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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/signal.h>
222 #include <linux/sched/cputime.h>
223 #include <linux/pm.h>
224 #include <linux/capability.h>
225 #include <linux/device.h>
226 #include <linux/kernel.h>
227 #include <linux/freezer.h>
228 #include <linux/smp.h>
229 #include <linux/dmi.h>
230 #include <linux/suspend.h>
231 #include <linux/kthread.h>
232 #include <linux/jiffies.h>
233 #include <linux/acpi.h>
234 #include <linux/syscore_ops.h>
235 #include <linux/i8253.h>
236 #include <linux/cpuidle.h>
237 
238 #include <linux/uaccess.h>
239 #include <asm/desc.h>
240 #include <asm/olpc.h>
241 #include <asm/paravirt.h>
242 #include <asm/reboot.h>
243 
244 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
245 extern int (*console_blank_hook)(int);
246 #endif
247 
248 /*
249  * The apm_bios device is one of the misc char devices.
250  * This is its minor number.
251  */
252 #define APM_MINOR_DEV   134
253 
254 /*
255  * Various options can be changed at boot time as follows:
256  * (We allow underscores for compatibility with the modules code)
257  *      apm=on/off                      enable/disable APM
258  *          [no-]allow[-_]ints          allow interrupts during BIOS calls
259  *          [no-]broken[-_]psr          BIOS has a broken GetPowerStatus call
260  *          [no-]realmode[-_]power[-_]off       switch to real mode before
261  *                                              powering off
262  *          [no-]debug                  log some debugging messages
263  *          [no-]power[-_]off           power off on shutdown
264  *          [no-]smp                    Use apm even on an SMP box
265  *          bounce[-_]interval=<n>      number of ticks to ignore suspend
266  *                                      bounces
267  *          idle[-_]threshold=<n>       System idle percentage above which to
268  *                                      make APM BIOS idle calls. Set it to
269  *                                      100 to disable.
270  *          idle[-_]period=<n>          Period (in 1/100s of a second) over
271  *                                      which the idle percentage is
272  *                                      calculated.
273  */
274 
275 /* KNOWN PROBLEM MACHINES:
276  *
277  * U: TI 4000M TravelMate: BIOS is *NOT* APM compliant
278  *                         [Confirmed by TI representative]
279  * ?: ACER 486DX4/75: uses dseg 0040, in violation of APM specification
280  *                    [Confirmed by BIOS disassembly]
281  *                    [This may work now ...]
282  * P: Toshiba 1950S: battery life information only gets updated after resume
283  * P: Midwest Micro Soundbook Elite DX2/66 monochrome: screen blanking
284  *      broken in BIOS [Reported by Garst R. Reese <reese@isn.net>]
285  * ?: AcerNote-950: oops on reading /proc/apm - workaround is a WIP
286  *      Neale Banks <neale@lowendale.com.au> December 2000
287  *
288  * Legend: U = unusable with APM patches
289  *         P = partially usable with APM patches
290  */
291 
292 /*
293  * Define as 1 to make the driver always call the APM BIOS busy
294  * routine even if the clock was not reported as slowed by the
295  * idle routine.  Otherwise, define as 0.
296  */
297 #define ALWAYS_CALL_BUSY   1
298 
299 /*
300  * Define to make the APM BIOS calls zero all data segment registers (so
301  * that an incorrect BIOS implementation will cause a kernel panic if it
302  * tries to write to arbitrary memory).
303  */
304 #define APM_ZERO_SEGS
305 
306 #include <asm/apm.h>
307 
308 /*
309  * Define to re-initialize the interrupt 0 timer to 100 Hz after a suspend.
310  * This patched by Chad Miller <cmiller@surfsouth.com>, original code by
311  * David Chen <chen@ctpa04.mit.edu>
312  */
313 #undef INIT_TIMER_AFTER_SUSPEND
314 
315 #ifdef INIT_TIMER_AFTER_SUSPEND
316 #include <linux/timex.h>
317 #include <asm/io.h>
318 #include <linux/delay.h>
319 #endif
320 
321 /*
322  * Need to poll the APM BIOS every second
323  */
324 #define APM_CHECK_TIMEOUT       (HZ)
325 
326 /*
327  * Ignore suspend events for this amount of time after a resume
328  */
329 #define DEFAULT_BOUNCE_INTERVAL (3 * HZ)
330 
331 /*
332  * Maximum number of events stored
333  */
334 #define APM_MAX_EVENTS          20
335 
336 /*
337  * The per-file APM data
338  */
339 struct apm_user {
340         int             magic;
341         struct apm_user *next;
342         unsigned int    suser: 1;
343         unsigned int    writer: 1;
344         unsigned int    reader: 1;
345         unsigned int    suspend_wait: 1;
346         int             suspend_result;
347         int             suspends_pending;
348         int             standbys_pending;
349         int             suspends_read;
350         int             standbys_read;
351         int             event_head;
352         int             event_tail;
353         apm_event_t     events[APM_MAX_EVENTS];
354 };
355 
356 /*
357  * The magic number in apm_user
358  */
359 #define APM_BIOS_MAGIC          0x4101
360 
361 /*
362  * idle percentage above which bios idle calls are done
363  */
364 #ifdef CONFIG_APM_CPU_IDLE
365 #define DEFAULT_IDLE_THRESHOLD  95
366 #else
367 #define DEFAULT_IDLE_THRESHOLD  100
368 #endif
369 #define DEFAULT_IDLE_PERIOD     (100 / 3)
370 
371 static int apm_cpu_idle(struct cpuidle_device *dev,
372                         struct cpuidle_driver *drv, int index);
373 
374 static struct cpuidle_driver apm_idle_driver = {
375         .name = "apm_idle",
376         .owner = THIS_MODULE,
377         .states = {
378                 { /* entry 0 is for polling */ },
379                 { /* entry 1 is for APM idle */
380                         .name = "APM",
381                         .desc = "APM idle",
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 __visible 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_rw(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_rw(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 err = 0;
845 
846         if (!need_resched()) {
847                 idled = 1;
848                 ret = apm_bios_call_simple(APM_FUNC_IDLE, 0, 0, &eax, &err);
849         }
850 
851         if (!idled)
852                 return 0;
853 
854         if (ret) {
855                 static unsigned long t;
856 
857                 /* This always fails on some SMP boards running UP kernels.
858                  * Only report the failure the first 5 times.
859                  */
860                 if (++t < 5) {
861                         printk(KERN_DEBUG "apm_do_idle failed (%d)\n", err);
862                         t = jiffies;
863                 }
864                 return -1;
865         }
866         clock_slowed = (apm_info.bios.flags & APM_IDLE_SLOWS_CLOCK) != 0;
867         return clock_slowed;
868 }
869 
870 /**
871  *      apm_do_busy     -       inform the BIOS the CPU is busy
872  *
873  *      Request that the BIOS brings the CPU back to full performance.
874  */
875 
876 static void apm_do_busy(void)
877 {
878         u32 dummy;
879         int err;
880 
881         if (clock_slowed || ALWAYS_CALL_BUSY) {
882                 (void)apm_bios_call_simple(APM_FUNC_BUSY, 0, 0, &dummy, &err);
883                 clock_slowed = 0;
884         }
885 }
886 
887 /*
888  * If no process has really been interested in
889  * the CPU for some time, we want to call BIOS
890  * power management - we probably want
891  * to conserve power.
892  */
893 #define IDLE_CALC_LIMIT (HZ * 100)
894 #define IDLE_LEAKY_MAX  16
895 
896 /**
897  * apm_cpu_idle         -       cpu idling for APM capable Linux
898  *
899  * This is the idling function the kernel executes when APM is available. It
900  * tries to do BIOS powermanagement based on the average system idle time.
901  * Furthermore it calls the system default idle routine.
