_THRESHOLD;
401 static int idle_period __read_mostly = DEFAULT_IDLE_PERIOD;
402 static int suspends_pending;
403 static int standbys_pending;
404 static int ignore_sys_suspend;
405 static int ignore_normal_resume;
406 static int bounce_interval __read_mostly = DEFAULT_BOUNCE_INTERVAL;
407 
408 static bool debug __read_mostly;
409 static bool smp __read_mostly;
410 static int apm_disabled = -1;
411 #ifdef CONFIG_SMP
412 static bool power_off;
413 #else
414 static bool power_off = 1;
415 #endif
416 static bool realmode_power_off;
417 #ifdef CONFIG_APM_ALLOW_INTS
418 static bool allow_ints = 1;
419 #else
420 static bool allow_ints;
421 #endif
422 static bool broken_psr;
423 
424 static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
425 static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
426 static struct apm_user *user_list;
427 static DEFINE_SPINLOCK(user_list_lock);
428 static DEFINE_MUTEX(apm_mutex);
429 
430 /*
431  * Set up a segment that references the real mode segment 0x40
432  * that extends up to the end of page zero (that we have reserved).
433  * This is for buggy BIOS's that refer to (real mode) segment 0x40
434  * even though they are called in protected mode.
435  */
436 static struct desc_struct bad_bios_desc = GDT_ENTRY_INIT(0x4092,
437                         (unsigned long)__va(0x400UL), PAGE_SIZE - 0x400 - 1);
438 
439 static const char driver_version[] = "1.16ac";  /* no spaces */
440 
441 static struct task_struct *kapmd_task;
442 
443 /*
444  *      APM event names taken from the APM 1.2 specification. These are
445  *      the message codes that the BIOS uses to tell us about events
446  */
447 static const char * const apm_event_name[] = {
448         "system standby",
449         "system suspend",
450         "normal resume",
451         "critical resume",
452         "low battery",
453         "power status change",
454         "update time",
455         "critical suspend",
456         "user standby",
457         "user suspend",
458         "system standby resume",
459         "capabilities change"
460 };
461 #define NR_APM_EVENT_NAME ARRAY_SIZE(apm_event_name)
462 
463 typedef struct lookup_t {
464         int     key;
465         char    *msg;
466 } lookup_t;
467 
468 /*
469  *      The BIOS returns a set of standard error codes in AX when the
470  *      carry flag is set.
471  */
472 
473 static const lookup_t error_table[] = {
474 /* N/A  { APM_SUCCESS,          "Operation succeeded" }, */
475         { APM_DISABLED,         "Power management disabled" },
476         { APM_CONNECTED,        "Real mode interface already connected" },
477         { APM_NOT_CONNECTED,    "Interface not connected" },
478         { APM_16_CONNECTED,     "16 bit interface already connected" },
479 /* N/A  { APM_16_UNSUPPORTED,   "16 bit interface not supported" }, */
480         { APM_32_CONNECTED,     "32 bit interface already connected" },
481         { APM_32_UNSUPPORTED,   "32 bit interface not supported" },
482         { APM_BAD_DEVICE,       "Unrecognized device ID" },
483         { APM_BAD_PARAM,        "Parameter out of range" },
484         { APM_NOT_ENGAGED,      "Interface not engaged" },
485         { APM_BAD_FUNCTION,     "Function not supported" },
486         { APM_RESUME_DISABLED,  "Resume timer disabled" },
487         { APM_BAD_STATE,        "Unable to enter requested state" },
488 /* N/A  { APM_NO_EVENTS,        "No events pending" }, */
489         { APM_NO_ERROR,         "BIOS did not set a return code" },
490         { APM_NOT_PRESENT,      "No APM present" }
491 };
492 #define ERROR_COUNT     ARRAY_SIZE(error_table)
493 
494 /**
495  *      apm_error       -       display an APM error
496  *      @str: information string
497  *      @err: APM BIOS return code
498  *
499  *      Write a meaningful log entry to the kernel log in the event of
500  *      an APM error.  Note that this also handles (negative) kernel errors.
501  */
502 
503 static void apm_error(char *str, int err)
504 {
505         int i;
506 
507         for (i = 0; i < ERROR_COUNT; i++)
508                 if (error_table[i].key == err)
509                         break;
510         if (i < ERROR_COUNT)
511                 pr_notice("%s: %s\n", str, error_table[i].msg);
512         else if (err < 0)
513                 pr_notice("%s: linux error code %i\n", str, err);
514         else
515                 pr_notice("%s: unknown error code %#2.2x\n",
516                        str, err);
517 }
518 
519 /*
520  * These are the actual BIOS calls.  Depending on APM_ZERO_SEGS and
521  * apm_info.allow_ints, we are being really paranoid here!  Not only
522  * are interrupts disabled, but all the segment registers (except SS)
523  * are saved and zeroed this means that if the BIOS tries to reference
524  * any data without explicitly loading the segment registers, the kernel
525  * will fault immediately rather than have some unforeseen circumstances
526  * for the rest of the kernel.  And it will be very obvious!  :-) Doing
527  * this depends on CS referring to the same physical memory as DS so that
528  * DS can be zeroed before the call. Unfortunately, we can't do anything
529  * about the stack segment/pointer.  Also, we tell the compiler that
530  * everything could change.
531  *
532  * Also, we KNOW that for the non error case of apm_bios_call, there
533  * is no useful data returned in the low order 8 bits of eax.
534  */
535 
536 static inline unsigned long __apm_irq_save(void)
537 {
538         unsigned long flags;
539         local_save_flags(flags);
540         if (apm_info.allow_ints) {
541                 if (irqs_disabled_flags(flags))
542                         local_irq_enable();
543         } else
544                 local_irq_disable();
545 
546         return flags;
547 }
548 
549 #define apm_irq_save(flags) \
550         do { flags = __apm_irq_save(); } while (0)
551 
552 static inline void apm_irq_restore(unsigned long flags)
553 {
554         if (irqs_disabled_flags(flags))
555                 local_irq_disable();
556         else if (irqs_disabled())
557                 local_irq_enable();
558 }
559 
560 #ifdef APM_ZERO_SEGS
561 #       define APM_DECL_SEGS \
562                 unsigned int saved_fs; unsigned int saved_gs;
563 #       define APM_DO_SAVE_SEGS \
564                 savesegment(fs, saved_fs); savesegment(gs, saved_gs)
565 #       define APM_DO_RESTORE_SEGS \
566                 loadsegment(fs, saved_fs); loadsegment(gs, saved_gs)
567 #else
568 #       define APM_DECL_SEGS
569 #       define APM_DO_SAVE_SEGS
570 #       define APM_DO_RESTORE_SEGS
571 #endif
572 
573 struct apm_bios_call {
574         u32 func;
575         /* In and out */
576         u32 ebx;
577         u32 ecx;
578         /* Out only */
579         u32 eax;
580         u32 edx;
581         u32 esi;
582 
583         /* Error: -ENOMEM, or bits 8-15 of eax */
584         int err;
585 };
586 
587 /**
588  *      __apm_bios_call - Make an APM BIOS 32bit call
589  *      @_call: pointer to struct apm_bios_call.
590  *
591  *      Make an APM call using the 32bit protected mode interface. The
592  *      caller is responsible for knowing if APM BIOS is configured and
593  *      enabled. This call can disable interrupts for a long period of
594  *      time on some laptops.  The return value is in AH and the carry
595  *      flag is loaded into AL.  If there is an error, then the error
596  *      code is returned in AH (bits 8-15 of eax) and this function
597  *      returns non-zero.
598  *
599  *      Note: this makes the call on the current CPU.
600  */
601 static long __apm_bios_call(void *_call)
602 {
603         APM_DECL_SEGS
604         unsigned long           flags;
605         int                     cpu;
606         struct desc_struct      save_desc_40;
607         struct desc_struct      *gdt;
608         struct apm_bios_call    *call = _call;
609 
610         cpu = get_cpu();
611         BUG_ON(cpu != 0);
612         gdt = get_cpu_gdt_table(cpu);
613         save_desc_40 = gdt[0x40 / 8];
614         gdt[0x40 / 8] = bad_bios_desc;
615 
616         apm_irq_save(flags);
617         APM_DO_SAVE_SEGS;
618         apm_bios_call_asm(call->func, call->ebx, call->ecx,
619                           &call->eax, &call->ebx, &call->ecx, &call->edx,
620                           &call->esi);
621         APM_DO_RESTORE_SEGS;
622         apm_irq_restore(flags);
623         gdt[0x40 / 8] = save_desc_40;
624         put_cpu();
625 
626         return call->eax & 0xff;
627 }
628 
629 /* Run __apm_bios_call or __apm_bios_call_simple on CPU 0 */
630 static int on_cpu0(long (*fn)(void *), struct apm_bios_call *call)
631 {
632         int ret;
633 
634         /* Don't bother with work_on_cpu in the common case, so we don't
635          * have to worry about OOM or overhead. */
636         if (get_cpu() == 0) {
637                 ret = fn(call);
638                 put_cpu();
639         } else {
640                 put_cpu();
641                 ret = work_on_cpu(0, fn, call);
642         }
643 
644         /* work_on_cpu can fail with -ENOMEM */
645         if (ret < 0)
646                 call->err = ret;
647         else
648                 call->err = (call->eax >> 8) & 0xff;
649 
650         return ret;
651 }
652 
653 /**
654  *      apm_bios_call   -       Make an APM BIOS 32bit call (on CPU 0)
655  *      @call: the apm_bios_call registers.
656  *
657  *      If there is an error, it is returned in @call.err.
658  */
659 static int apm_bios_call(struct apm_bios_call *call)
660 {
661         return on_cpu0(__apm_bios_call, call);
662 }
663 
664 /**
665  *      __apm_bios_call_simple - Make an APM BIOS 32bit call (on CPU 0)
666  *      @_call: pointer to struct apm_bios_call.
