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TOMOYO Linux Cross Reference
Linux/arch/x86/kernel/apm_32.c

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  1 /* -*- linux-c -*-
  2  * APM BIOS driver for Linux
  3  * Copyright 1994-2001 Stephen Rothwell (sfr@canb.auug.org.au)
  4  *
  5  * Initial development of this driver was funded by NEC Australia P/L
  6  *      and NEC Corporation
  7  *
  8  * This program is free software; you can redistribute it and/or modify it
  9  * under the terms of the GNU General Public License as published by the
 10  * Free Software Foundation; either version 2, or (at your option) any
 11  * later version.
 12  *
 13  * This program is distributed in the hope that it will be useful, but
 14  * WITHOUT ANY WARRANTY; without even the implied warranty of
 15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 16  * General Public License for more details.
 17  *
 18  * October 1995, Rik Faith (faith@cs.unc.edu):
 19  *    Minor enhancements and updates (to the patch set) for 1.3.x
 20  *    Documentation
 21  * January 1996, Rik Faith (faith@cs.unc.edu):
 22  *    Make /proc/apm easy to format (bump driver version)
 23  * March 1996, Rik Faith (faith@cs.unc.edu):
 24  *    Prohibit APM BIOS calls unless apm_enabled.
 25  *    (Thanks to Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>)
 26  * April 1996, Stephen Rothwell (sfr@canb.auug.org.au)
 27  *    Version 1.0 and 1.1
 28  * May 1996, Version 1.2
 29  * Feb 1998, Version 1.3
 30  * Feb 1998, Version 1.4
 31  * Aug 1998, Version 1.5
 32  * Sep 1998, Version 1.6
 33  * Nov 1998, Version 1.7
 34  * Jan 1999, Version 1.8
 35  * Jan 1999, Version 1.9
 36  * Oct 1999, Version 1.10
 37  * Nov 1999, Version 1.11
 38  * Jan 2000, Version 1.12
 39  * Feb 2000, Version 1.13
 40  * Nov 2000, Version 1.14
 41  * Oct 2001, Version 1.15
 42  * Jan 2002, Version 1.16
 43  * Oct 2002, Version 1.16ac
 44  *
 45  * History:
 46  *    0.6b: first version in official kernel, Linux 1.3.46
 47  *    0.7: changed /proc/apm format, Linux 1.3.58
 48  *    0.8: fixed gcc 2.7.[12] compilation problems, Linux 1.3.59
 49  *    0.9: only call bios if bios is present, Linux 1.3.72
 50  *    1.0: use fixed device number, consolidate /proc/apm into this file,
 51  *         Linux 1.3.85
 52  *    1.1: support user-space standby and suspend, power off after system
 53  *         halted, Linux 1.3.98
 54  *    1.2: When resetting RTC after resume, take care so that the time
 55  *         is only incorrect by 30-60mS (vs. 1S previously) (Gabor J. Toth
 56  *         <jtoth@princeton.edu>); improve interaction between
 57  *         screen-blanking and gpm (Stephen Rothwell); Linux 1.99.4
 58  *    1.2a:Simple change to stop mysterious bug reports with SMP also added
 59  *         levels to the printk calls. APM is not defined for SMP machines.
 60  *         The new replacement for it is, but Linux doesn't yet support this.
 61  *         Alan Cox Linux 2.1.55
 62  *    1.3: Set up a valid data descriptor 0x40 for buggy BIOS's
 63  *    1.4: Upgraded to support APM 1.2. Integrated ThinkPad suspend patch by
 64  *         Dean Gaudet <dgaudet@arctic.org>.
 65  *         C. Scott Ananian <cananian@alumni.princeton.edu> Linux 2.1.87
 66  *    1.5: Fix segment register reloading (in case of bad segments saved
 67  *         across BIOS call).
 68  *         Stephen Rothwell
 69  *    1.6: Cope with compiler/assembler differences.
 70  *         Only try to turn off the first display device.
 71  *         Fix OOPS at power off with no APM BIOS by Jan Echternach
 72  *                   <echter@informatik.uni-rostock.de>
 73  *         Stephen Rothwell
 74  *    1.7: Modify driver's cached copy of the disabled/disengaged flags
 75  *         to reflect current state of APM BIOS.