902  */
903 
904 static int apm_cpu_idle(struct cpuidle_device *dev,
905         struct cpuidle_driver *drv, int index)
906 {
907         static int use_apm_idle; /* = 0 */
908         static unsigned int last_jiffies; /* = 0 */
909         static u64 last_stime; /* = 0 */
910         u64 stime, utime;
911 
912         int apm_idle_done = 0;
913         unsigned int jiffies_since_last_check = jiffies - last_jiffies;
914         unsigned int bucket;
915 
916 recalc:
917         task_cputime(current, &utime, &stime);
918         if (jiffies_since_last_check > IDLE_CALC_LIMIT) {
919                 use_apm_idle = 0;
920         } else if (jiffies_since_last_check > idle_period) {
921                 unsigned int idle_percentage;
922 
923                 idle_percentage = nsecs_to_jiffies(stime - last_stime);
924                 idle_percentage *= 100;
925                 idle_percentage /= jiffies_since_last_check;
926                 use_apm_idle = (idle_percentage > idle_threshold);
927                 if (apm_info.forbid_idle)
928                         use_apm_idle = 0;
929         }
930 
931         last_jiffies = jiffies;
932         last_stime = stime;
933 
934         bucket = IDLE_LEAKY_MAX;
935 
936         while (!need_resched()) {
937                 if (use_apm_idle) {
938                         unsigned int t;
939 
940                         t = jiffies;
941                         switch (apm_do_idle()) {
942                         case 0:
943                                 apm_idle_done = 1;
944                                 if (t != jiffies) {
945                                         if (bucket) {
946                                                 bucket = IDLE_LEAKY_MAX;
947                                                 continue;
948                                         }
949                                 } else if (bucket) {
950                                         bucket--;
951                                         continue;
952                                 }
953                                 break;
954                         case 1:
955                                 apm_idle_done = 1;
956                                 break;
957                         default: /* BIOS refused */
958                                 break;
959                         }
960                 }
961                 default_idle();
962                 local_irq_disable();
963                 jiffies_since_last_check = jiffies - last_jiffies;
964                 if (jiffies_since_last_check > idle_period)
965                         goto recalc;
966         }
967 
968         if (apm_idle_done)
969                 apm_do_busy();
970 
971         return index;
972 }
973 
974 /**
975  *      apm_power_off   -       ask the BIOS to power off
976  *
977  *      Handle the power off sequence. This is the one piece of code we
978  *      will execute even on SMP machines. In order to deal with BIOS
979  *      bugs we support real mode APM BIOS power off calls. We also make
980  *      the SMP call on CPU0 as some systems will only honour this call
981  *      on their first cpu.
982  */
983 
984 static void apm_power_off(void)
985 {
986         /* Some bioses don't like being called from CPU != 0 */
987         if (apm_info.realmode_power_off) {
988                 set_cpus_allowed_ptr(current, cpumask_of(0));
989                 machine_real_restart(MRR_APM);
990         } else {
991                 (void)set_system_power_state(APM_STATE_OFF);
992         }
993 }
994 
995 #ifdef CONFIG_APM_DO_ENABLE
996 
997 /**
998  *      apm_enable_power_management - enable BIOS APM power management
999  *      @enable: enable yes/no
1000  *
1001  *      Enable or disable the APM BIOS power services.
1002  */
1003 
1004 static int apm_enable_power_management(int enable)
1005 {
1006         u32 eax;
1007         int err;
1008 
1009         if ((enable == 0) && (apm_info.bios.flags & APM_BIOS_DISENGAGED))
1010                 return APM_NOT_ENGAGED;
1011         if (apm_bios_call_simple(APM_FUNC_ENABLE_PM, APM_DEVICE_BALL,
1012                                  enable, &eax, &err))
1013                 return err;
1014         if (enable)
1015                 apm_info.bios.flags &= ~APM_BIOS_DISABLED;
1016         else
1017                 apm_info.bios.flags |= APM_BIOS_DISABLED;
1018         return APM_SUCCESS;
1019 }
1020 #endif
1021 
1022 /**
1023  *      apm_get_power_status    -       get current power state
1024  *      @status: returned status
1025  *      @bat: battery info
1026  *      @life: estimated life
1027  *
1028  *      Obtain the current power status from the APM BIOS. We return a
1029  *      status which gives the rough battery status, and current power
1030  *      source. The bat value returned give an estimate as a percentage
1031  *      of life and a status value for the battery. The estimated life
1032  *      if reported is a lifetime in secodnds/minutes at current powwer
1033  *      consumption.
1034  */
1035 
1036 static int apm_get_power_status(u_short *status, u_short *bat, u_short *life)
1037 {
1038         struct apm_bios_call call;
1039 
1040         call.func = APM_FUNC_GET_STATUS;
1041         call.ebx = APM_DEVICE_ALL;
1042         call.ecx = 0;
1043 
1044         if (apm_info.get_power_status_broken)
1045                 return APM_32_UNSUPPORTED;
1046         if (apm_bios_call(&call)) {
1047                 if (!call.err)
1048                         return APM_NO_ERROR;
1049                 return call.err;
1050         }
1051         *status = call.ebx;
1052         *bat = call.ecx;
1053         if (apm_info.get_power_status_swabinminutes) {
1054                 *life = swab16((u16)call.edx);
1055                 *life |= 0x8000;
1056         } else
1057                 *life = call.edx;
1058         return APM_SUCCESS;
1059 }
1060 
1061 #if 0
1062 static int apm_get_battery_status(u_short which, u_short *status,
1063                                   u_short *bat, u_short *life, u_short *nbat)
1064 {
1065         u32 eax;
1066         u32 ebx;
1067         u32 ecx;
1068         u32 edx;
1069         u32 esi;
1070 
1071         if (apm_info.connection_version < 0x0102) {
1072                 /* pretend we only have one battery. */
1073                 if (which != 1)
1074                         return APM_BAD_DEVICE;
1075                 *nbat = 1;
1076                 return apm_get_power_status(status, bat, life);
1077         }
1078 
1079         if (apm_bios_call(APM_FUNC_GET_STATUS, (0x8000 | (which)), 0, &eax,
1080                           &ebx, &ecx, &edx, &esi))
1081                 return (eax >> 8) & 0xff;
1082         *status = ebx;
1083         *bat = ecx;
1084         *life = edx;
1085         *nbat = esi;
1086         return APM_SUCCESS;
1087 }
1088 #endif
1089 
1090 /**
1091  *      apm_engage_power_management     -       enable PM on a device
1092  *      @device: identity of device
1093  *      @enable: on/off
1094  *
1095  *      Activate or deactivate power management on either a specific device
1096  *      or the entire system (%APM_DEVICE_ALL).
1097  */
1098 
1099 static int apm_engage_power_management(u_short device, int enable)
1100 {
1101         u32 eax;
1102         int err;
1103 
1104         if ((enable == 0) && (device == APM_DEVICE_ALL)
1105             && (apm_info.bios.flags & APM_BIOS_DISABLED))
1106                 return APM_DISABLED;
1107         if (apm_bios_call_simple(APM_FUNC_ENGAGE_PM, device, enable,
1108                                  &eax, &err))
1109                 return err;
1110         if (device == APM_DEVICE_ALL) {
1111                 if (enable)
1112                         apm_info.bios.flags &= ~APM_BIOS_DISENGAGED;
1113                 else
1114                         apm_info.bios.flags |= APM_BIOS_DISENGAGED;
1115         }
1116         return APM_SUCCESS;
1117 }
1118 
1119 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1120 
1121 /**
1122  *      apm_console_blank       -       blank the display
1123  *      @blank: on/off
1124  *
1125  *      Attempt to blank the console, firstly by blanking just video device
1126  *      zero, and if that fails (some BIOSes don't support it) then it blanks
1127  *      all video devices. Typically the BIOS will do laptop backlight and
1128  *      monitor powerdown for us.