667  *
668  *      Make a BIOS call that returns one value only, or just status.
669  *      If there is an error, then the error code is returned in AH
670  *      (bits 8-15 of eax) and this function returns non-zero (it can
671  *      also return -ENOMEM). This is used for simpler BIOS operations.
672  *      This call may hold interrupts off for a long time on some laptops.
673  *
674  *      Note: this makes the call on the current CPU.
675  */
676 static long __apm_bios_call_simple(void *_call)
677 {
678         u8                      error;
679         APM_DECL_SEGS
680         unsigned long           flags;
681         int                     cpu;
682         struct desc_struct      save_desc_40;
683         struct desc_struct      *gdt;
684         struct apm_bios_call    *call = _call;
685 
686         cpu = get_cpu();
687         BUG_ON(cpu != 0);
688         gdt = get_cpu_gdt_table(cpu);
689         save_desc_40 = gdt[0x40 / 8];
690         gdt[0x40 / 8] = bad_bios_desc;
691 
692         apm_irq_save(flags);
693         APM_DO_SAVE_SEGS;
694         error = apm_bios_call_simple_asm(call->func, call->ebx, call->ecx,
695                                          &call->eax);
696         APM_DO_RESTORE_SEGS;
697         apm_irq_restore(flags);
698         gdt[0x40 / 8] = save_desc_40;
699         put_cpu();
700         return error;
701 }
702 
703 /**
704  *      apm_bios_call_simple    -       make a simple APM BIOS 32bit call
705  *      @func: APM function to invoke
706  *      @ebx_in: EBX register value for BIOS call
707  *      @ecx_in: ECX register value for BIOS call
708  *      @eax: EAX register on return from the BIOS call
709  *      @err: bits
710  *
711  *      Make a BIOS call that returns one value only, or just status.
712  *      If there is an error, then the error code is returned in @err
713  *      and this function returns non-zero. This is used for simpler
714  *      BIOS operations.  This call may hold interrupts off for a long
715  *      time on some laptops.
716  */
717 static int apm_bios_call_simple(u32 func, u32 ebx_in, u32 ecx_in, u32 *eax,
718                                 int *err)
719 {
720         struct apm_bios_call call;
721         int ret;
722 
723         call.func = func;
724         call.ebx = ebx_in;
725         call.ecx = ecx_in;
726 
727         ret = on_cpu0(__apm_bios_call_simple, &call);
728         *eax = call.eax;
729         *err = call.err;
730         return ret;
731 }
732 
733 /**
734  *      apm_driver_version      -       APM driver version
735  *      @val:   loaded with the APM version on return
736  *
737  *      Retrieve the APM version supported by the BIOS. This is only
738  *      supported for APM 1.1 or higher. An error indicates APM 1.0 is
739  *      probably present.
740  *
741  *      On entry val should point to a value indicating the APM driver
742  *      version with the high byte being the major and the low byte the
743  *      minor number both in BCD
744  *
745  *      On return it will hold the BIOS revision supported in the
746  *      same format.
747  */
748 
749 static int apm_driver_version(u_short *val)
750 {
751         u32 eax;
752         int err;
753 
754         if (apm_bios_call_simple(APM_FUNC_VERSION, 0, *val, &eax, &err))
755                 return err;
756         *val = eax;
757         return APM_SUCCESS;
758 }
759 
760 /**
761  *      apm_get_event   -       get an APM event from the BIOS
762  *      @event: pointer to the event
763  *      @info: point to the event information
764  *
765  *      The APM BIOS provides a polled information for event
766  *      reporting. The BIOS expects to be polled at least every second
767  *      when events are pending. When a message is found the caller should
768  *      poll until no more messages are present.  However, this causes
769  *      problems on some laptops where a suspend event notification is
770  *      not cleared until it is acknowledged.
771  *
772  *      Additional information is returned in the info pointer, providing
773  *      that APM 1.2 is in use. If no messges are pending the value 0x80
774  *      is returned (No power management events pending).
775  */
776 static int apm_get_event(apm_event_t *event, apm_eventinfo_t *info)
777 {
778         struct apm_bios_call call;
779 
780         call.func = APM_FUNC_GET_EVENT;
781         call.ebx = call.ecx = 0;
782 
783         if (apm_bios_call(&call))
784                 return call.err;
785 
786         *event = call.ebx;
787         if (apm_info.connection_version < 0x0102)
788                 *info = ~0; /* indicate info not valid */
789         else
790                 *info = call.ecx;
791         return APM_SUCCESS;
792 }
793 
794 /**
795  *      set_power_state -       set the power management state
796  *      @what: which items to transition
797  *      @state: state to transition to
798  *
799  *      Request an APM change of state for one or more system devices. The
800  *      processor state must be transitioned last of all. what holds the
801  *      class of device in the upper byte and the device number (0xFF for
802  *      all) for the object to be transitioned.
803  *
804  *      The state holds the state to transition to, which may in fact
805  *      be an acceptance of a BIOS requested state change.
806  */
807 
808 static int set_power_state(u_short what, u_short state)
809 {
810         u32 eax;
811         int err;
812 
813         if (apm_bios_call_simple(APM_FUNC_SET_STATE, what, state, &eax, &err))
814                 return err;
815         return APM_SUCCESS;
816 }
817 
818 /**
819  *      set_system_power_state - set system wide power state
820  *      @state: which state to enter
821  *
822  *      Transition the entire system into a new APM power state.
823  */
824 
825 static int set_system_power_state(u_short state)
826 {
827         return set_power_state(APM_DEVICE_ALL, state);
828 }
829 
830 /**
831  *      apm_do_idle     -       perform power saving
832  *
833  *      This function notifies the BIOS that the processor is (in the view
834  *      of the OS) idle. It returns -1 in the event that the BIOS refuses
835  *      to handle the idle request. On a success the function returns 1
836  *      if the BIOS did clock slowing or 0 otherwise.
837  */
838 
839 static int apm_do_idle(void)
840 {
841         u32 eax;
842         u8 ret = 0;
843         int idled = 0;
844         int polling;
845         int err = 0;
846 
847         polling = !!(current_thread_info()->status & TS_POLLING);
848         if (polling) {
849                 current_thread_info()->status &= ~TS_POLLING;
850                 /*
851                  * TS_POLLING-cleared state must be visible before we
852                  * test NEED_RESCHED:
853                  */
854                 smp_mb();
855         }
856         if (!need_resched()) {
857                 idled = 1;
858                 ret = apm_bios_call_simple(APM_FUNC_IDLE, 0, 0, &eax, &err);
859         }
860         if (polling)
861                 current_thread_info()->status |= TS_POLLING;
862 
863         if (!idled)
864                 return 0;
865 
866         if (ret) {
867                 static unsigned long t;
868 
869                 /* This always fails on some SMP boards running UP kernels.
870                  * Only report the failure the first 5 times.
871                  */
872                 if (++t < 5) {
873                         printk(KERN_DEBUG "apm_do_idle failed (%d)\n", err);
874                         t = jiffies;
875                 }
876                 return -1;
877         }
878         clock_slowed = (apm_info.bios.flags & APM_IDLE_SLOWS_CLOCK) != 0;
879         return clock_slowed;
880 }
881 
882 /**
883  *      apm_do_busy     -       inform the BIOS the CPU is busy
884  *
885  *      Request that the BIOS brings the CPU back to full performance.
886  */
887 
888 static void apm_do_busy(void)
889 {
890         u32 dummy;
891         int err;
892 
893         if (clock_slowed || ALWAYS_CALL_BUSY) {
894                 (void)apm_bios_call_simple(APM_FUNC_BUSY, 0, 0, &dummy, &err);
895                 clock_slowed = 0;
896         }
897 }
898 
899 /*
900  * If no process has really been interested in
901  * the CPU for some time, we want to call BIOS
902  * power management - we probably want
903  * to conserve power.
904  */
905 #define IDLE_CALC_LIMIT (HZ * 100)
906 #define IDLE_LEAKY_MAX  16
907 
908 /**
909  * apm_cpu_idle         -       cpu idling for APM capable Linux
910  *
911  * This is the idling function the kernel executes when APM is available. It
912  * tries to do BIOS powermanagement based on the average system idle time.
913  * Furthermore it calls the system default idle routine.
914  */
915 
916 static int apm_cpu_idle(struct cpuidle_device *dev,
917         struct cpuidle_driver *drv, int index)
918 {
919         static int use_apm_idle; /* = 0 */
920         static unsigned int last_jiffies; /* = 0 */
921         static unsigned int last_stime; /* = 0 */
922         cputime_t stime;
923 
924         int apm_idle_done = 0;
925         unsigned int jiffies_since_last_check = jiffies - last_jiffies;
926         unsigned int bucket;
927 
928 recalc:
929         task_cputime(current, NULL, &stime);
930         if (jiffies_since_last_check > IDLE_CALC_LIMIT) {
931                 use_apm_idle = 0;
932         } else if (jiffies_since_last_check > idle_period) {
933                 unsigned int idle_percentage;
934 
935                 idle_percentage = stime - last_stime;
936                 idle_percentage *= 100;
937                 idle_percentage /= jiffies_since_last_check;
938                 use_apm_idle = (idle_percentage > idle_threshold);
939                 if (apm_info.forbid_idle)
940                         use_apm_idle = 0;
941         }
942 
943         last_jiffies = jiffies;
944         last_stime = stime;
945 
946         bucket = IDLE_LEAKY_MAX;
947 
948         while (!need_resched()) {
949                 if (use_apm_idle) {
950                         unsigned int t;
951 
952                         t = jiffies;
953                         switch (apm_do_idle()) {
954                         case 0:
955                                 apm_idle_done = 1;
956                                 if (t != jiffies) {
957                                         if (bucket) {
958                                                 bucket = IDLE_LEAKY_MAX;
959                                                 continue;
960                                         }
961                                 } else if (bucket) {
962                                         bucket--;
963                                         continue;
964                                 }
965                                 break;
966                         case 1:
967                                 apm_idle_done = 1;
968                                 break;
969                         default: /* BIOS refused */
970                                 break;
971                         }
972                 }
973                 default_idle();
974                 local_irq_disable();
975                 jiffies_since_last_check = jiffies - last_jiffies;
976                 if (jiffies_since_last_check > idle_period)
977                         goto recalc;
978         }
979 
980         if (apm_idle_done)
981                 apm_do_busy();
982 
983         return index;
984 }
985 
986 /**
987  *      apm_power_off   -       ask the BIOS to power off
988  *
989  *      Handle the power off sequence. This is the one piece of code we
990  *      will execute even on SMP machines. In order to deal with BIOS
991  *      bugs we support real mode APM BIOS power off calls. We also make
992  *      the SMP call on CPU0 as some systems will only honour this call
993  *      on their first cpu.