 76  *         Chris Rankin <rankinc@bellsouth.net>
 77  *         Reset interrupt 0 timer to 100Hz after suspend
 78  *         Chad Miller <cmiller@surfsouth.com>
 79  *         Add CONFIG_APM_IGNORE_SUSPEND_BOUNCE
 80  *         Richard Gooch <rgooch@atnf.csiro.au>
 81  *         Allow boot time disabling of APM
 82  *         Make boot messages far less verbose by default
 83  *         Make asm safer
 84  *         Stephen Rothwell
 85  *    1.8: Add CONFIG_APM_RTC_IS_GMT
 86  *         Richard Gooch <rgooch@atnf.csiro.au>
 87  *         change APM_NOINTS to CONFIG_APM_ALLOW_INTS
 88  *         remove dependency on CONFIG_PROC_FS
 89  *         Stephen Rothwell
 90  *    1.9: Fix small typo.  <laslo@wodip.opole.pl>
 91  *         Try to cope with BIOS's that need to have all display
 92  *         devices blanked and not just the first one.
 93  *         Ross Paterson <ross@soi.city.ac.uk>
 94  *         Fix segment limit setting it has always been wrong as
 95  *         the segments needed to have byte granularity.
 96  *         Mark a few things __init.
 97  *         Add hack to allow power off of SMP systems by popular request.
 98  *         Use CONFIG_SMP instead of __SMP__
 99  *         Ignore BOUNCES for three seconds.
100  *         Stephen Rothwell
101  *   1.10: Fix for Thinkpad return code.
102  *         Merge 2.2 and 2.3 drivers.
103  *         Remove APM dependencies in arch/i386/kernel/process.c
104  *         Remove APM dependencies in drivers/char/sysrq.c
105  *         Reset time across standby.
106  *         Allow more inititialisation on SMP.
107  *         Remove CONFIG_APM_POWER_OFF and make it boot time
108  *         configurable (default on).
109  *         Make debug only a boot time parameter (remove APM_DEBUG).
110  *         Try to blank all devices on any error.
111  *   1.11: Remove APM dependencies in drivers/char/console.c
112  *         Check nr_running to detect if we are idle (from
113  *         Borislav Deianov <borislav@lix.polytechnique.fr>)
114  *         Fix for bioses that don't zero the top part of the
115  *         entrypoint offset (Mario Sitta <sitta@al.unipmn.it>)
116  *         (reported by Panos Katsaloulis <teras@writeme.com>).
117  *         Real mode power off patch (Walter Hofmann
118  *         <Walter.Hofmann@physik.stud.uni-erlangen.de>).
119  *   1.12: Remove CONFIG_SMP as the compiler will optimize
120  *         the code away anyway (smp_num_cpus == 1 in UP)
121  *         noted by Artur Skawina <skawina@geocities.com>.
122  *         Make power off under SMP work again.
123  *         Fix thinko with initial engaging of BIOS.
124  *         Make sure power off only happens on CPU 0
125  *         (Paul "Rusty" Russell <rusty@rustcorp.com.au>).
126  *         Do error notification to user mode if BIOS calls fail.
127  *         Move entrypoint offset fix to ...boot/setup.S
128  *         where it belongs (Cosmos <gis88564@cis.nctu.edu.tw>).
129  *         Remove smp-power-off. SMP users must now specify
130  *         "apm=power-off" on the kernel command line. Suggested
131  *         by Jim Avera <jima@hal.com>, modified by Alan Cox
132  *         <alan@lxorguk.ukuu.org.uk>.
133  *         Register the /proc/apm entry even on SMP so that
134  *         scripts that check for it before doing power off
135  *         work (Jim Avera <jima@hal.com>).
136  *   1.13: Changes for new pm_ interfaces (Andy Henroid
137  *         <andy_henroid@yahoo.com>).
138  *         Modularize the code.
139  *         Fix the Thinkpad (again) :-( (CONFIG_APM_IGNORE_MULTIPLE_SUSPENDS
140  *         is now the way life works).
141  *         Fix thinko in suspend() (wrong return).