1129  */
1130 
1131 static int apm_console_blank(int blank)
1132 {
1133         int error = APM_NOT_ENGAGED; /* silence gcc */
1134         int i;
1135         u_short state;
1136         static const u_short dev[3] = { 0x100, 0x1FF, 0x101 };
1137 
1138         state = blank ? APM_STATE_STANDBY : APM_STATE_READY;
1139 
1140         for (i = 0; i < ARRAY_SIZE(dev); i++) {
1141                 error = set_power_state(dev[i], state);
1142 
1143                 if ((error == APM_SUCCESS) || (error == APM_NO_ERROR))
1144                         return 1;
1145 
1146                 if (error == APM_NOT_ENGAGED)
1147                         break;
1148         }
1149 
1150         if (error == APM_NOT_ENGAGED) {
1151                 static int tried;
1152                 int eng_error;
1153                 if (tried++ == 0) {
1154                         eng_error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1155                         if (eng_error) {
1156                                 apm_error("set display", error);
1157                                 apm_error("engage interface", eng_error);
1158                                 return 0;
1159                         } else
1160                                 return apm_console_blank(blank);
1161                 }
1162         }
1163         apm_error("set display", error);
1164         return 0;
1165 }
1166 #endif
1167 
1168 static int queue_empty(struct apm_user *as)
1169 {
1170         return as->event_head == as->event_tail;
1171 }
1172 
1173 static apm_event_t get_queued_event(struct apm_user *as)
1174 {
1175         if (++as->event_tail >= APM_MAX_EVENTS)
1176                 as->event_tail = 0;
1177         return as->events[as->event_tail];
1178 }
1179 
1180 static void queue_event(apm_event_t event, struct apm_user *sender)
1181 {
1182         struct apm_user *as;
1183 
1184         spin_lock(&user_list_lock);
1185         if (user_list == NULL)
1186                 goto out;
1187         for (as = user_list; as != NULL; as = as->next) {
1188                 if ((as == sender) || (!as->reader))
1189                         continue;
1190                 if (++as->event_head >= APM_MAX_EVENTS)
1191                         as->event_head = 0;
1192 
1193                 if (as->event_head == as->event_tail) {
1194                         static int notified;
1195 
1196                         if (notified++ == 0)
1197                                 pr_err("an event queue overflowed\n");
1198                         if (++as->event_tail >= APM_MAX_EVENTS)
1199                                 as->event_tail = 0;
1200                 }
1201                 as->events[as->event_head] = event;
1202                 if (!as->suser || !as->writer)
1203                         continue;
1204                 switch (event) {
1205                 case APM_SYS_SUSPEND:
1206                 case APM_USER_SUSPEND:
1207                         as->suspends_pending++;
1208                         suspends_pending++;
1209                         break;
1210 
1211                 case APM_SYS_STANDBY:
1212                 case APM_USER_STANDBY:
1213                         as->standbys_pending++;
1214                         standbys_pending++;
1215                         break;
1216                 }
1217         }
1218         wake_up_interruptible(&apm_waitqueue);
1219 out:
1220         spin_unlock(&user_list_lock);
1221 }
1222 
1223 static void reinit_timer(void)
1224 {
1225 #ifdef INIT_TIMER_AFTER_SUSPEND
1226         unsigned long flags;
1227 
1228         raw_spin_lock_irqsave(&i8253_lock, flags);
1229         /* set the clock to HZ */
1230         outb_p(0x34, PIT_MODE);         /* binary, mode 2, LSB/MSB, ch 0 */
1231         udelay(10);
1232         outb_p(LATCH & 0xff, PIT_CH0);  /* LSB */
1233         udelay(10);
1234         outb_p(LATCH >> 8, PIT_CH0);    /* MSB */
1235         udelay(10);
1236         raw_spin_unlock_irqrestore(&i8253_lock, flags);
1237 #endif
1238 }
1239 
1240 static int suspend(int vetoable)
1241 {
1242         int err;
1243         struct apm_user *as;
1244 
1245         dpm_suspend_start(PMSG_SUSPEND);
1246         dpm_suspend_end(PMSG_SUSPEND);
1247 
1248         local_irq_disable();
1249         syscore_suspend();
1250 
1251         local_irq_enable();
1252 
1253         save_processor_state();
1254         err = set_system_power_state(APM_STATE_SUSPEND);
1255         ignore_normal_resume = 1;
1256         restore_processor_state();
1257 
1258         local_irq_disable();
1259         reinit_timer();
1260 
1261         if (err == APM_NO_ERROR)
1262                 err = APM_SUCCESS;
1263         if (err != APM_SUCCESS)
1264                 apm_error("suspend", err);
1265         err = (err == APM_SUCCESS) ? 0 : -EIO;
1266 
1267         syscore_resume();
1268         local_irq_enable();
1269 
1270         dpm_resume_start(PMSG_RESUME);
1271         dpm_resume_end(PMSG_RESUME);
1272 
1273         queue_event(APM_NORMAL_RESUME, NULL);
1274         spin_lock(&user_list_lock);
1275         for (as = user_list; as != NULL; as = as->next) {
1276                 as->suspend_wait = 0;
1277                 as->suspend_result = err;
1278         }
1279         spin_unlock(&user_list_lock);
1280         wake_up_interruptible(&apm_suspend_waitqueue);
1281         return err;
1282 }
1283 
1284 static void standby(void)
1285 {
1286         int err;
1287 
1288         dpm_suspend_end(PMSG_SUSPEND);
1289 
1290         local_irq_disable();
1291         syscore_suspend();
1292         local_irq_enable();
1293 
1294         err = set_system_power_state(APM_STATE_STANDBY);
1295         if ((err != APM_SUCCESS) && (err != APM_NO_ERROR))
1296                 apm_error("standby", err);
1297 
1298         local_irq_disable();
1299         syscore_resume();
1300         local_irq_enable();
1301 
1302         dpm_resume_start(PMSG_RESUME);
1303 }
1304 
1305 static apm_event_t get_event(void)
1306 {
1307         int error;
1308         apm_event_t event = APM_NO_EVENTS; /* silence gcc */
1309         apm_eventinfo_t info;
1310 
1311         static int notified;
1312 
1313         /* we don't use the eventinfo */
1314         error = apm_get_event(&event, &info);
1315         if (error == APM_SUCCESS)
1316                 return event;
1317 
1318         if ((error != APM_NO_EVENTS) && (notified++ == 0))
1319                 apm_error("get_event", error);
1320 
1321         return 0;
1322 }
1323 
1324 static void check_events(void)
1325 {
1326         apm_event_t event;
1327         static unsigned long last_resume;
1328         static int ignore_bounce;
1329 
1330         while ((event = get_event()) != 0) {
1331                 if (debug) {
1332                         if (event <= NR_APM_EVENT_NAME)
1333                                 printk(KERN_DEBUG "apm: received %s notify\n",
1334                                        apm_event_name[event - 1]);
1335                         else
1336                                 printk(KERN_DEBUG "apm: received unknown "
1337                                        "event 0x%02x\n", event);
1338                 }
1339                 if (ignore_bounce
1340                     && (time_after(jiffies, last_resume + bounce_interval)))
1341                         ignore_bounce = 0;
1342 
1343                 switch (event) {
1344                 case APM_SYS_STANDBY:
1345                 case APM_USER_STANDBY:
1346                         queue_event(event, NULL);
1347                         if (standbys_pending <= 0)
1348                                 standby();
1349                         break;
1350 
1351                 case APM_USER_SUSPEND:
1352 #ifdef CONFIG_APM_IGNORE_USER_SUSPEND
1353                         if (apm_info.connection_version > 0x100)
1354                                 set_system_power_state(APM_STATE_REJECT);
1355                         break;
1356 #endif
1357                 case APM_SYS_SUSPEND:
1358                         if (ignore_bounce) {
1359                                 if (apm_info.connection_version > 0x100)
1360                                         set_system_power_state(APM_STATE_REJECT);
1361                                 break;
1362                         }
1363                         /*
1364                          * If we are already processing a SUSPEND,
1365                          * then further SUSPEND events from the BIOS
1366                          * will be ignored.  We also return here to
1367                          * cope with the fact that the Thinkpads keep
1368                          * sending a SUSPEND event until something else
1369                          * happens!
1370                          */
1371                         if (ignore_sys_suspend)
1372                                 return;
1373                         ignore_sys_suspend = 1;
1374                         queue_event(event, NULL);
1375                         if (suspends_pending <= 0)
1376                                 (void) suspend(1);
1377                         break;
1378 
1379                 case APM_NORMAL_RESUME:
1380                 case APM_CRITICAL_RESUME:
1381                 case APM_STANDBY_RESUME:
1382                         ignore_sys_suspend = 0;
1383                         last_resume = jiffies;
1384                         ignore_bounce = 1;
1385                         if ((event != APM_NORMAL_RESUME)
1386                             || (ignore_normal_resume == 0)) {
1387                                 dpm_resume_end(PMSG_RESUME);
1388                                 queue_event(event, NULL);
1389                         }
1390                         ignore_normal_resume = 0;
1391                         break;
1392 
1393                 case APM_CAPABILITY_CHANGE:
1394                 case APM_LOW_BATTERY:
1395                 case APM_POWER_STATUS_CHANGE:
1396                         queue_event(event, NULL);
1397                         /* If needed, notify drivers here */
1398                         break;
1399 
1400                 case APM_UPDATE_TIME:
1401                         break;
1402 
1403                 case APM_CRITICAL_SUSPEND:
1404                         /*
1405                          * We are not allowed to reject a critical suspend.