994  */
995 
996 static void apm_power_off(void)
997 {
998         /* Some bioses don't like being called from CPU != 0 */
999         if (apm_info.realmode_power_off) {
1000                 set_cpus_allowed_ptr(current, cpumask_of(0));
1001                 machine_real_restart(MRR_APM);
1002         } else {
1003                 (void)set_system_power_state(APM_STATE_OFF);
1004         }
1005 }
1006 
1007 #ifdef CONFIG_APM_DO_ENABLE
1008 
1009 /**
1010  *      apm_enable_power_management - enable BIOS APM power management
1011  *      @enable: enable yes/no
1012  *
1013  *      Enable or disable the APM BIOS power services.
1014  */
1015 
1016 static int apm_enable_power_management(int enable)
1017 {
1018         u32 eax;
1019         int err;
1020 
1021         if ((enable == 0) && (apm_info.bios.flags & APM_BIOS_DISENGAGED))
1022                 return APM_NOT_ENGAGED;
1023         if (apm_bios_call_simple(APM_FUNC_ENABLE_PM, APM_DEVICE_BALL,
1024                                  enable, &eax, &err))
1025                 return err;
1026         if (enable)
1027                 apm_info.bios.flags &= ~APM_BIOS_DISABLED;
1028         else
1029                 apm_info.bios.flags |= APM_BIOS_DISABLED;
1030         return APM_SUCCESS;
1031 }
1032 #endif
1033 
1034 /**
1035  *      apm_get_power_status    -       get current power state
1036  *      @status: returned status
1037  *      @bat: battery info
1038  *      @life: estimated life
1039  *
1040  *      Obtain the current power status from the APM BIOS. We return a
1041  *      status which gives the rough battery status, and current power
1042  *      source. The bat value returned give an estimate as a percentage
1043  *      of life and a status value for the battery. The estimated life
1044  *      if reported is a lifetime in secodnds/minutes at current powwer
1045  *      consumption.
1046  */
1047 
1048 static int apm_get_power_status(u_short *status, u_short *bat, u_short *life)
1049 {
1050         struct apm_bios_call call;
1051 
1052         call.func = APM_FUNC_GET_STATUS;
1053         call.ebx = APM_DEVICE_ALL;
1054         call.ecx = 0;
1055 
1056         if (apm_info.get_power_status_broken)
1057                 return APM_32_UNSUPPORTED;
1058         if (apm_bios_call(&call))
1059                 return call.err;
1060         *status = call.ebx;
1061         *bat = call.ecx;
1062         if (apm_info.get_power_status_swabinminutes) {
1063                 *life = swab16((u16)call.edx);
1064                 *life |= 0x8000;
1065         } else
1066                 *life = call.edx;
1067         return APM_SUCCESS;
1068 }
1069 
1070 #if 0
1071 static int apm_get_battery_status(u_short which, u_short *status,
1072                                   u_short *bat, u_short *life, u_short *nbat)
1073 {
1074         u32 eax;
1075         u32 ebx;
1076         u32 ecx;
1077         u32 edx;
1078         u32 esi;
1079 
1080         if (apm_info.connection_version < 0x0102) {
1081                 /* pretend we only have one battery. */
1082                 if (which != 1)
1083                         return APM_BAD_DEVICE;
1084                 *nbat = 1;
1085                 return apm_get_power_status(status, bat, life);
1086         }
1087 
1088         if (apm_bios_call(APM_FUNC_GET_STATUS, (0x8000 | (which)), 0, &eax,
1089                           &ebx, &ecx, &edx, &esi))
1090                 return (eax >> 8) & 0xff;
1091         *status = ebx;
1092         *bat = ecx;
1093         *life = edx;
1094         *nbat = esi;
1095         return APM_SUCCESS;
1096 }
1097 #endif
1098 
1099 /**
1100  *      apm_engage_power_management     -       enable PM on a device
1101  *      @device: identity of device
1102  *      @enable: on/off
1103  *
1104  *      Activate or deactive power management on either a specific device
1105  *      or the entire system (%APM_DEVICE_ALL).
1106  */
1107 
1108 static int apm_engage_power_management(u_short device, int enable)
1109 {
1110         u32 eax;
1111         int err;
1112 
1113         if ((enable == 0) && (device == APM_DEVICE_ALL)
1114             && (apm_info.bios.flags & APM_BIOS_DISABLED))
1115                 return APM_DISABLED;
1116         if (apm_bios_call_simple(APM_FUNC_ENGAGE_PM, device, enable,
1117                                  &eax, &err))
1118                 return err;
1119         if (device == APM_DEVICE_ALL) {
1120                 if (enable)
1121                         apm_info.bios.flags &= ~APM_BIOS_DISENGAGED;
1122                 else
1123                         apm_info.bios.flags |= APM_BIOS_DISENGAGED;
1124         }
1125         return APM_SUCCESS;
1126 }
1127 
1128 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1129 
1130 /**
1131  *      apm_console_blank       -       blank the display
1132  *      @blank: on/off
1133  *
1134  *      Attempt to blank the console, firstly by blanking just video device
1135  *      zero, and if that fails (some BIOSes don't support it) then it blanks
1136  *      all video devices. Typically the BIOS will do laptop backlight and
1137  *      monitor powerdown for us.
1138  */
1139 
1140 static int apm_console_blank(int blank)
1141 {
1142         int error = APM_NOT_ENGAGED; /* silence gcc */
1143         int i;
1144         u_short state;
1145         static const u_short dev[3] = { 0x100, 0x1FF, 0x101 };
1146 
1147         state = blank ? APM_STATE_STANDBY : APM_STATE_READY;
1148 
1149         for (i = 0; i < ARRAY_SIZE(dev); i++) {
1150                 error = set_power_state(dev[i], state);
1151 
1152                 if ((error == APM_SUCCESS) || (error == APM_NO_ERROR))
1153                         return 1;
1154 
1155                 if (error == APM_NOT_ENGAGED)
1156                         break;
1157         }
1158 
1159         if (error == APM_NOT_ENGAGED) {
1160                 static int tried;
1161                 int eng_error;
1162                 if (tried++ == 0) {
1163                         eng_error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1164                         if (eng_error) {
1165                                 apm_error("set display", error);
1166                                 apm_error("engage interface", eng_error);
1167                                 return 0;
1168                         } else
1169                                 return apm_console_blank(blank);
1170                 }
1171         }
1172         apm_error("set display", error);
1173         return 0;
1174 }
1175 #endif
1176 
1177 static int queue_empty(struct apm_user *as)
1178 {
1179         return as->event_head == as->event_tail;
1180 }
1181 
1182 static apm_event_t get_queued_event(struct apm_user *as)
1183 {
1184         if (++as->event_tail >= APM_MAX_EVENTS)
1185                 as->event_tail = 0;
1186         return as->events[as->event_tail];
1187 }
1188 
1189 static void queue_event(apm_event_t event, struct apm_user *sender)
1190 {
1191         struct apm_user *as;
1192 
1193         spin_lock(&user_list_lock);
1194         if (user_list == NULL)
1195                 goto out;
1196         for (as = user_list; as != NULL; as = as->next) {
1197                 if ((as == sender) || (!as->reader))
1198                         continue;
1199                 if (++as->event_head >= APM_MAX_EVENTS)
1200                         as->event_head = 0;
1201 
1202                 if (as->event_head == as->event_tail) {
1203                         static int notified;
1204 
1205                         if (notified++ == 0)
1206                                 pr_err("an event queue overflowed\n");
1207                         if (++as->event_tail >= APM_MAX_EVENTS)
1208                                 as->event_tail = 0;
1209                 }
1210                 as->events[as->event_head] = event;
1211                 if (!as->suser || !as->writer)
1212                         continue;
1213                 switch (event) {
1214                 case APM_SYS_SUSPEND:
1215                 case APM_USER_SUSPEND:
1216                         as->suspends_pending++;
1217                         suspends_pending++;
1218                         break;
1219 
1220                 case APM_SYS_STANDBY:
1221                 case APM_USER_STANDBY:
1222                         as->standbys_pending++;
1223                         standbys_pending++;
1224                         break;
1225                 }
1226         }
1227         wake_up_interruptible(&apm_waitqueue);
