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Linux/arch/x86/kernel/apm_32.c

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

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