1406                          */
1407                         (void)suspend(0);
1408                         break;
1409                 }
1410         }
1411 }
1412 
1413 static void apm_event_handler(void)
1414 {
1415         static int pending_count = 4;
1416         int err;
1417 
1418         if ((standbys_pending > 0) || (suspends_pending > 0)) {
1419                 if ((apm_info.connection_version > 0x100) &&
1420                     (pending_count-- <= 0)) {
1421                         pending_count = 4;
1422                         if (debug)
1423                                 printk(KERN_DEBUG "apm: setting state busy\n");
1424                         err = set_system_power_state(APM_STATE_BUSY);
1425                         if (err)
1426                                 apm_error("busy", err);
1427                 }
1428         } else
1429                 pending_count = 4;
1430         check_events();
1431 }
1432 
1433 /*
1434  * This is the APM thread main loop.
1435  */
1436 
1437 static void apm_mainloop(void)
1438 {
1439         DECLARE_WAITQUEUE(wait, current);
1440 
1441         add_wait_queue(&apm_waitqueue, &wait);
1442         set_current_state(TASK_INTERRUPTIBLE);
1443         for (;;) {
1444                 schedule_timeout(APM_CHECK_TIMEOUT);
1445                 if (kthread_should_stop())
1446                         break;
1447                 /*
1448                  * Ok, check all events, check for idle (and mark us sleeping
1449                  * so as not to count towards the load average)..
1450                  */
1451                 set_current_state(TASK_INTERRUPTIBLE);
1452                 apm_event_handler();
1453         }
1454         remove_wait_queue(&apm_waitqueue, &wait);
1455 }
1456 
1457 static int check_apm_user(struct apm_user *as, const char *func)
1458 {
1459         if (as == NULL || as->magic != APM_BIOS_MAGIC) {
1460                 pr_err("%s passed bad filp\n", func);
1461                 return 1;
1462         }
1463         return 0;
1464 }
1465 
1466 static ssize_t do_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
1467 {
1468         struct apm_user *as;
1469         int i;
1470         apm_event_t event;
1471 
1472         as = fp->private_data;
1473         if (check_apm_user(as, "read"))
1474                 return -EIO;
1475         if ((int)count < sizeof(apm_event_t))
1476                 return -EINVAL;
1477         if ((queue_empty(as)) && (fp->f_flags & O_NONBLOCK))
1478                 return -EAGAIN;
1479         wait_event_interruptible(apm_waitqueue, !queue_empty(as));
1480         i = count;
1481         while ((i >= sizeof(event)) && !queue_empty(as)) {
1482                 event = get_queued_event(as);
1483                 if (copy_to_user(buf, &event, sizeof(event))) {
1484                         if (i < count)
1485                                 break;
1486                         return -EFAULT;
1487                 }
1488                 switch (event) {
1489                 case APM_SYS_SUSPEND:
1490                 case APM_USER_SUSPEND:
1491                         as->suspends_read++;
1492                         break;
1493 
1494                 case APM_SYS_STANDBY:
1495                 case APM_USER_STANDBY:
1496                         as->standbys_read++;
1497                         break;
1498                 }
1499                 buf += sizeof(event);
1500                 i -= sizeof(event);
1501         }
1502         if (i < count)
1503                 return count - i;
1504         if (signal_pending(current))
1505                 return -ERESTARTSYS;
1506         return 0;
1507 }
1508 
1509 static __poll_t do_poll(struct file *fp, poll_table *wait)
1510 {
1511         struct apm_user *as;
1512 
1513         as = fp->private_data;
1514         if (check_apm_user(as, "poll"))
1515                 return 0;
1516         poll_wait(fp, &apm_waitqueue, wait);
1517         if (!queue_empty(as))
1518                 return EPOLLIN | EPOLLRDNORM;
1519         return 0;
1520 }
1521 
1522 static long do_ioctl(struct file *filp, u_int cmd, u_long arg)
1523 {
1524         struct apm_user *as;
1525         int ret;
1526 
1527         as = filp->private_data;
1528         if (check_apm_user(as, "ioctl"))
1529                 return -EIO;
1530         if (!as->suser || !as->writer)
1531                 return -EPERM;
1532         switch (cmd) {
1533         case APM_IOC_STANDBY:
1534                 mutex_lock(&apm_mutex);
1535                 if (as->standbys_read > 0) {
1536                         as->standbys_read--;
1537                         as->standbys_pending--;
1538                         standbys_pending--;
1539                 } else
1540                         queue_event(APM_USER_STANDBY, as);
1541                 if (standbys_pending <= 0)
1542                         standby();
1543                 mutex_unlock(&apm_mutex);
1544                 break;
1545         case APM_IOC_SUSPEND:
1546                 mutex_lock(&apm_mutex);
1547                 if (as->suspends_read > 0) {
1548                         as->suspends_read--;
1549                         as->suspends_pending--;
1550                         suspends_pending--;
1551                 } else
1552                         queue_event(APM_USER_SUSPEND, as);
1553                 if (suspends_pending <= 0) {
1554                         ret = suspend(1);
1555                         mutex_unlock(&apm_mutex);
1556                 } else {
1557                         as->suspend_wait = 1;
1558                         mutex_unlock(&apm_mutex);
1559                         wait_event_interruptible(apm_suspend_waitqueue,
1560                                         as->suspend_wait == 0);
1561                         ret = as->suspend_result;
1562                 }
1563                 return ret;
1564         default:
1565                 return -ENOTTY;
1566         }
1567         return 0;
1568 }
1569 
1570 static int do_release(struct inode *inode, struct file *filp)
1571 {
1572         struct apm_user *as;
1573 
1574         as = filp->private_data;
1575         if (check_apm_user(as, "release"))
1576                 return 0;
1577         filp->private_data = NULL;
1578         if (as->standbys_pending > 0) {
1579                 standbys_pending -= as->standbys_pending;
1580                 if (standbys_pending <= 0)
1581                         standby();
1582         }
1583         if (as->suspends_pending > 0) {
1584                 suspends_pending -= as->suspends_pending;
1585                 if (suspends_pending <= 0)
1586                         (void) suspend(1);
1587         }
1588         spin_lock(&user_list_lock);
1589         if (user_list == as)
1590                 user_list = as->next;
1591         else {
1592                 struct apm_user *as1;
1593 
1594                 for (as1 = user_list;
1595                      (as1 != NULL) && (as1->next != as);
1596                      as1 = as1->next)
1597                         ;
1598                 if (as1 == NULL)
1599                         pr_err("filp not in user list\n");
1600                 else
1601                         as1->next = as->next;
1602         }
1603         spin_unlock(&user_list_lock);
1604         kfree(as);
1605         return 0;
1606 }
1607 
1608 static int do_open(struct inode *inode, struct file *filp)
1609 {
1610         struct apm_user *as;
1611 
1612         as = kmalloc(sizeof(*as), GFP_KERNEL);
1613         if (as == NULL)
1614                 return -ENOMEM;
1615 
1616         as->magic = APM_BIOS_MAGIC;
1617         as->event_tail = as->event_head = 0;
1618         as->suspends_pending = as->standbys_pending = 0;
1619         as->suspends_read = as->standbys_read = 0;
1620         /*
1621          * XXX - this is a tiny bit broken, when we consider BSD
1622          * process accounting. If the device is opened by root, we
1623          * instantly flag that we used superuser privs. Who knows,
1624          * we might close the device immediately without doing a
1625          * privileged operation -- cevans
1626          */
1627         as->suser = capable(CAP_SYS_ADMIN);
1628         as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
1629         as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
1630         spin_lock(&user_list_lock);
1631         as->next = user_list;
1632         user_list = as;
1633         spin_unlock(&user_list_lock);
1634         filp->private_data = as;
1635         return 0;
1636 }
1637 
1638 static int proc_apm_show(struct seq_file *m, void *v)
1639 {
1640         unsigned short  bx;
1641         unsigned short  cx;
1642         unsigned short  dx;
1643         int             error;
1644         unsigned short  ac_line_status = 0xff;
1645         unsigned short  battery_status = 0xff;
1646         unsigned short  battery_flag   = 0xff;
1647         int             percentage     = -1;
1648         int             time_units     = -1;
1649         char            *units         = "?";
1650 
1651         if ((num_online_cpus() == 1) &&
1652             !(error = apm_get_power_status(&bx, &cx, &dx))) {
1653                 ac_line_status = (bx >> 8) & 0xff;
1654                 battery_status = bx & 0xff;
1655                 if ((cx & 0xff) != 0xff)
1656                         percentage = cx & 0xff;
1657 
1658                 if (apm_info.connection_version > 0x100) {
1659                         battery_flag = (cx >> 8) & 0xff;
1660                         if (dx != 0xffff) {
1661                                 units = (dx & 0x8000) ? "min" : "sec";
1662                                 time_units = dx & 0x7fff;
1663                         }
1664                 }
1665         }
1666         /* Arguments, with symbols from linux/apm_bios.h.  Information is
1667            from the Get Power Status (0x0a) call unless otherwise noted.