1228 out:
1229         spin_unlock(&user_list_lock);
1230 }
1231 
1232 static void reinit_timer(void)
1233 {
1234 #ifdef INIT_TIMER_AFTER_SUSPEND
1235         unsigned long flags;
1236 
1237         raw_spin_lock_irqsave(&i8253_lock, flags);
1238         /* set the clock to HZ */
1239         outb_p(0x34, PIT_MODE);         /* binary, mode 2, LSB/MSB, ch 0 */
1240         udelay(10);
1241         outb_p(LATCH & 0xff, PIT_CH0);  /* LSB */
1242         udelay(10);
1243         outb_p(LATCH >> 8, PIT_CH0);    /* MSB */
1244         udelay(10);
1245         raw_spin_unlock_irqrestore(&i8253_lock, flags);
1246 #endif
1247 }
1248 
1249 static int suspend(int vetoable)
1250 {
1251         int err;
1252         struct apm_user *as;
1253 
1254         dpm_suspend_start(PMSG_SUSPEND);
1255         dpm_suspend_end(PMSG_SUSPEND);
1256 
1257         local_irq_disable();
1258         syscore_suspend();
1259 
1260         local_irq_enable();
1261 
1262         save_processor_state();
1263         err = set_system_power_state(APM_STATE_SUSPEND);
1264         ignore_normal_resume = 1;
1265         restore_processor_state();
1266 
1267         local_irq_disable();
1268         reinit_timer();
1269 
1270         if (err == APM_NO_ERROR)
1271                 err = APM_SUCCESS;
1272         if (err != APM_SUCCESS)
1273                 apm_error("suspend", err);
1274         err = (err == APM_SUCCESS) ? 0 : -EIO;
1275 
1276         syscore_resume();
1277         local_irq_enable();
1278 
1279         dpm_resume_start(PMSG_RESUME);
1280         dpm_resume_end(PMSG_RESUME);
1281 
1282         queue_event(APM_NORMAL_RESUME, NULL);
1283         spin_lock(&user_list_lock);
1284         for (as = user_list; as != NULL; as = as->next) {
1285                 as->suspend_wait = 0;
1286                 as->suspend_result = err;
1287         }
1288         spin_unlock(&user_list_lock);
1289         wake_up_interruptible(&apm_suspend_waitqueue);
1290         return err;
1291 }
1292 
1293 static void standby(void)
1294 {
1295         int err;
1296 
1297         dpm_suspend_end(PMSG_SUSPEND);
1298 
1299         local_irq_disable();
1300         syscore_suspend();
1301         local_irq_enable();
1302 
1303         err = set_system_power_state(APM_STATE_STANDBY);
1304         if ((err != APM_SUCCESS) && (err != APM_NO_ERROR))
1305                 apm_error("standby", err);
1306 
1307         local_irq_disable();
1308         syscore_resume();
1309         local_irq_enable();
1310 
1311         dpm_resume_start(PMSG_RESUME);
1312 }
1313 
1314 static apm_event_t get_event(void)
1315 {
1316         int error;
1317         apm_event_t event = APM_NO_EVENTS; /* silence gcc */
1318         apm_eventinfo_t info;
1319 
1320         static int notified;
1321 
1322         /* we don't use the eventinfo */
1323         error = apm_get_event(&event, &info);
1324         if (error == APM_SUCCESS)
1325                 return event;
1326 
1327         if ((error != APM_NO_EVENTS) && (notified++ == 0))
1328                 apm_error("get_event", error);
1329 
1330         return 0;
1331 }
1332 
1333 static void check_events(void)
1334 {
1335         apm_event_t event;
1336         static unsigned long last_resume;
1337         static int ignore_bounce;
1338 
1339         while ((event = get_event()) != 0) {
1340                 if (debug) {
1341                         if (event <= NR_APM_EVENT_NAME)
1342                                 printk(KERN_DEBUG "apm: received %s notify\n",
1343                                        apm_event_name[event - 1]);
1344                         else
1345                                 printk(KERN_DEBUG "apm: received unknown "
1346                                        "event 0x%02x\n", event);
1347                 }
1348                 if (ignore_bounce
1349                     && (time_after(jiffies, last_resume + bounce_interval)))
1350                         ignore_bounce = 0;
1351 
1352                 switch (event) {
1353                 case APM_SYS_STANDBY:
1354                 case APM_USER_STANDBY:
1355                         queue_event(event, NULL);
1356                         if (standbys_pending <= 0)
1357                                 standby();
1358                         break;
1359 
1360                 case APM_USER_SUSPEND:
1361 #ifdef CONFIG_APM_IGNORE_USER_SUSPEND
1362                         if (apm_info.connection_version > 0x100)
1363                                 set_system_power_state(APM_STATE_REJECT);
1364                         break;
1365 #endif
1366                 case APM_SYS_SUSPEND:
1367                         if (ignore_bounce) {
1368                                 if (apm_info.connection_version > 0x100)
1369                                         set_system_power_state(APM_STATE_REJECT);
1370                                 break;
1371                         }
1372                         /*
1373                          * If we are already processing a SUSPEND,
1374                          * then further SUSPEND events from the BIOS
1375                          * will be ignored.  We also return here to
1376                          * cope with the fact that the Thinkpads keep
1377                          * sending a SUSPEND event until something else
1378                          * happens!
1379                          */
1380                         if (ignore_sys_suspend)
1381                                 return;
1382                         ignore_sys_suspend = 1;
1383                         queue_event(event, NULL);
1384                         if (suspends_pending <= 0)
1385                                 (void) suspend(1);
1386                         break;
1387 
1388                 case APM_NORMAL_RESUME:
1389                 case APM_CRITICAL_RESUME:
1390                 case APM_STANDBY_RESUME:
1391                         ignore_sys_suspend = 0;
1392                         last_resume = jiffies;
1393                         ignore_bounce = 1;
1394                         if ((event != APM_NORMAL_RESUME)
1395                             || (ignore_normal_resume == 0)) {
1396                                 dpm_resume_end(PMSG_RESUME);
1397                                 queue_event(event, NULL);
1398                         }
1399                         ignore_normal_resume = 0;
1400                         break;
1401 
1402                 case APM_CAPABILITY_CHANGE:
1403                 case APM_LOW_BATTERY:
1404                 case APM_POWER_STATUS_CHANGE:
1405                         queue_event(event, NULL);
1406                         /* If needed, notify drivers here */
1407                         break;
1408 
1409                 case APM_UPDATE_TIME:
1410                         break;
1411 
1412                 case APM_CRITICAL_SUSPEND:
1413                         /*
1414                          * We are not allowed to reject a critical suspend.
1415                          */
1416                         (void)suspend(0);
1417                         break;
1418                 }
1419         }
1420 }
1421 
1422 static void apm_event_handler(void)
1423 {
1424         static int pending_count = 4;
1425         int err;
1426 
1427         if ((standbys_pending > 0) || (suspends_pending > 0)) {
1428                 if ((apm_info.connection_version > 0x100) &&
1429                     (pending_count-- <= 0)) {
1430                         pending_count = 4;
1431                         if (debug)
1432                                 printk(KERN_DEBUG "apm: setting state busy\n");
1433                         err = set_system_power_state(APM_STATE_BUSY);
1434                         if (err)
1435                                 apm_error("busy", err);
1436                 }
1437         } else
1438                 pending_count = 4;
1439         check_events();
1440 }
1441 
1442 /*
1443  * This is the APM thread main loop.
1444  */
1445 
1446 static void apm_mainloop(void)
1447 {
1448         DECLARE_WAITQUEUE(wait, current);
1449 
1450         add_wait_queue(&apm_waitqueue, &wait);
1451         set_current_state(TASK_INTERRUPTIBLE);
1452         for (;;) {
1453                 schedule_timeout(APM_CHECK_TIMEOUT);
1454                 if (kthread_should_stop())
1455                         break;
1456                 /*
1457                  * Ok, check all events, check for idle (and mark us sleeping
1458                  * so as not to count towards the load average)..