142  *         Notify drivers on critical suspend.
143  *         Make kapmd absorb more idle time (Pavel Machek <pavel@ucw.cz>
144  *         modified by sfr).
145  *         Disable interrupts while we are suspended (Andy Henroid
146  *         <andy_henroid@yahoo.com> fixed by sfr).
147  *         Make power off work on SMP again (Tony Hoyle
148  *         <tmh@magenta-logic.com> and <zlatko@iskon.hr>) modified by sfr.
149  *         Remove CONFIG_APM_SUSPEND_BOUNCE.  The bounce ignore
150  *         interval is now configurable.
151  *   1.14: Make connection version persist across module unload/load.
152  *         Enable and engage power management earlier.
153  *         Disengage power management on module unload.
154  *         Changed to use the sysrq-register hack for registering the
155  *         power off function called by magic sysrq based upon discussions
156  *         in irc://irc.openprojects.net/#kernelnewbies
157  *         (Crutcher Dunnavant <crutcher+kernel@datastacks.com>).
158  *         Make CONFIG_APM_REAL_MODE_POWER_OFF run time configurable.
159  *         (Arjan van de Ven <arjanv@redhat.com>) modified by sfr.
160  *         Work around byte swap bug in one of the Vaio's BIOS's
161  *         (Marc Boucher <marc@mbsi.ca>).
162  *         Exposed the disable flag to dmi so that we can handle known
163  *         broken APM (Alan Cox <alan@lxorguk.ukuu.org.uk>).
164  *   1.14ac: If the BIOS says "I slowed the CPU down" then don't spin
165  *         calling it - instead idle. (Alan Cox <alan@lxorguk.ukuu.org.uk>)
166  *         If an APM idle fails log it and idle sensibly
167  *   1.15: Don't queue events to clients who open the device O_WRONLY.
168  *         Don't expect replies from clients who open the device O_RDONLY.
169  *         (Idea from Thomas Hood)
170  *         Minor waitqueue cleanups. (John Fremlin <chief@bandits.org>)
171  *   1.16: Fix idle calling. (Andreas Steinmetz <ast@domdv.de> et al.)
172  *         Notify listeners of standby or suspend events before notifying
173  *         drivers. Return EBUSY to ioctl() if suspend is rejected.
174  *         (Russell King <rmk@arm.linux.org.uk> and Thomas Hood)
175  *         Ignore first resume after we generate our own resume event
176  *         after a suspend (Thomas Hood)
177  *         Daemonize now gets rid of our controlling terminal (sfr).
178  *         CONFIG_APM_CPU_IDLE now just affects the default value of
179  *         idle_threshold (sfr).
180  *         Change name of kernel apm daemon (as it no longer idles) (sfr).
181  *   1.16ac: Fix up SMP support somewhat. You can now force SMP on and we
182  *         make _all_ APM calls on the CPU#0. Fix unsafe sign bug.
183  *         TODO: determine if its "boot CPU" or "CPU0" we want to lock to.
184  *
185  * APM 1.1 Reference:
186  *
187  *   Intel Corporation, Microsoft Corporation. Advanced Power Management
188  *   (APM) BIOS Interface Specification, Revision 1.1, September 1993.
189  *   Intel Order Number 241704-001.  Microsoft Part Number 781-110-X01.
190  *
191  * [This document is available free from Intel by calling 800.628.8686 (fax
192  * 916.356.6100) or 800.548.4725; or from
193  * http://www.microsoft.com/whdc/archive/amp_12.mspx  It is also
194  * available from Microsoft by calling 206.882.8080.]
195  *
196  * APM 1.2 Reference:
197  *   Intel Corporation, Microsoft Corporation. Advanced Power Management
198  *   (APM) BIOS Interface Specification, Revision 1.2, February 1996.