1668 
1669            0) Linux driver version (this will change if format changes)
1670            1) APM BIOS Version.  Usually 1.0, 1.1 or 1.2.
1671            2) APM flags from APM Installation Check (0x00):
1672               bit 0: APM_16_BIT_SUPPORT
1673               bit 1: APM_32_BIT_SUPPORT
1674               bit 2: APM_IDLE_SLOWS_CLOCK
1675               bit 3: APM_BIOS_DISABLED
1676               bit 4: APM_BIOS_DISENGAGED
1677            3) AC line status
1678               0x00: Off-line
1679               0x01: On-line
1680               0x02: On backup power (BIOS >= 1.1 only)
1681               0xff: Unknown
1682            4) Battery status
1683               0x00: High
1684               0x01: Low
1685               0x02: Critical
1686               0x03: Charging
1687               0x04: Selected battery not present (BIOS >= 1.2 only)
1688               0xff: Unknown
1689            5) Battery flag
1690               bit 0: High
1691               bit 1: Low
1692               bit 2: Critical
1693               bit 3: Charging
1694               bit 7: No system battery
1695               0xff: Unknown
1696            6) Remaining battery life (percentage of charge):
1697               0-100: valid
1698               -1: Unknown
1699            7) Remaining battery life (time units):
1700               Number of remaining minutes or seconds
1701               -1: Unknown
1702            8) min = minutes; sec = seconds */
1703 
1704         seq_printf(m, "%s %d.%d 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
1705                    driver_version,
1706                    (apm_info.bios.version >> 8) & 0xff,
1707                    apm_info.bios.version & 0xff,
1708                    apm_info.bios.flags,
1709                    ac_line_status,
1710                    battery_status,
1711                    battery_flag,
1712                    percentage,
1713                    time_units,
1714                    units);
1715         return 0;
1716 }
1717 
1718 static int proc_apm_open(struct inode *inode, struct file *file)
1719 {
1720         return single_open(file, proc_apm_show, NULL);
1721 }
1722 
1723 static const struct file_operations apm_file_ops = {
1724         .owner          = THIS_MODULE,
1725         .open           = proc_apm_open,
1726         .read           = seq_read,
1727         .llseek         = seq_lseek,
1728         .release        = single_release,
1729 };
1730 
1731 static int apm(void *unused)
1732 {
1733         unsigned short  bx;
1734         unsigned short  cx;
1735         unsigned short  dx;
1736         int             error;
1737         char            *power_stat;
1738         char            *bat_stat;
1739 
1740         /* 2002/08/01 - WT
1741          * This is to avoid random crashes at boot time during initialization
1742          * on SMP systems in case of "apm=power-off" mode. Seen on ASUS A7M266D.
1743          * Some bioses don't like being called from CPU != 0.
1744          * Method suggested by Ingo Molnar.
1745          */
1746         set_cpus_allowed_ptr(current, cpumask_of(0));
1747         BUG_ON(smp_processor_id() != 0);
1748 
1749         if (apm_info.connection_version == 0) {
1750                 apm_info.connection_version = apm_info.bios.version;
1751                 if (apm_info.connection_version > 0x100) {
1752                         /*
1753                          * We only support BIOSs up to version 1.2
1754                          */
1755                         if (apm_info.connection_version > 0x0102)
1756                                 apm_info.connection_version = 0x0102;
1757                         error = apm_driver_version(&apm_info.connection_version);
1758                         if (error != APM_SUCCESS) {
1759                                 apm_error("driver version", error);
1760                                 /* Fall back to an APM 1.0 connection. */
1761                                 apm_info.connection_version = 0x100;
1762                         }
1763                 }
1764         }
1765 
1766         if (debug)
1767                 printk(KERN_INFO "apm: Connection version %d.%d\n",
1768                         (apm_info.connection_version >> 8) & 0xff,
1769                         apm_info.connection_version & 0xff);
1770 
1771 #ifdef CONFIG_APM_DO_ENABLE
1772         if (apm_info.bios.flags & APM_BIOS_DISABLED) {
1773                 /*
1774                  * This call causes my NEC UltraLite Versa 33/C to hang if it
1775                  * is booted with PM disabled but not in the docking station.
1776                  * Unfortunate ...
1777                  */
1778                 error = apm_enable_power_management(1);
1779                 if (error) {
1780                         apm_error("enable power management", error);
1781                         return -1;
1782                 }
1783         }
1784 #endif
1785 
1786         if ((apm_info.bios.flags & APM_BIOS_DISENGAGED)
1787             && (apm_info.connection_version > 0x0100)) {
1788                 error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1789                 if (error) {
1790                         apm_error("engage power management", error);
1791                         return -1;
1792                 }
1793         }
1794 
1795         if (debug && (num_online_cpus() == 1 || smp)) {
1796                 error = apm_get_power_status(&bx, &cx, &dx);
1797                 if (error)
1798                         printk(KERN_INFO "apm: power status not available\n");
1799                 else {
1800                         switch ((bx >> 8) & 0xff) {
1801                         case 0:
1802                                 power_stat = "off line";
1803                                 break;
1804                         case 1:
1805                                 power_stat = "on line";
1806                                 break;
1807                         case 2:
1808                                 power_stat = "on backup power";
1809                                 break;
1810                         default:
1811                                 power_stat = "unknown";
1812                                 break;
1813                         }
1814                         switch (bx & 0xff) {
1815                         case 0:
1816                                 bat_stat = "high";
1817                                 break;
1818                         case 1:
1819                                 bat_stat = "low";
1820                                 break;
1821                         case 2:
1822                                 bat_stat = "critical";
1823                                 break;
1824                         case 3:
1825                                 bat_stat = "charging";
1826                                 break;
1827                         default:
1828                                 bat_stat = "unknown";
1829                                 break;
1830                         }
1831                         printk(KERN_INFO
1832                                "apm: AC %s, battery status %s, battery life ",
1833                                power_stat, bat_stat);
1834                         if ((cx & 0xff) == 0xff)
1835                                 printk("unknown\n");
1836                         else
1837                                 printk("%d%%\n", cx & 0xff);
1838                         if (apm_info.connection_version > 0x100) {
1839                                 printk(KERN_INFO
1840                                        "apm: battery flag 0x%02x, battery life ",
1841                                        (cx >> 8) & 0xff);
1842                                 if (dx == 0xffff)
1843                                         printk("unknown\n");
1844                                 else
1845                                         printk("%d %s\n", dx & 0x7fff,
1846                                                (dx & 0x8000) ?