1459                  */
1460                 set_current_state(TASK_INTERRUPTIBLE);
1461                 apm_event_handler();
1462         }
1463         remove_wait_queue(&apm_waitqueue, &wait);
1464 }
1465 
1466 static int check_apm_user(struct apm_user *as, const char *func)
1467 {
1468         if (as == NULL || as->magic != APM_BIOS_MAGIC) {
1469                 pr_err("%s passed bad filp\n", func);
1470                 return 1;
1471         }
1472         return 0;
1473 }
1474 
1475 static ssize_t do_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
1476 {
1477         struct apm_user *as;
1478         int i;
1479         apm_event_t event;
1480 
1481         as = fp->private_data;
1482         if (check_apm_user(as, "read"))
1483                 return -EIO;
1484         if ((int)count < sizeof(apm_event_t))
1485                 return -EINVAL;
1486         if ((queue_empty(as)) && (fp->f_flags & O_NONBLOCK))
1487                 return -EAGAIN;
1488         wait_event_interruptible(apm_waitqueue, !queue_empty(as));
1489         i = count;
1490         while ((i >= sizeof(event)) && !queue_empty(as)) {
1491                 event = get_queued_event(as);
1492                 if (copy_to_user(buf, &event, sizeof(event))) {
1493                         if (i < count)
1494                                 break;
1495                         return -EFAULT;
1496                 }
1497                 switch (event) {
1498                 case APM_SYS_SUSPEND:
1499                 case APM_USER_SUSPEND:
1500                         as->suspends_read++;
1501                         break;
1502 
1503                 case APM_SYS_STANDBY:
1504                 case APM_USER_STANDBY:
1505                         as->standbys_read++;
1506                         break;
1507                 }
1508                 buf += sizeof(event);
1509                 i -= sizeof(event);
1510         }
1511         if (i < count)
1512                 return count - i;
1513         if (signal_pending(current))
1514                 return -ERESTARTSYS;
1515         return 0;
1516 }
1517 
1518 static unsigned int do_poll(struct file *fp, poll_table *wait)
1519 {
1520         struct apm_user *as;
1521 
1522         as = fp->private_data;
1523         if (check_apm_user(as, "poll"))
1524                 return 0;
1525         poll_wait(fp, &apm_waitqueue, wait);
1526         if (!queue_empty(as))
1527                 return POLLIN | POLLRDNORM;
1528         return 0;
1529 }
1530 
1531 static long do_ioctl(struct file *filp, u_int cmd, u_long arg)
1532 {
1533         struct apm_user *as;
1534         int ret;
1535 
1536         as = filp->private_data;
1537         if (check_apm_user(as, "ioctl"))
1538                 return -EIO;
1539         if (!as->suser || !as->writer)
1540                 return -EPERM;
1541         switch (cmd) {
1542         case APM_IOC_STANDBY:
1543                 mutex_lock(&apm_mutex);
1544                 if (as->standbys_read > 0) {
1545                         as->standbys_read--;
1546                         as->standbys_pending--;
1547                         standbys_pending--;
1548                 } else
1549                         queue_event(APM_USER_STANDBY, as);
1550                 if (standbys_pending <= 0)
1551                         standby();
1552                 mutex_unlock(&apm_mutex);
1553                 break;
1554         case APM_IOC_SUSPEND:
1555                 mutex_lock(&apm_mutex);
1556                 if (as->suspends_read > 0) {
1557                         as->suspends_read--;
1558                         as->suspends_pending--;
1559                         suspends_pending--;
1560                 } else
1561                         queue_event(APM_USER_SUSPEND, as);
1562                 if (suspends_pending <= 0) {
1563                         ret = suspend(1);
1564                         mutex_unlock(&apm_mutex);
1565                 } else {
1566                         as->suspend_wait = 1;
1567                         mutex_unlock(&apm_mutex);
1568                         wait_event_interruptible(apm_suspend_waitqueue,
1569                                         as->suspend_wait == 0);
1570                         ret = as->suspend_result;
1571                 }
1572                 return ret;
1573         default:
1574                 return -ENOTTY;
1575         }
1576         return 0;
1577 }
1578 
1579 static int do_release(struct inode *inode, struct file *filp)
1580 {
1581         struct apm_user *as;
1582 
1583         as = filp->private_data;
1584         if (check_apm_user(as, "release"))
1585                 return 0;
1586         filp->private_data = NULL;
1587         if (as->standbys_pending > 0) {
1588                 standbys_pending -= as->standbys_pending;
1589                 if (standbys_pending <= 0)
1590                         standby();
1591         }
1592         if (as->suspends_pending > 0) {
1593                 suspends_pending -= as->suspends_pending;
1594                 if (suspends_pending <= 0)
1595                         (void) suspend(1);
1596         }
1597         spin_lock(&user_list_lock);
1598         if (user_list == as)
1599                 user_list = as->next;
1600         else {
1601                 struct apm_user *as1;
1602 
1603                 for (as1 = user_list;
1604                      (as1 != NULL) && (as1->next != as);
1605                      as1 = as1->next)
1606                         ;
1607                 if (as1 == NULL)
1608                         pr_err("filp not in user list\n");
1609                 else
1610                         as1->next = as->next;
1611         }
1612         spin_unlock(&user_list_lock);
1613         kfree(as);
1614         return 0;
1615 }
1616 
1617 static int do_open(struct inode *inode, struct file *filp)
1618 {
1619         struct apm_user *as;
1620 
1621         as = kmalloc(sizeof(*as), GFP_KERNEL);
1622         if (as == NULL)
1623                 return -ENOMEM;
1624 
1625         as->magic = APM_BIOS_MAGIC;
1626         as->event_tail = as->event_head = 0;
1627         as->suspends_pending = as->standbys_pending = 0;
1628         as->suspends_read = as->standbys_read = 0;
1629         /*
1630          * XXX - this is a tiny bit broken, when we consider BSD
1631          * process accounting. If the device is opened by root, we
1632          * instantly flag that we used superuser privs. Who knows,
1633          * we might close the device immediately without doing a
1634          * privileged operation -- cevans
1635          */
1636         as->suser = capable(CAP_SYS_ADMIN);
1637         as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
1638         as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
1639         spin_lock(&user_list_lock);
1640         as->next = user_list;
1641         user_list = as;
1642         spin_unlock(&user_list_lock);
1643         filp->private_data = as;
1644         return 0;
1645 }
1646 
1647 static int proc_apm_show(struct seq_file *m, void *v)
1648 {
1649         unsigned short  bx;
1650         unsigned short  cx;
1651         unsigned short  dx;
1652         int             error;
1653         unsigned short  ac_line_status = 0xff;
1654         unsigned short  battery_status = 0xff;
1655         unsigned short  battery_flag   = 0xff;
1656         int             percentage     = -1;
1657         int             time_units     = -1;
1658         char            *units         = "?";
1659 
1660         if ((num_online_cpus() == 1) &&
1661             !(error = apm_get_power_status(&bx, &cx, &dx))) {
1662                 ac_line_status = (bx >> 8) & 0xff;
1663                 battery_status = bx & 0xff;
1664                 if ((cx & 0xff) != 0xff)
1665                         percentage = cx & 0xff;
1666 
1667                 if (apm_info.connection_version > 0x100) {
1668                         battery_flag = (cx >> 8) & 0xff;
1669                         if (dx != 0xffff) {
1670                                 units = (dx & 0x8000) ? "min" : "sec";
1671                                 time_units = dx & 0x7fff;
1672                         }
1673                 }
1674         }
1675         /* Arguments, with symbols from linux/apm_bios.h.  Information is
1676            from the Get Power Status (0x0a) call unless otherwise noted.
1677 
1678            0) Linux driver version (this will change if format changes)
1679            1) APM BIOS Version.  Usually 1.0, 1.1 or 1.2.
1680            2) APM flags from APM Installation Check (0x00):
1681               bit 0: APM_16_BIT_SUPPORT
1682               bit 1: APM_32_BIT_SUPPORT
1683               bit 2: APM_IDLE_SLOWS_CLOCK
1684               bit 3: APM_BIOS_DISABLED
1685               bit 4: APM_BIOS_DISENGAGED
1686            3) AC line status
1687               0x00: Off-line
1688               0x01: On-line
1689               0x02: On backup power (BIOS >= 1.1 only)
1690               0xff: Unknown
1691            4) Battery status
1692               0x00: High
1693               0x01: Low
1694               0x02: Critical
1695               0x03: Charging
1696               0x04: Selected battery not present (BIOS >= 1.2 only)
1697               0xff: Unknown
1698            5) Battery flag
1699               bit 0: High
1700               bit 1: Low
1701               bit 2: Critical
1702               bit 3: Charging
1703               bit 7: No system battery
1704               0xff: Unknown
1705            6) Remaining battery life (percentage of charge):
1706               0-100: valid
1707               -1: Unknown
1708            7) Remaining battery life (time units):
1709               Number of remaining minutes or seconds
1710               -1: Unknown
1711            8) min = minutes; sec = seconds */
1712 
1713         seq_printf(m, "%s %d.%d 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
1714                    driver_version,
1715                    (apm_info.bios.version >> 8) & 0xff,
1716                    apm_info.bios.version & 0xff,
1717                    apm_info.bios.flags,
1718                    ac_line_status,
1719                    battery_status,
1720                    battery_flag,
1721                    percentage,
1722                    time_units,
1723                    units);
1724         return 0;
1725 }
1726 
1727 static int proc_apm_open(struct inode *inode, struct file *file)
1728 {
1729         return single_open(file, proc_apm_show, NULL);
1730 }
1731 
1732 static const struct file_operations apm_file_ops = {
1733         .owner          = THIS_MODULE,
1734         .open           = proc_apm_open,
1735         .read           = seq_read,
1736         .llseek         = seq_lseek,
1737         .release        = single_release,
1738 };
1739 
1740 static int apm(void *unused)
1741 {
1742         unsigned short  bx;
1743         unsigned short  cx;
1744         unsigned short  dx;
1745         int             error;
1746         char            *power_stat;
1747         char            *bat_stat;
1748 
1749         /* 2002/08/01 - WT
1750          * This is to avoid random crashes at boot time during initialization
1751          * on SMP systems in case of "apm=power-off" mode. Seen on ASUS A7M266D.
1752          * Some bioses don't like being called from CPU != 0.
1753          * Method suggested by Ingo Molnar.
1754          */
1755         set_cpus_allowed_ptr(current, cpumask_of(0));
1756         BUG_ON(smp_processor_id() != 0);
1757 
1758         if (apm_info.connection_version == 0) {
1759                 apm_info.connection_version = apm_info.bios.version;
1760                 if (apm_info.connection_version > 0x100) {
1761                         /*
1762                          * We only support BIOSs up to version 1.2
1763                          */
1764                         if (apm_info.connection_version > 0x0102)
1765                                 apm_info.connection_version = 0x0102;
1766                         error = apm_driver_version(&apm_info.connection_version);
1767                         if (error != APM_SUCCESS) {
1768                                 apm_error("driver version", error);
1769                                 /* Fall back to an APM 1.0 connection. */
1770                                 apm_info.connection_version = 0x100;
1771                         }
1772                 }
1773         }
1774 
1775         if (debug)
1776                 printk(KERN_INFO "apm: Connection version %d.%d\n",
1777                         (apm_info.connection_version >> 8) & 0xff,
1778                         apm_info.connection_version & 0xff);
1779 
1780 #ifdef CONFIG_APM_DO_ENABLE
1781         if (apm_info.bios.flags & APM_BIOS_DISABLED) {
1782                 /*
1783                  * This call causes my NEC UltraLite Versa 33/C to hang if it
1784                  * is booted with PM disabled but not in the docking station.
1785                  * Unfortunate ...