199  *
200  * [This document is available from Microsoft at:
201  *    http://www.microsoft.com/whdc/archive/amp_12.mspx]
202  */
203 
204 #define pr_fmt(fmt) "apm: " fmt
205 
206 #include <linux/module.h>
207 
208 #include <linux/poll.h>
209 #include <linux/types.h>
210 #include <linux/stddef.h>
211 #include <linux/timer.h>
212 #include <linux/fcntl.h>
213 #include <linux/slab.h>
214 #include <linux/stat.h>
215 #include <linux/proc_fs.h>
216 #include <linux/seq_file.h>
217 #include <linux/miscdevice.h>
218 #include <linux/apm_bios.h>
219 #include <linux/init.h>
220 #include <linux/time.h>
221 #include <linux/sched/signal.h>
222 #include <linux/sched/cputime.h>
223 #include <linux/pm.h>
224 #include <linux/capability.h>
225 #include <linux/device.h>
226 #include <linux/kernel.h>
227 #include <linux/freezer.h>
228 #include <linux/smp.h>
229 #include <linux/dmi.h>
230 #include <linux/suspend.h>
231 #include <linux/kthread.h>
232 #include <linux/jiffies.h>
233 #include <linux/acpi.h>
234 #include <linux/syscore_ops.h>
235 #include <linux/i8253.h>
236 #include <linux/cpuidle.h>
237 
238 #include <linux/uaccess.h>
239 #include <asm/desc.h>
240 #include <asm/olpc.h>
241 #include <asm/paravirt.h>
242 #include <asm/reboot.h>
243 #include <asm/nospec-branch.h>
244 
245 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
246 extern int (*console_blank_hook)(int);
247 #endif
248 
249 /*
250  * The apm_bios device is one of the misc char devices.
251  * This is its minor number.
252  */
253 #define APM_MINOR_DEV   134
254 
255 /*
256  * Various options can be changed at boot time as follows:
257  * (We allow underscores for compatibility with the modules code)
258  *      apm=on/off                      enable/disable APM
259  *          [no-]allow[-_]ints          allow interrupts during BIOS calls
260  *          [no-]broken[-_]psr          BIOS has a broken GetPowerStatus call
261  *          [no-]realmode[-_]power[-_]off       switch to real mode before
262  *                                              powering off
263  *          [no-]debug                  log some debugging messages
264  *          [no-]power[-_]off           power off on shutdown
265  *          [no-]smp                    Use apm even on an SMP box
266  *          bounce[-_]interval=<n>      number of ticks to ignore suspend
267  *                                      bounces
268  *          idle[-_]threshold=<n>       System idle percentage above which to
269  *                                      make APM BIOS idle calls. Set it to
270  *                                      100 to disable.
271  *          idle[-_]period=<n>          Period (in 1/100s of a second) over
272  *                                      which the idle percentage is
273  *                                      calculated.
274  */
275 
276 /* KNOWN PROBLEM MACHINES:
277  *
278  * U: TI 4000M TravelMate: BIOS is *NOT* APM compliant
279  *                         [Confirmed by TI representative]
280  * ?: ACER 486DX4/75: uses dseg 0040, in violation of APM specification
281  *                    [Confirmed by BIOS disassembly]
282  *                    [This may work now ...]
283  * P: Toshiba 1950S: battery life information only gets updated after resume
284  * P: Midwest Micro Soundbook Elite DX2/66 monochrome: screen blanking
285  *      broken in BIOS [Reported by Garst R. Reese <reese@isn.net>]
286  * ?: AcerNote-950: oops on reading /proc/apm - workaround is a WIP
287  *      Neale Banks <neale@lowendale.com.au> December 2000
288  *
289  * Legend: U = unusable with APM patches
290  *         P = partially usable with APM patches
291  */
292 
293 /*
294  * Define as 1 to make the driver always call the APM BIOS busy
295  * routine even if the clock was not reported as slowed by the
296  * idle routine.  Otherwise, define as 0.
297  */
298 #define ALWAYS_CALL_BUSY   1
299 
300 /*
301  * Define to make the APM BIOS calls zero all data segment registers (so
302  * that an incorrect BIOS implementation will cause a kernel panic if it
303  * tries to write to arbitrary memory).
304  */
305 #define APM_ZERO_SEGS
306 
307 #include <asm/apm.h>
308 
309 /*
310  * Define to re-initialize the interrupt 0 timer to 100 Hz after a suspend.