1847                                                "minutes" : "seconds");
1848                         }
1849                 }
1850         }
1851 
1852         /* Install our power off handler.. */
1853         if (power_off)
1854                 pm_power_off = apm_power_off;
1855 
1856         if (num_online_cpus() == 1 || smp) {
1857 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1858                 console_blank_hook = apm_console_blank;
1859 #endif
1860                 apm_mainloop();
1861 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1862                 console_blank_hook = NULL;
1863 #endif
1864         }
1865 
1866         return 0;
1867 }
1868 
1869 #ifndef MODULE
1870 static int __init apm_setup(char *str)
1871 {
1872         int invert;
1873 
1874         while ((str != NULL) && (*str != '\0')) {
1875                 if (strncmp(str, "off", 3) == 0)
1876                         apm_disabled = 1;
1877                 if (strncmp(str, "on", 2) == 0)
1878                         apm_disabled = 0;
1879                 if ((strncmp(str, "bounce-interval=", 16) == 0) ||
1880                     (strncmp(str, "bounce_interval=", 16) == 0))
1881                         bounce_interval = simple_strtol(str + 16, NULL, 0);
1882                 if ((strncmp(str, "idle-threshold=", 15) == 0) ||
1883                     (strncmp(str, "idle_threshold=", 15) == 0))
1884                         idle_threshold = simple_strtol(str + 15, NULL, 0);
1885                 if ((strncmp(str, "idle-period=", 12) == 0) ||
1886                     (strncmp(str, "idle_period=", 12) == 0))
1887                         idle_period = simple_strtol(str + 12, NULL, 0);
1888                 invert = (strncmp(str, "no-", 3) == 0) ||
1889                         (strncmp(str, "no_", 3) == 0);
1890                 if (invert)
1891                         str += 3;
1892                 if (strncmp(str, "debug", 5) == 0)
1893                         debug = !invert;
1894                 if ((strncmp(str, "power-off", 9) == 0) ||
1895                     (strncmp(str, "power_off", 9) == 0))
1896                         power_off = !invert;
1897                 if (strncmp(str, "smp", 3) == 0) {
1898                         smp = !invert;
1899                         idle_threshold = 100;
1900                 }
1901                 if ((strncmp(str, "allow-ints", 10) == 0) ||
1902                     (strncmp(str, "allow_ints", 10) == 0))
1903                         apm_info.allow_ints = !invert;
1904                 if ((strncmp(str, "broken-psr", 10) == 0) ||
1905                     (strncmp(str, "broken_psr", 10) == 0))
1906                         apm_info.get_power_status_broken = !invert;
1907                 if ((strncmp(str, "realmode-power-off", 18) == 0) ||
1908                     (strncmp(str, "realmode_power_off", 18) == 0))
1909                         apm_info.realmode_power_off = !invert;
1910                 str = strchr(str, ',');
1911                 if (str != NULL)
1912                         str += strspn(str, ", \t");
1913         }
1914         return 1;
1915 }
1916 
1917 __setup("apm=", apm_setup);
1918 #endif
1919 
1920 static const struct file_operations apm_bios_fops = {
1921         .owner          = THIS_MODULE,
1922         .read           = do_read,
1923         .poll           = do_poll,
1924         .unlocked_ioctl = do_ioctl,
1925         .open           = do_open,
1926         .release        = do_release,
1927         .llseek         = noop_llseek,
1928 };
1929 
1930 static struct miscdevice apm_device = {
1931         APM_MINOR_DEV,
1932         "apm_bios",
1933         &apm_bios_fops
1934 };
1935 
1936 
1937 /* Simple "print if true" callback */
1938 static int __init print_if_true(const struct dmi_system_id *d)
1939 {
1940         printk("%s\n", d->ident);
1941         return 0;
1942 }
1943 
1944 /*
1945  * Some Bioses enable the PS/2 mouse (touchpad) at resume, even if it was
1946  * disabled before the suspend. Linux used to get terribly confused by that.
1947  */
1948 static int __init broken_ps2_resume(const struct dmi_system_id *d)
1949 {
1950         printk(KERN_INFO "%s machine detected. Mousepad Resume Bug "
1951                "workaround hopefully not needed.\n", d->ident);
1952         return 0;
1953 }
1954 
1955 /* Some bioses have a broken protected mode poweroff and need to use realmode */
1956 static int __init set_realmode_power_off(const struct dmi_system_id *d)
1957 {
1958         if (apm_info.realmode_power_off == 0) {
1959                 apm_info.realmode_power_off = 1;
1960                 printk(KERN_INFO "%s bios detected. "
1961                        "Using realmode poweroff only.\n", d->ident);
1962         }
1963         return 0;
1964 }
1965 
1966 /* Some laptops require interrupts to be enabled during APM calls */
1967 static int __init set_apm_ints(const struct dmi_system_id *d)
1968 {
1969         if (apm_info.allow_ints == 0) {
1970                 apm_info.allow_ints = 1;
1971                 printk(KERN_INFO "%s machine detected. "
1972                        "Enabling interrupts during APM calls.\n", d->ident);
1973         }
1974         return 0;
1975 }
1976 
1977 /* Some APM bioses corrupt memory or just plain do not work */
1978 static int __init apm_is_horked(const struct dmi_system_id *d)
1979 {
1980         if (apm_info.disabled == 0) {
1981                 apm_info.disabled = 1;
1982                 printk(KERN_INFO "%s machine detected. "
1983                        "Disabling APM.\n", d->ident);
1984         }
1985         return 0;
1986 }
1987 
1988 static int __init apm_is_horked_d850md(const struct dmi_system_id *d)
1989 {
1990         if (apm_info.disabled == 0) {
1991                 apm_info.disabled = 1;
1992                 printk(KERN_INFO "%s machine detected. "
1993                        "Disabling APM.\n", d->ident);
1994                 printk(KERN_INFO "This bug is fixed in bios P15 which is available for\n");
1995                 printk(KERN_INFO "download from support.intel.com\n");
1996         }
1997         return 0;
1998 }
1999 
2000 /* Some APM bioses hang on APM idle calls */
2001 static int __init apm_likes_to_melt(const struct dmi_system_id *d)
2002 {
2003         if (apm_info.forbid_idle == 0) {
2004                 apm_info.forbid_idle = 1;
2005                 printk(KERN_INFO "%s machine detected. "
2006                        "Disabling APM idle calls.\n", d->ident);
2007         }
2008         return 0;
2009 }
2010 
2011 /*
2012  *  Check for clue free BIOS implementations who use
2013  *  the following QA technique
2014  *
2015  *      [ Write BIOS Code ]<------
2016  *               |                ^
2017  *      < Does it Compile >----N--
2018  *               |Y               ^
2019  *      < Does it Boot Win98 >-N--
2020  *               |Y
2021  *           [Ship It]
2022  *
2023  *      Phoenix A04  08/24/2000 is known bad (Dell Inspiron 5000e)
2024  *      Phoenix A07  09/29/2000 is known good (Dell Inspiron 5000)
2025  */
2026 static int __init broken_apm_power(const struct dmi_system_id *d)
2027 {
2028         apm_info.get_power_status_broken = 1;
2029         printk(KERN_WARNING "BIOS strings suggest APM bugs, "
2030                "disabling power status reporting.\n");
2031         return 0;
2032 }
2033 
2034 /*
2035  * This bios swaps the APM minute reporting bytes over (Many sony laptops
2036  * have this problem).
2037  */
2038 static int __init swab_apm_power_in_minutes(const struct dmi_system_id *d)
2039 {
2040         apm_info.get_power_status_swabinminutes = 1;
2041         printk(KERN_WARNING "BIOS strings suggest APM reports battery life "
2042                "in minutes and wrong byte order.\n");
2043         return 0;
2044 }
2045 
2046 static const struct dmi_system_id apm_dmi_table[] __initconst = {
2047         {
2048                 print_if_true,
2049                 KERN_WARNING "IBM T23 - BIOS 1.03b+ and controller firmware 1.02+ may be needed for Linux APM.",
2050                 {       DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
2051                         DMI_MATCH(DMI_BIOS_VERSION, "1AET38WW (1.01b)"), },
2052         },
2053         {       /* Handle problems with APM on the C600 */
2054                 broken_ps2_resume, "Dell Latitude C600",
2055                 {       DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
2056                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C600"), },
2057         },
2058         {       /* Allow interrupts during suspend on Dell Latitude laptops*/
2059                 set_apm_ints, "Dell Latitude",
2060                 {       DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2061                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C510"), }
2062         },
2063         {       /* APM crashes */
2064                 apm_is_horked, "Dell Inspiron 2500",
2065                 {       DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2066                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2067                         DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2068                         DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2069         },
2070         {       /* Allow interrupts during suspend on Dell Inspiron laptops*/
2071                 set_apm_ints, "Dell Inspiron", {
2072                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2073                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 4000"), },
2074         },
2075         {       /* Handle problems with APM on Inspiron 5000e */
2076                 broken_apm_power, "Dell Inspiron 5000e",
2077                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2078                         DMI_MATCH(DMI_BIOS_VERSION, "A04"),
2079                         DMI_MATCH(DMI_BIOS_DATE, "08/24/2000"), },
2080         },
2081         {       /* Handle problems with APM on Inspiron 2500 */
2082                 broken_apm_power, "Dell Inspiron 2500",
2083                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2084                         DMI_MATCH(DMI_BIOS_VERSION, "A12"),