1786                  */
1787                 error = apm_enable_power_management(1);
1788                 if (error) {
1789                         apm_error("enable power management", error);
1790                         return -1;
1791                 }
1792         }
1793 #endif
1794 
1795         if ((apm_info.bios.flags & APM_BIOS_DISENGAGED)
1796             && (apm_info.connection_version > 0x0100)) {
1797                 error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1798                 if (error) {
1799                         apm_error("engage power management", error);
1800                         return -1;
1801                 }
1802         }
1803 
1804         if (debug && (num_online_cpus() == 1 || smp)) {
1805                 error = apm_get_power_status(&bx, &cx, &dx);
1806                 if (error)
1807                         printk(KERN_INFO "apm: power status not available\n");
1808                 else {
1809                         switch ((bx >> 8) & 0xff) {
1810                         case 0:
1811                                 power_stat = "off line";
1812                                 break;
1813                         case 1:
1814                                 power_stat = "on line";
1815                                 break;
1816                         case 2:
1817                                 power_stat = "on backup power";
1818                                 break;
1819                         default:
1820                                 power_stat = "unknown";
1821                                 break;
1822                         }
1823                         switch (bx & 0xff) {
1824                         case 0:
1825                                 bat_stat = "high";
1826                                 break;
1827                         case 1:
1828                                 bat_stat = "low";
1829                                 break;
1830                         case 2:
1831                                 bat_stat = "critical";
1832                                 break;
1833                         case 3:
1834                                 bat_stat = "charging";
1835                                 break;
1836                         default:
1837                                 bat_stat = "unknown";
1838                                 break;
1839                         }
1840                         printk(KERN_INFO
1841                                "apm: AC %s, battery status %s, battery life ",
1842                                power_stat, bat_stat);
1843                         if ((cx & 0xff) == 0xff)
1844                                 printk("unknown\n");
1845                         else
1846                                 printk("%d%%\n", cx & 0xff);
1847                         if (apm_info.connection_version > 0x100) {
1848                                 printk(KERN_INFO
1849                                        "apm: battery flag 0x%02x, battery life ",
1850                                        (cx >> 8) & 0xff);
1851                                 if (dx == 0xffff)
1852                                         printk("unknown\n");
1853                                 else
1854                                         printk("%d %s\n", dx & 0x7fff,
1855                                                (dx & 0x8000) ?
1856                                                "minutes" : "seconds");
1857                         }
1858                 }
1859         }
1860 
1861         /* Install our power off handler.. */
1862         if (power_off)
1863                 pm_power_off = apm_power_off;
1864 
1865         if (num_online_cpus() == 1 || smp) {
1866 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1867                 console_blank_hook = apm_console_blank;
1868 #endif
1869                 apm_mainloop();
1870 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1871                 console_blank_hook = NULL;
1872 #endif
1873         }
1874 
1875         return 0;
1876 }
1877 
1878 #ifndef MODULE
1879 static int __init apm_setup(char *str)
1880 {
1881         int invert;
1882 
1883         while ((str != NULL) && (*str != '\0')) {
1884                 if (strncmp(str, "off", 3) == 0)
1885                         apm_disabled = 1;
1886                 if (strncmp(str, "on", 2) == 0)
1887                         apm_disabled = 0;
1888                 if ((strncmp(str, "bounce-interval=", 16) == 0) ||
1889                     (strncmp(str, "bounce_interval=", 16) == 0))
1890                         bounce_interval = simple_strtol(str + 16, NULL, 0);
1891                 if ((strncmp(str, "idle-threshold=", 15) == 0) ||
1892                     (strncmp(str, "idle_threshold=", 15) == 0))
1893                         idle_threshold = simple_strtol(str + 15, NULL, 0);
1894                 if ((strncmp(str, "idle-period=", 12) == 0) ||
1895                     (strncmp(str, "idle_period=", 12) == 0))
1896                         idle_period = simple_strtol(str + 12, NULL, 0);
1897                 invert = (strncmp(str, "no-", 3) == 0) ||
1898                         (strncmp(str, "no_", 3) == 0);
1899                 if (invert)
1900                         str += 3;
1901                 if (strncmp(str, "debug", 5) == 0)
1902                         debug = !invert;
1903                 if ((strncmp(str, "power-off", 9) == 0) ||
1904                     (strncmp(str, "power_off", 9) == 0))
1905                         power_off = !invert;
1906                 if (strncmp(str, "smp", 3) == 0) {
1907                         smp = !invert;
1908                         idle_threshold = 100;
1909                 }
1910                 if ((strncmp(str, "allow-ints", 10) == 0) ||
1911                     (strncmp(str, "allow_ints", 10) == 0))
1912                         apm_info.allow_ints = !invert;
1913                 if ((strncmp(str, "broken-psr", 10) == 0) ||
1914                     (strncmp(str, "broken_psr", 10) == 0))
1915                         apm_info.get_power_status_broken = !invert;
1916                 if ((strncmp(str, "realmode-power-off", 18) == 0) ||
1917                     (strncmp(str, "realmode_power_off", 18) == 0))
1918                         apm_info.realmode_power_off = !invert;
1919                 str = strchr(str, ',');
1920                 if (str != NULL)
1921                         str += strspn(str, ", \t");
1922         }
1923         return 1;
1924 }
1925 
1926 __setup("apm=", apm_setup);
1927 #endif
1928 
1929 static const struct file_operations apm_bios_fops = {
1930         .owner          = THIS_MODULE,
1931         .read           = do_read,
1932         .poll           = do_poll,
1933         .unlocked_ioctl = do_ioctl,
1934         .open           = do_open,
1935         .release        = do_release,
1936         .llseek         = noop_llseek,
1937 };
1938 
1939 static struct miscdevice apm_device = {
1940         APM_MINOR_DEV,
1941         "apm_bios",
1942         &apm_bios_fops
1943 };
1944 
1945 
1946 /* Simple "print if true" callback */
1947 static int __init print_if_true(const struct dmi_system_id *d)
1948 {
1949         printk("%s\n", d->ident);
1950         return 0;
1951 }
1952 
1953 /*
1954  * Some Bioses enable the PS/2 mouse (touchpad) at resume, even if it was
1955  * disabled before the suspend. Linux used to get terribly confused by that.
1956  */
1957 static int __init broken_ps2_resume(const struct dmi_system_id *d)
1958 {
1959         printk(KERN_INFO "%s machine detected. Mousepad Resume Bug "
1960                "workaround hopefully not needed.\n", d->ident);
1961         return 0;
1962 }
1963 
1964 /* Some bioses have a broken protected mode poweroff and need to use realmode */
1965 static int __init set_realmode_power_off(const struct dmi_system_id *d)
1966 {
1967         if (apm_info.realmode_power_off == 0) {
1968                 apm_info.realmode_power_off = 1;
1969                 printk(KERN_INFO "%s bios detected. "
1970                        "Using realmode poweroff only.\n", d->ident);
1971         }
1972         return 0;
1973 }
1974 
1975 /* Some laptops require interrupts to be enabled during APM calls */
1976 static int __init set_apm_ints(const struct dmi_system_id *d)
1977 {
1978         if (apm_info.allow_ints == 0) {
1979                 apm_info.allow_ints = 1;
1980                 printk(KERN_INFO "%s machine detected. "
1981                        "Enabling interrupts during APM calls.\n", d->ident);
1982         }
1983         return 0;
1984 }
1985 
1986 /* Some APM bioses corrupt memory or just plain do not work */
1987 static int __init apm_is_horked(const struct dmi_system_id *d)
1988 {
1989         if (apm_info.disabled == 0) {
1990                 apm_info.disabled = 1;
1991                 printk(KERN_INFO "%s machine detected. "
1992                        "Disabling APM.\n", d->ident);
1993         }
1994         return 0;
1995 }
1996 
1997 static int __init apm_is_horked_d850md(const struct dmi_system_id *d)
1998 {
1999         if (apm_info.disabled == 0) {
2000                 apm_info.disabled = 1;
2001                 printk(KERN_INFO "%s machine detected. "
2002                        "Disabling APM.\n", d->ident);
2003                 printk(KERN_INFO "This bug is fixed in bios P15 which is available for\n");
2004                 printk(KERN_INFO "download from support.intel.com\n");
2005         }
2006         return 0;
2007 }
2008 
2009 /* Some APM bioses hang on APM idle calls */
2010 static int __init apm_likes_to_melt(const struct dmi_system_id *d)
2011 {
2012         if (apm_info.forbid_idle == 0) {
2013                 apm_info.forbid_idle = 1;
2014                 printk(KERN_INFO "%s machine detected. "
2015                        "Disabling APM idle calls.\n", d->ident);
2016         }
2017         return 0;
2018 }
2019 
2020 /*
2021  *  Check for clue free BIOS implementations who use
2022  *  the following QA technique
2023  *
2024  *      [ Write BIOS Code ]<------
2025  *               |                ^
2026  *      < Does it Compile >----N--
2027  *               |Y               ^
2028  *      < Does it Boot Win98 >-N--
2029  *               |Y
2030  *           [Ship It]
2031  *
2032  *      Phoenix A04  08/24/2000 is known bad (Dell Inspiron 5000e)
2033  *      Phoenix A07  09/29/2000 is known good (Dell Inspiron 5000)
2034  */
2035 static int __init broken_apm_power(const struct dmi_system_id *d)
2036 {
2037         apm_info.get_power_status_broken = 1;
2038         printk(KERN_WARNING "BIOS strings suggest APM bugs, "
2039                "disabling power status reporting.\n");
2040         return 0;
2041 }
2042 
2043 /*
2044  * This bios swaps the APM minute reporting bytes over (Many sony laptops
2045  * have this problem).