311  * This patched by Chad Miller <cmiller@surfsouth.com>, original code by
312  * David Chen <chen@ctpa04.mit.edu>
313  */
314 #undef INIT_TIMER_AFTER_SUSPEND
315 
316 #ifdef INIT_TIMER_AFTER_SUSPEND
317 #include <linux/timex.h>
318 #include <asm/io.h>
319 #include <linux/delay.h>
320 #endif
321 
322 /*
323  * Need to poll the APM BIOS every second
324  */
325 #define APM_CHECK_TIMEOUT       (HZ)
326 
327 /*
328  * Ignore suspend events for this amount of time after a resume
329  */
330 #define DEFAULT_BOUNCE_INTERVAL (3 * HZ)
331 
332 /*
333  * Maximum number of events stored
334  */
335 #define APM_MAX_EVENTS          20
336 
337 /*
338  * The per-file APM data
339  */
340 struct apm_user {
341         int             magic;
342         struct apm_user *next;
343         unsigned int    suser: 1;
344         unsigned int    writer: 1;
345         unsigned int    reader: 1;
346         unsigned int    suspend_wait: 1;
347         int             suspend_result;
348         int             suspends_pending;
349         int             standbys_pending;
350         int             suspends_read;
351         int             standbys_read;
352         int             event_head;
353         int             event_tail;
354         apm_event_t     events[APM_MAX_EVENTS];
355 };
356 
357 /*
358  * The magic number in apm_user
359  */
360 #define APM_BIOS_MAGIC          0x4101
361 
362 /*
363  * idle percentage above which bios idle calls are done
364  */
365 #ifdef CONFIG_APM_CPU_IDLE
366 #define DEFAULT_IDLE_THRESHOLD  95
367 #else
368 #define DEFAULT_IDLE_THRESHOLD  100
369 #endif
370 #define DEFAULT_IDLE_PERIOD     (100 / 3)
371 
372 static int apm_cpu_idle(struct cpuidle_device *dev,
373                         struct cpuidle_driver *drv, int index);
374 
375 static struct cpuidle_driver apm_idle_driver = {
376         .name = "apm_idle",
377         .owner = THIS_MODULE,
378         .states = {
379                 { /* entry 0 is for polling */ },
380                 { /* entry 1 is for APM idle */
381                         .name = "APM",
382                         .desc = "APM idle",
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_rw(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_rw(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 u64 last_stime; /* = 0 */
915         u64 stime, utime;
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, &utime, &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 = nsecs_to_jiffies(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                 if (!call.err)
1053                         return APM_NO_ERROR;
1054                 return call.err;
1055         }
1056         *status = call.ebx;
1057         *bat = call.ecx;
1058         if (apm_info.get_power_status_swabinminutes) {
1059                 *life = swab16((u16)call.edx);
1060                 *life |= 0x8000;
1061         } else
1062                 *life = call.edx;
1063         return APM_SUCCESS;
1064 }
1065 
1066 #if 0
1067 static int apm_get_battery_status(u_short which, u_short *status,
1068                                   u_short *bat, u_short *life, u_short *nbat)
1069 {
1070         u32 eax;
1071         u32 ebx;
1072         u32 ecx;
1073         u32 edx;
1074         u32 esi;
1075 
1076         if (apm_info.connection_version < 0x0102) {
1077                 /* pretend we only have one battery. */
1078                 if (which != 1)
1079                         return APM_BAD_DEVICE;
1080                 *nbat = 1;
1081                 return apm_get_power_status(status, bat, life);
1082         }
1083 
1084         if (apm_bios_call(APM_FUNC_GET_STATUS, (0x8000 | (which)), 0, &eax,
1085                           &ebx, &ecx, &edx, &esi))
1086                 return (eax >> 8) & 0xff;
1087         *status = ebx;
1088         *bat = ecx;
1089         *life = edx;
1090         *nbat = esi;
1091         return APM_SUCCESS;
1092 }
1093 #endif
1094 
1095 /**
1096  *      apm_engage_power_management     -       enable PM on a device
1097  *      @device: identity of device
1098  *      @enable: on/off
1099  *
1100  *      Activate or deactivate power management on either a specific device
1101  *      or the entire system (%APM_DEVICE_ALL).