2085                         DMI_MATCH(DMI_BIOS_DATE, "02/04/2002"), },
2086         },
2087         {       /* APM crashes */
2088                 apm_is_horked, "Dell Dimension 4100",
2089                 {       DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2090                         DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"),
2091                         DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2092                         DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2093         },
2094         {       /* Allow interrupts during suspend on Compaq Laptops*/
2095                 set_apm_ints, "Compaq 12XL125",
2096                 {       DMI_MATCH(DMI_SYS_VENDOR, "Compaq"),
2097                         DMI_MATCH(DMI_PRODUCT_NAME, "Compaq PC"),
2098                         DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2099                         DMI_MATCH(DMI_BIOS_VERSION, "4.06"), },
2100         },
2101         {       /* Allow interrupts during APM or the clock goes slow */
2102                 set_apm_ints, "ASUSTeK",
2103                 {       DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
2104                         DMI_MATCH(DMI_PRODUCT_NAME, "L8400K series Notebook PC"), },
2105         },
2106         {       /* APM blows on shutdown */
2107                 apm_is_horked, "ABIT KX7-333[R]",
2108                 {       DMI_MATCH(DMI_BOARD_VENDOR, "ABIT"),
2109                         DMI_MATCH(DMI_BOARD_NAME, "VT8367-8233A (KX7-333[R])"), },
2110         },
2111         {       /* APM crashes */
2112                 apm_is_horked, "Trigem Delhi3",
2113                 {       DMI_MATCH(DMI_SYS_VENDOR, "TriGem Computer, Inc"),
2114                         DMI_MATCH(DMI_PRODUCT_NAME, "Delhi3"), },
2115         },
2116         {       /* APM crashes */
2117                 apm_is_horked, "Fujitsu-Siemens",
2118                 {       DMI_MATCH(DMI_BIOS_VENDOR, "hoenix/FUJITSU SIEMENS"),
2119                         DMI_MATCH(DMI_BIOS_VERSION, "Version1.01"), },
2120         },
2121         {       /* APM crashes */
2122                 apm_is_horked_d850md, "Intel D850MD",
2123                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2124                         DMI_MATCH(DMI_BIOS_VERSION, "MV85010A.86A.0016.P07.0201251536"), },
2125         },
2126         {       /* APM crashes */
2127                 apm_is_horked, "Intel D810EMO",
2128                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2129                         DMI_MATCH(DMI_BIOS_VERSION, "MO81010A.86A.0008.P04.0004170800"), },
2130         },
2131         {       /* APM crashes */
2132                 apm_is_horked, "Dell XPS-Z",
2133                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2134                         DMI_MATCH(DMI_BIOS_VERSION, "A11"),
2135                         DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"), },
2136         },
2137         {       /* APM crashes */
2138                 apm_is_horked, "Sharp PC-PJ/AX",
2139                 {       DMI_MATCH(DMI_SYS_VENDOR, "SHARP"),
2140                         DMI_MATCH(DMI_PRODUCT_NAME, "PC-PJ/AX"),
2141                         DMI_MATCH(DMI_BIOS_VENDOR, "SystemSoft"),
2142                         DMI_MATCH(DMI_BIOS_VERSION, "Version R2.08"), },
2143         },
2144         {       /* APM crashes */
2145                 apm_is_horked, "Dell Inspiron 2500",
2146                 {       DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2147                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2148                         DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2149                         DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2150         },
2151         {       /* APM idle hangs */
2152                 apm_likes_to_melt, "Jabil AMD",
2153                 {       DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2154                         DMI_MATCH(DMI_BIOS_VERSION, "0AASNP06"), },
2155         },
2156         {       /* APM idle hangs */
2157                 apm_likes_to_melt, "AMI Bios",
2158                 {       DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2159                         DMI_MATCH(DMI_BIOS_VERSION, "0AASNP05"), },
2160         },
2161         {       /* Handle problems with APM on Sony Vaio PCG-N505X(DE) */
2162                 swab_apm_power_in_minutes, "Sony VAIO",
2163                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2164                         DMI_MATCH(DMI_BIOS_VERSION, "R0206H"),
2165                         DMI_MATCH(DMI_BIOS_DATE, "08/23/99"), },
2166         },
2167         {       /* Handle problems with APM on Sony Vaio PCG-N505VX */
2168                 swab_apm_power_in_minutes, "Sony VAIO",
2169                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2170                         DMI_MATCH(DMI_BIOS_VERSION, "W2K06H0"),
2171                         DMI_MATCH(DMI_BIOS_DATE, "02/03/00"), },
2172         },
2173         {       /* Handle problems with APM on Sony Vaio PCG-XG29 */
2174                 swab_apm_power_in_minutes, "Sony VAIO",
2175                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2176                         DMI_MATCH(DMI_BIOS_VERSION, "R0117A0"),
2177                         DMI_MATCH(DMI_BIOS_DATE, "04/25/00"), },
2178         },
2179         {       /* Handle problems with APM on Sony Vaio PCG-Z600NE */
2180                 swab_apm_power_in_minutes, "Sony VAIO",
2181                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2182                         DMI_MATCH(DMI_BIOS_VERSION, "R0121Z1"),
2183                         DMI_MATCH(DMI_BIOS_DATE, "05/11/00"), },
2184         },
2185         {       /* Handle problems with APM on Sony Vaio PCG-Z600NE */
2186                 swab_apm_power_in_minutes, "Sony VAIO",
2187                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2188                         DMI_MATCH(DMI_BIOS_VERSION, "WME01Z1"),
2189                         DMI_MATCH(DMI_BIOS_DATE, "08/11/00"), },
2190         },
2191         {       /* Handle problems with APM on Sony Vaio PCG-Z600LEK(DE) */
2192                 swab_apm_power_in_minutes, "Sony VAIO",
2193                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2194                         DMI_MATCH(DMI_BIOS_VERSION, "R0206Z3"),
2195                         DMI_MATCH(DMI_BIOS_DATE, "12/25/00"), },
2196         },
2197         {       /* Handle problems with APM on Sony Vaio PCG-Z505LS */
2198                 swab_apm_power_in_minutes, "Sony VAIO",
2199                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2200                         DMI_MATCH(DMI_BIOS_VERSION, "R0203D0"),
2201                         DMI_MATCH(DMI_BIOS_DATE, "05/12/00"), },
2202         },
2203         {       /* Handle problems with APM on Sony Vaio PCG-Z505LS */
2204                 swab_apm_power_in_minutes, "Sony VAIO",
2205                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2206                         DMI_MATCH(DMI_BIOS_VERSION, "R0203Z3"),
2207                         DMI_MATCH(DMI_BIOS_DATE, "08/25/00"), },
2208         },
2209         {       /* Handle problems with APM on Sony Vaio PCG-Z505LS (with updated BIOS) */
2210                 swab_apm_power_in_minutes, "Sony VAIO",
2211                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2212                         DMI_MATCH(DMI_BIOS_VERSION, "R0209Z3"),
2213                         DMI_MATCH(DMI_BIOS_DATE, "05/12/01"), },
2214         },
2215         {       /* Handle problems with APM on Sony Vaio PCG-F104K */
2216                 swab_apm_power_in_minutes, "Sony VAIO",
2217                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2218                         DMI_MATCH(DMI_BIOS_VERSION, "R0204K2"),
2219                         DMI_MATCH(DMI_BIOS_DATE, "08/28/00"), },
2220         },
2221 
2222         {       /* Handle problems with APM on Sony Vaio PCG-C1VN/C1VE */
2223                 swab_apm_power_in_minutes, "Sony VAIO",
2224                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2225                         DMI_MATCH(DMI_BIOS_VERSION, "R0208P1"),
2226                         DMI_MATCH(DMI_BIOS_DATE, "11/09/00"), },
2227         },
2228         {       /* Handle problems with APM on Sony Vaio PCG-C1VE */
2229                 swab_apm_power_in_minutes, "Sony VAIO",
2230                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2231                         DMI_MATCH(DMI_BIOS_VERSION, "R0204P1"),
2232                         DMI_MATCH(DMI_BIOS_DATE, "09/12/00"), },
2233         },
2234         {       /* Handle problems with APM on Sony Vaio PCG-C1VE */
2235                 swab_apm_power_in_minutes, "Sony VAIO",
2236                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2237                         DMI_MATCH(DMI_BIOS_VERSION, "WXPO1Z3"),
2238                         DMI_MATCH(DMI_BIOS_DATE, "10/26/01"), },
2239         },
2240         {       /* broken PM poweroff bios */
2241                 set_realmode_power_off, "Award Software v4.60 PGMA",
2242                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Award Software International, Inc."),
2243                         DMI_MATCH(DMI_BIOS_VERSION, "4.60 PGMA"),
2244                         DMI_MATCH(DMI_BIOS_DATE, "134526184"), },
2245         },
2246 
2247         /* Generic per vendor APM settings  */
2248 
2249         {       /* Allow interrupts during suspend on IBM laptops */
2250                 set_apm_ints, "IBM",
2251                 {       DMI_MATCH(DMI_SYS_VENDOR, "IBM"), },
2252         },
2253 
2254         { }
2255 };
2256 
2257 /*
2258  * Just start the APM thread. We do NOT want to do APM BIOS
2259  * calls from anything but the APM thread, if for no other reason
2260  * than the fact that we don't trust the APM BIOS. This way,
2261  * most common APM BIOS problems that lead to protection errors
2262  * etc will have at least some level of being contained...