2046  */
2047 static int __init swab_apm_power_in_minutes(const struct dmi_system_id *d)
2048 {
2049         apm_info.get_power_status_swabinminutes = 1;
2050         printk(KERN_WARNING "BIOS strings suggest APM reports battery life "
2051                "in minutes and wrong byte order.\n");
2052         return 0;
2053 }
2054 
2055 static struct dmi_system_id __initdata apm_dmi_table[] = {
2056         {
2057                 print_if_true,
2058                 KERN_WARNING "IBM T23 - BIOS 1.03b+ and controller firmware 1.02+ may be needed for Linux APM.",
2059                 {       DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
2060                         DMI_MATCH(DMI_BIOS_VERSION, "1AET38WW (1.01b)"), },
2061         },
2062         {       /* Handle problems with APM on the C600 */
2063                 broken_ps2_resume, "Dell Latitude C600",
2064                 {       DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
2065                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C600"), },
2066         },
2067         {       /* Allow interrupts during suspend on Dell Latitude laptops*/
2068                 set_apm_ints, "Dell Latitude",
2069                 {       DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2070                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C510"), }
2071         },
2072         {       /* APM crashes */
2073                 apm_is_horked, "Dell Inspiron 2500",
2074                 {       DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2075                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2076                         DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2077                         DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2078         },
2079         {       /* Allow interrupts during suspend on Dell Inspiron laptops*/
2080                 set_apm_ints, "Dell Inspiron", {
2081                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2082                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 4000"), },
2083         },
2084         {       /* Handle problems with APM on Inspiron 5000e */
2085                 broken_apm_power, "Dell Inspiron 5000e",
2086                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2087                         DMI_MATCH(DMI_BIOS_VERSION, "A04"),
2088                         DMI_MATCH(DMI_BIOS_DATE, "08/24/2000"), },
2089         },
2090         {       /* Handle problems with APM on Inspiron 2500 */
2091                 broken_apm_power, "Dell Inspiron 2500",
2092                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2093                         DMI_MATCH(DMI_BIOS_VERSION, "A12"),
2094                         DMI_MATCH(DMI_BIOS_DATE, "02/04/2002"), },
2095         },
2096         {       /* APM crashes */
2097                 apm_is_horked, "Dell Dimension 4100",
2098                 {       DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2099                         DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"),
2100                         DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2101                         DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2102         },
2103         {       /* Allow interrupts during suspend on Compaq Laptops*/
2104                 set_apm_ints, "Compaq 12XL125",
2105                 {       DMI_MATCH(DMI_SYS_VENDOR, "Compaq"),
2106                         DMI_MATCH(DMI_PRODUCT_NAME, "Compaq PC"),
2107                         DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2108                         DMI_MATCH(DMI_BIOS_VERSION, "4.06"), },
2109         },
2110         {       /* Allow interrupts during APM or the clock goes slow */
2111                 set_apm_ints, "ASUSTeK",
2112                 {       DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
2113                         DMI_MATCH(DMI_PRODUCT_NAME, "L8400K series Notebook PC"), },
2114         },
2115         {       /* APM blows on shutdown */
2116                 apm_is_horked, "ABIT KX7-333[R]",
2117                 {       DMI_MATCH(DMI_BOARD_VENDOR, "ABIT"),
2118                         DMI_MATCH(DMI_BOARD_NAME, "VT8367-8233A (KX7-333[R])"), },
2119         },
2120         {       /* APM crashes */
2121                 apm_is_horked, "Trigem Delhi3",
2122                 {       DMI_MATCH(DMI_SYS_VENDOR, "TriGem Computer, Inc"),
2123                         DMI_MATCH(DMI_PRODUCT_NAME, "Delhi3"), },
2124         },
2125         {       /* APM crashes */
2126                 apm_is_horked, "Fujitsu-Siemens",
2127                 {       DMI_MATCH(DMI_BIOS_VENDOR, "hoenix/FUJITSU SIEMENS"),
2128                         DMI_MATCH(DMI_BIOS_VERSION, "Version1.01"), },
2129         },
2130         {       /* APM crashes */
2131                 apm_is_horked_d850md, "Intel D850MD",
2132                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2133                         DMI_MATCH(DMI_BIOS_VERSION, "MV85010A.86A.0016.P07.0201251536"), },
2134         },
2135         {       /* APM crashes */
2136                 apm_is_horked, "Intel D810EMO",
2137                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2138                         DMI_MATCH(DMI_BIOS_VERSION, "MO81010A.86A.0008.P04.0004170800"), },
2139         },
2140         {       /* APM crashes */
2141                 apm_is_horked, "Dell XPS-Z",
2142                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2143                         DMI_MATCH(DMI_BIOS_VERSION, "A11"),
2144                         DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"), },
2145         },
2146         {       /* APM crashes */
2147                 apm_is_horked, "Sharp PC-PJ/AX",
2148                 {       DMI_MATCH(DMI_SYS_VENDOR, "SHARP"),
2149                         DMI_MATCH(DMI_PRODUCT_NAME, "PC-PJ/AX"),
2150                         DMI_MATCH(DMI_BIOS_VENDOR, "SystemSoft"),
2151                         DMI_MATCH(DMI_BIOS_VERSION, "Version R2.08"), },
2152         },
2153         {       /* APM crashes */
2154                 apm_is_horked, "Dell Inspiron 2500",
2155                 {       DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2156                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2157                         DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2158                         DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2159         },
2160         {       /* APM idle hangs */
2161                 apm_likes_to_melt, "Jabil AMD",
2162                 {       DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2163                         DMI_MATCH(DMI_BIOS_VERSION, "0AASNP06"), },
2164         },
2165         {       /* APM idle hangs */
2166                 apm_likes_to_melt, "AMI Bios",
2167                 {       DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2168                         DMI_MATCH(DMI_BIOS_VERSION, "0AASNP05"), },
2169         },
2170         {       /* Handle problems with APM on Sony Vaio PCG-N505X(DE) */
2171                 swab_apm_power_in_minutes, "Sony VAIO",
2172                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2173                         DMI_MATCH(DMI_BIOS_VERSION, "R0206H"),
2174                         DMI_MATCH(DMI_BIOS_DATE, "08/23/99"), },
2175         },
2176         {       /* Handle problems with APM on Sony Vaio PCG-N505VX */
2177                 swab_apm_power_in_minutes, "Sony VAIO",
2178                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2179                         DMI_MATCH(DMI_BIOS_VERSION, "W2K06H0"),
2180                         DMI_MATCH(DMI_BIOS_DATE, "02/03/00"), },
2181         },
2182         {       /* Handle problems with APM on Sony Vaio PCG-XG29 */
2183                 swab_apm_power_in_minutes, "Sony VAIO",
2184                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2185                         DMI_MATCH(DMI_BIOS_VERSION, "R0117A0"),
2186                         DMI_MATCH(DMI_BIOS_DATE, "04/25/00"), },
2187         },
2188         {       /* Handle problems with APM on Sony Vaio PCG-Z600NE */
2189                 swab_apm_power_in_minutes, "Sony VAIO",
2190                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2191                         DMI_MATCH(DMI_BIOS_VERSION, "R0121Z1"),
2192                         DMI_MATCH(DMI_BIOS_DATE, "05/11/00"), },
2193         },
2194         {       /* Handle problems with APM on Sony Vaio PCG-Z600NE */
2195                 swab_apm_power_in_minutes, "Sony VAIO",
2196                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2197                         DMI_MATCH(DMI_BIOS_VERSION, "WME01Z1"),
2198                         DMI_MATCH(DMI_BIOS_DATE, "08/11/00"), },
2199         },
2200         {       /* Handle problems with APM on Sony Vaio PCG-Z600LEK(DE) */
2201                 swab_apm_power_in_minutes, "Sony VAIO",
2202                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2203                         DMI_MATCH(DMI_BIOS_VERSION, "R0206Z3"),
2204                         DMI_MATCH(DMI_BIOS_DATE, "12/25/00"), },
2205         },
2206         {       /* Handle problems with APM on Sony Vaio PCG-Z505LS */
2207                 swab_apm_power_in_minutes, "Sony VAIO",
2208                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2209                         DMI_MATCH(DMI_BIOS_VERSION, "R0203D0"),
2210                         DMI_MATCH(DMI_BIOS_DATE, "05/12/00"), },
2211         },
2212         {       /* Handle problems with APM on Sony Vaio PCG-Z505LS */
2213                 swab_apm_power_in_minutes, "Sony VAIO",
2214                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2215                         DMI_MATCH(DMI_BIOS_VERSION, "R0203Z3"),
2216                         DMI_MATCH(DMI_BIOS_DATE, "08/25/00"), },
2217         },
2218         {       /* Handle problems with APM on Sony Vaio PCG-Z505LS (with updated BIOS) */
2219                 swab_apm_power_in_minutes, "Sony VAIO",
2220                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2221                         DMI_MATCH(DMI_BIOS_VERSION, "R0209Z3"),
2222                         DMI_MATCH(DMI_BIOS_DATE, "05/12/01"), },
2223         },
2224         {       /* Handle problems with APM on Sony Vaio PCG-F104K */
2225                 swab_apm_power_in_minutes, "Sony VAIO",
2226                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2227                         DMI_MATCH(DMI_BIOS_VERSION, "R0204K2"),
2228                         DMI_MATCH(DMI_BIOS_DATE, "08/28/00"), },
2229         },
2230 
2231         {       /* Handle problems with APM on Sony Vaio PCG-C1VN/C1VE */
2232                 swab_apm_power_in_minutes, "Sony VAIO",
2233                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2234                         DMI_MATCH(DMI_BIOS_VERSION, "R0208P1"),
2235                         DMI_MATCH(DMI_BIOS_DATE, "11/09/00"), },
2236         },
2237         {       /* Handle problems with APM on Sony Vaio PCG-C1VE */
2238                 swab_apm_power_in_minutes, "Sony VAIO",
2239                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2240                         DMI_MATCH(DMI_BIOS_VERSION, "R0204P1"),
2241                         DMI_MATCH(DMI_BIOS_DATE, "09/12/00"), },
2242         },
2243         {       /* Handle problems with APM on Sony Vaio PCG-C1VE */
2244                 swab_apm_power_in_minutes, "Sony VAIO",
2245                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2246                         DMI_MATCH(DMI_BIOS_VERSION, "WXPO1Z3"),
2247                         DMI_MATCH(DMI_BIOS_DATE, "10/26/01"), },
2248         },
2249         {       /* broken PM poweroff bios */
2250                 set_realmode_power_off, "Award Software v4.60 PGMA",
2251                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Award Software International, Inc."),
2252                         DMI_MATCH(DMI_BIOS_VERSION, "4.60 PGMA"),
2253                         DMI_MATCH(DMI_BIOS_DATE, "134526184"), },
2254         },
2255 
2256         /* Generic per vendor APM settings  */
2257 
2258         {       /* Allow interrupts during suspend on IBM laptops */
2259                 set_apm_ints, "IBM",
2260                 {       DMI_MATCH(DMI_SYS_VENDOR, "IBM"), },
2261         },
2262 
2263         { }
2264 };
2265 
2266 /*
2267  * Just start the APM thread. We do NOT want to do APM BIOS
2268  * calls from anything but the APM thread, if for no other reason
2269  * than the fact that we don't trust the APM BIOS. This way,
2270  * most common APM BIOS problems that lead to protection errors
2271  * etc will have at least some level of being contained...
2272  *
2273  * In short, if something bad happens, at least we have a choice
2274  * of just killing the apm thread..
2275  */
2276 static int __init apm_init(void)
2277 {
2278         struct desc_struct *gdt;
2279         int err;
2280 
2281         dmi_check_system(apm_dmi_table);
2282 
2283         if (apm_info.bios.version == 0 || paravirt_enabled() || machine_is_olpc()) {
2284                 printk(KERN_INFO "apm: BIOS not found.\n");
2285                 return -ENODEV;
2286         }
2287         printk(KERN_INFO
2288                "apm: BIOS version %d.%d Flags 0x%02x (Driver version %s)\n",
2289                ((apm_info.bios.version >> 8) & 0xff),
2290                (apm_info.bios.version & 0xff),
2291                apm_info.bios.flags,
2292                driver_version);
2293         if ((apm_info.bios.flags & APM_32_BIT_SUPPORT) == 0) {
2294                 printk(KERN_INFO "apm: no 32 bit BIOS support\n");
2295                 return -ENODEV;
2296         }
2297 
2298         if (allow_ints)
2299                 apm_info.allow_ints = 1;
2300         if (broken_psr)
2301                 apm_info.get_power_status_broken = 1;
2302         if (realmode_power_off)
2303                 apm_info.realmode_power_off = 1;
2304         /* User can override, but default is to trust DMI */
2305         if (apm_disabled != -1)
2306                 apm_info.disabled = apm_disabled;
2307 
2308         /*
2309          * Fix for the Compaq Contura 3/25c which reports BIOS version 0.1
2310          * but is reportedly a 1.0 BIOS.
2311          */
2312         if (apm_info.bios.version == 0x001)
2313                 apm_info.bios.version = 0x100;
2314 
2315         /* BIOS < 1.2 doesn't set cseg_16_len */
2316         if (apm_info.bios.version < 0x102)
2317                 apm_info.bios.cseg_16_len = 0; /* 64k */
2318 
2319         if (debug) {
2320                 printk(KERN_INFO "apm: entry %x:%x cseg16 %x dseg %x",
2321                         apm_info.bios.cseg, apm_info.bios.offset,
2322                         apm_info.bios.cseg_16, apm_info.bios.dseg);
2323                 if (apm_info.bios.version > 0x100)
2324                         printk(" cseg len %x, dseg len %x",
2325                                 apm_info.bios.cseg_len,
2326                                 apm_info.bios.dseg_len);
2327                 if (apm_info.bios.version > 0x101)
2328                         printk(" cseg16 len %x", apm_info.bios.cseg_16_len);
2329                 printk("\n");
2330         }
2331 
2332         if (apm_info.disabled) {
2333                 pr_notice("disabled on user request.\n");
2334                 return -ENODEV;
2335         }
2336         if ((num_online_cpus() > 1) && !power_off && !smp) {
2337                 pr_notice("disabled - APM is not SMP safe.\n");
2338                 apm_info.disabled = 1;
2339                 return -ENODEV;
2340         }
2341         if (!acpi_disabled) {
2342                 pr_notice("overridden by ACPI.\n");
2343                 apm_info.disabled = 1;
2344                 return -ENODEV;
2345         }
2346 
2347         /*
2348          * Set up the long jump entry point to the APM BIOS, which is called
2349          * from inline assembly.
2350          */
2351         apm_bios_entry.offset = apm_info.bios.offset;
2352         apm_bios_entry.segment = APM_CS;
2353 
2354         /*
2355          * The APM 1.1 BIOS is supposed to provide limit information that it
2356          * recognizes.  Many machines do this correctly, but many others do
2357          * not restrict themselves to their claimed limit.  When this happens,
2358          * they will cause a segmentation violation in the kernel at boot time.
2359          * Most BIOS's, however, will respect a 64k limit, so we use that.
2360          *
2361          * Note we only set APM segments on CPU zero, since we pin the APM
2362          * code to that CPU.
2363          */
2364         gdt = get_cpu_gdt_table(0);
2365         set_desc_base(&gdt[APM_CS >> 3],
2366                  (unsigned long)__va((unsigned long)apm_info.bios.cseg << 4));
2367         set_desc_base(&gdt[APM_CS_16 >> 3],
2368                  (unsigned long)__va((unsigned long)apm_info.bios.cseg_16 << 4));
2369         set_desc_base(&gdt[APM_DS >> 3],
2370                  (unsigned long)__va((unsigned long)apm_info.bios.dseg << 4));
2371 
2372         proc_create("apm", 0, NULL, &apm_file_ops);
2373 
2374         kapmd_task = kthread_create(apm, NULL, "kapmd");
2375         if (IS_ERR(kapmd_task)) {
2376                 pr_err("disabled - Unable to start kernel thread\n");
2377                 err = PTR_ERR(kapmd_task);
2378                 kapmd_task = NULL;
2379                 remove_proc_entry("apm", NULL);
2380                 return err;
2381         }
2382         wake_up_process(kapmd_task);
2383 
2384         if (num_online_cpus() > 1 && !smp) {
2385                 printk(KERN_NOTICE
2386                        "apm: disabled - APM is not SMP safe (power off active).\n");
2387                 return 0;
2388         }
2389 
2390         /*
2391          * Note we don't actually care if the misc_device cannot be registered.
2392          * this driver can do its job without it, even if userspace can't
2393          * control it.  just log the error
2394          */
2395         if (misc_register(&apm_device))
2396                 printk(KERN_WARNING "apm: Could not register misc device.\n");
2397 
2398         if (HZ != 100)
2399                 idle_period = (idle_period * HZ) / 100;
2400         if (idle_threshold < 100) {
2401                 if (!cpuidle_register_driver(&apm_idle_driver))
2402                         if (cpuidle_register_device(&apm_cpuidle_device))
2403                                 cpuidle_unregister_driver(&apm_idle_driver);
2404         }
2405 
2406         return 0;
2407 }
2408 
2409 static void __exit apm_exit(void)
2410 {
2411         int error;
2412 
2413         cpuidle_unregister_device(&apm_cpuidle_device);
2414         cpuidle_unregister_driver(&apm_idle_driver);
2415 
2416         if (((apm_info.bios.flags & APM_BIOS_DISENGAGED) == 0)
2417             && (apm_info.connection_version > 0x0100)) {
2418                 error = apm_engage_power_management(APM_DEVICE_ALL, 0);
2419                 if (error)
2420                         apm_error("disengage power management", error);
2421         }
2422         misc_deregister(&apm_device);
2423         remove_proc_entry("apm", NULL);
2424         if (power_off)
2425                 pm_power_off = NULL;
2426         if (kapmd_task) {
2427                 kthread_stop(kapmd_task);
2428                 kapmd_task = NULL;
2429         }
2430 }
2431 
2432 module_init(apm_init);
2433 module_exit(apm_exit);
2434 
2435 MODULE_AUTHOR("Stephen Rothwell");
2436 MODULE_DESCRIPTION("Advanced Power Management");
2437 MODULE_LICENSE("GPL");
2438 module_param(debug, bool, 0644);
2439 MODULE_PARM_DESC(debug, "Enable debug mode");
2440 module_param(power_off, bool, 0444);
2441 MODULE_PARM_DESC(power_off, "Enable power off");
2442 module_param(bounce_interval, int, 0444);
2443 MODULE_PARM_DESC(bounce_interval,
2444                 "Set the number of ticks to ignore suspend bounces");
2445 module_param(allow_ints, bool, 0444);
2446 MODULE_PARM_DESC(allow_ints, "Allow interrupts during BIOS calls");
2447 module_param(broken_psr, bool, 0444);
2448 MODULE_PARM_DESC(broken_psr, "BIOS has a broken GetPowerStatus call");
2449 module_param(realmode_power_off, bool, 0444);
2450 MODULE_PARM_DESC(realmode_power_off,
2451                 "Switch to real mode before powering off");
2452 module_param(idle_threshold, int, 0444);
2453 MODULE_PARM_DESC(idle_threshold,
2454         "System idle percentage above which to make APM BIOS idle calls");
2455 module_param(idle_period, int, 0444);
2456 MODULE_PARM_DESC(idle_period,
2457         "Period (in sec/100) over which to caculate the idle percentage");
2458 module_param(smp, bool, 0444);
2459 MODULE_PARM_DESC(smp,
2460         "Set this to enable APM use on an SMP platform. Use with caution on older systems");
2461 MODULE_ALIAS_MISCDEV(APM_MINOR_DEV);
2462 

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