2263  *
2264  * In short, if something bad happens, at least we have a choice
2265  * of just killing the apm thread..
2266  */
2267 static int __init apm_init(void)
2268 {
2269         struct desc_struct *gdt;
2270         int err;
2271 
2272         dmi_check_system(apm_dmi_table);
2273 
2274         if (apm_info.bios.version == 0 || machine_is_olpc()) {
2275                 printk(KERN_INFO "apm: BIOS not found.\n");
2276                 return -ENODEV;
2277         }
2278         printk(KERN_INFO
2279                "apm: BIOS version %d.%d Flags 0x%02x (Driver version %s)\n",
2280                ((apm_info.bios.version >> 8) & 0xff),
2281                (apm_info.bios.version & 0xff),
2282                apm_info.bios.flags,
2283                driver_version);
2284         if ((apm_info.bios.flags & APM_32_BIT_SUPPORT) == 0) {
2285                 printk(KERN_INFO "apm: no 32 bit BIOS support\n");
2286                 return -ENODEV;
2287         }
2288 
2289         if (allow_ints)
2290                 apm_info.allow_ints = 1;
2291         if (broken_psr)
2292                 apm_info.get_power_status_broken = 1;
2293         if (realmode_power_off)
2294                 apm_info.realmode_power_off = 1;
2295         /* User can override, but default is to trust DMI */
2296         if (apm_disabled != -1)
2297                 apm_info.disabled = apm_disabled;
2298 
2299         /*
2300          * Fix for the Compaq Contura 3/25c which reports BIOS version 0.1
2301          * but is reportedly a 1.0 BIOS.
2302          */
2303         if (apm_info.bios.version == 0x001)
2304                 apm_info.bios.version = 0x100;
2305 
2306         /* BIOS < 1.2 doesn't set cseg_16_len */
2307         if (apm_info.bios.version < 0x102)
2308                 apm_info.bios.cseg_16_len = 0; /* 64k */
2309 
2310         if (debug) {
2311                 printk(KERN_INFO "apm: entry %x:%x cseg16 %x dseg %x",
2312                         apm_info.bios.cseg, apm_info.bios.offset,
2313                         apm_info.bios.cseg_16, apm_info.bios.dseg);
2314                 if (apm_info.bios.version > 0x100)
2315                         printk(" cseg len %x, dseg len %x",
2316                                 apm_info.bios.cseg_len,
2317                                 apm_info.bios.dseg_len);
2318                 if (apm_info.bios.version > 0x101)
2319                         printk(" cseg16 len %x", apm_info.bios.cseg_16_len);
2320                 printk("\n");
2321         }
2322 
2323         if (apm_info.disabled) {
2324                 pr_notice("disabled on user request.\n");
2325                 return -ENODEV;
2326         }
2327         if ((num_online_cpus() > 1) && !power_off && !smp) {
2328                 pr_notice("disabled - APM is not SMP safe.\n");
2329                 apm_info.disabled = 1;
2330                 return -ENODEV;
2331         }
2332         if (!acpi_disabled) {
2333                 pr_notice("overridden by ACPI.\n");
2334                 apm_info.disabled = 1;
2335                 return -ENODEV;
2336         }
2337 
2338         /*
2339          * Set up the long jump entry point to the APM BIOS, which is called
2340          * from inline assembly.
2341          */
2342         apm_bios_entry.offset = apm_info.bios.offset;
2343         apm_bios_entry.segment = APM_CS;
2344 
2345         /*
2346          * The APM 1.1 BIOS is supposed to provide limit information that it
2347          * recognizes.  Many machines do this correctly, but many others do
2348          * not restrict themselves to their claimed limit.  When this happens,
2349          * they will cause a segmentation violation in the kernel at boot time.
2350          * Most BIOS's, however, will respect a 64k limit, so we use that.
2351          *
2352          * Note we only set APM segments on CPU zero, since we pin the APM
2353          * code to that CPU.
2354          */
2355         gdt = get_cpu_gdt_rw(0);
2356         set_desc_base(&gdt[APM_CS >> 3],
2357                  (unsigned long)__va((unsigned long)apm_info.bios.cseg << 4));
2358         set_desc_base(&gdt[APM_CS_16 >> 3],
2359                  (unsigned long)__va((unsigned long)apm_info.bios.cseg_16 << 4));
2360         set_desc_base(&gdt[APM_DS >> 3],
2361                  (unsigned long)__va((unsigned long)apm_info.bios.dseg << 4));
2362 
2363         proc_create("apm", 0, NULL, &apm_file_ops);
2364 
2365         kapmd_task = kthread_create(apm, NULL, "kapmd");
2366         if (IS_ERR(kapmd_task)) {
2367                 pr_err("disabled - Unable to start kernel thread\n");
2368                 err = PTR_ERR(kapmd_task);
2369                 kapmd_task = NULL;
2370                 remove_proc_entry("apm", NULL);
2371                 return err;
2372         }
2373         wake_up_process(kapmd_task);
2374 
2375         if (num_online_cpus() > 1 && !smp) {
2376                 printk(KERN_NOTICE
2377                        "apm: disabled - APM is not SMP safe (power off active).\n");
2378                 return 0;
2379         }
2380 
2381         /*
2382          * Note we don't actually care if the misc_device cannot be registered.
2383          * this driver can do its job without it, even if userspace can't
2384          * control it.  just log the error
2385          */
2386         if (misc_register(&apm_device))
2387                 printk(KERN_WARNING "apm: Could not register misc device.\n");
2388 
2389         if (HZ != 100)
2390                 idle_period = (idle_period * HZ) / 100;
2391         if (idle_threshold < 100) {
2392                 cpuidle_poll_state_init(&apm_idle_driver);
2393                 if (!cpuidle_register_driver(&apm_idle_driver))
2394                         if (cpuidle_register_device(&apm_cpuidle_device))
2395                                 cpuidle_unregister_driver(&apm_idle_driver);
2396         }
2397 
2398         return 0;
2399 }
2400 
2401 static void __exit apm_exit(void)
2402 {
2403         int error;
2404 
2405         cpuidle_unregister_device(&apm_cpuidle_device);
2406         cpuidle_unregister_driver(&apm_idle_driver);
2407 
2408         if (((apm_info.bios.flags & APM_BIOS_DISENGAGED) == 0)
2409             && (apm_info.connection_version > 0x0100)) {
2410                 error = apm_engage_power_management(APM_DEVICE_ALL, 0);
2411                 if (error)
2412                         apm_error("disengage power management", error);
2413         }
2414         misc_deregister(&apm_device);
2415         remove_proc_entry("apm", NULL);
2416         if (power_off)
2417                 pm_power_off = NULL;
2418         if (kapmd_task) {
2419                 kthread_stop(kapmd_task);
2420                 kapmd_task = NULL;
2421         }
2422 }
2423 
2424 module_init(apm_init);
2425 module_exit(apm_exit);
2426 
2427 MODULE_AUTHOR("Stephen Rothwell");
2428 MODULE_DESCRIPTION("Advanced Power Management");
2429 MODULE_LICENSE("GPL");
2430 module_param(debug, bool, 0644);
2431 MODULE_PARM_DESC(debug, "Enable debug mode");
2432 module_param(power_off, bool, 0444);
2433 MODULE_PARM_DESC(power_off, "Enable power off");
2434 module_param(bounce_interval, int, 0444);
2435 MODULE_PARM_DESC(bounce_interval,
2436                 "Set the number of ticks to ignore suspend bounces");
2437 module_param(allow_ints, bool, 0444);
2438 MODULE_PARM_DESC(allow_ints, "Allow interrupts during BIOS calls");
2439 module_param(broken_psr, bool, 0444);
2440 MODULE_PARM_DESC(broken_psr, "BIOS has a broken GetPowerStatus call");
2441 module_param(realmode_power_off, bool, 0444);
2442 MODULE_PARM_DESC(realmode_power_off,
2443                 "Switch to real mode before powering off");
2444 module_param(idle_threshold, int, 0444);
2445 MODULE_PARM_DESC(idle_threshold,
2446         "System idle percentage above which to make APM BIOS idle calls");
2447 module_param(idle_period, int, 0444);
2448 MODULE_PARM_DESC(idle_period,
2449         "Period (in sec/100) over which to caculate the idle percentage");
2450 module_param(smp, bool, 0444);
2451 MODULE_PARM_DESC(smp,
2452         "Set this to enable APM use on an SMP platform. Use with caution on older systems");
2453 MODULE_ALIAS_MISCDEV(APM_MINOR_DEV);
2454 

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