1102  */
1103 
1104 static int apm_engage_power_management(u_short device, int enable)
1105 {
1106         u32 eax;
1107         int err;
1108 
1109         if ((enable == 0) && (device == APM_DEVICE_ALL)
1110             && (apm_info.bios.flags & APM_BIOS_DISABLED))
1111                 return APM_DISABLED;
1112         if (apm_bios_call_simple(APM_FUNC_ENGAGE_PM, device, enable,
1113                                  &eax, &err))
1114                 return err;
1115         if (device == APM_DEVICE_ALL) {
1116                 if (enable)
1117                         apm_info.bios.flags &= ~APM_BIOS_DISENGAGED;
1118                 else
1119                         apm_info.bios.flags |= APM_BIOS_DISENGAGED;
1120         }
1121         return APM_SUCCESS;
1122 }
1123 
1124 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1125 
1126 /**
1127  *      apm_console_blank       -       blank the display
1128  *      @blank: on/off
1129  *
1130  *      Attempt to blank the console, firstly by blanking just video device
1131  *      zero, and if that fails (some BIOSes don't support it) then it blanks
1132  *      all video devices. Typically the BIOS will do laptop backlight and
1133  *      monitor powerdown for us.
1134  */
1135 
1136 static int apm_console_blank(int blank)
1137 {
1138         int error = APM_NOT_ENGAGED; /* silence gcc */
1139         int i;
1140         u_short state;
1141         static const u_short dev[3] = { 0x100, 0x1FF, 0x101 };
1142 
1143         state = blank ? APM_STATE_STANDBY : APM_STATE_READY;
1144 
1145         for (i = 0; i < ARRAY_SIZE(dev); i++) {
1146                 error = set_power_state(dev[i], state);
1147 
1148                 if ((error == APM_SUCCESS) || (error == APM_NO_ERROR))
1149                         return 1;
1150 
1151                 if (error == APM_NOT_ENGAGED)
1152                         break;
1153         }
1154 
1155         if (error == APM_NOT_ENGAGED) {
1156                 static int tried;
1157                 int eng_error;
1158                 if (tried++ == 0) {
1159                         eng_error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1160                         if (eng_error) {
1161                                 apm_error("set display", error);
1162                                 apm_error("engage interface", eng_error);
1163                                 return 0;
1164                         } else
1165                                 return apm_console_blank(blank);
1166                 }
1167         }
1168         apm_error("set display", error);
1169         return 0;
1170 }
1171 #endif
1172 
1173 static int queue_empty(struct apm_user *as)
1174 {
1175         return as->event_head == as->event_tail;
1176 }
1177 
1178 static apm_event_t get_queued_event(struct apm_user *as)
1179 {
1180         if (++as->event_tail >= APM_MAX_EVENTS)
1181                 as->event_tail = 0;
1182         return as->events[as->event_tail];
1183 }
1184 
1185 static void queue_event(apm_event_t event, struct apm_user *sender)
1186 {
1187         struct apm_user *as;
1188 
1189         spin_lock(&user_list_lock);
1190         if (user_list == NULL)
1191                 goto out;
1192         for (as = user_list; as != NULL; as = as->next) {
1193                 if ((as == sender) || (!as->reader))
1194                         continue;
1195                 if (++as->event_head >= APM_MAX_EVENTS)
1196                         as->event_head = 0;
1197 
1198                 if (as->event_head == as->event_tail) {
1199                         static int notified;
1200 
1201                         if (notified++ == 0)
1202                                 pr_err("an event queue overflowed\n");
1203                         if (++as->event_tail >= APM_MAX_EVENTS)
1204                                 as->event_tail = 0;
1205                 }
1206                 as->events[as->event_head] = event;
1207                 if (!as->suser || !as->writer)
1208                         continue;
1209                 switch (event) {
1210                 case APM_SYS_SUSPEND:
1211                 case APM_USER_SUSPEND:
1212                         as->suspends_pending++;
1213                         suspends_pending++;
1214                         break;
1215 
1216                 case APM_SYS_STANDBY:
1217                 case APM_USER_STANDBY:
1218                         as->standbys_pending++;
1219                         standbys_pending++;
1220                         break;
1221                 }
1222         }
1223         wake_up_interruptible(&apm_waitqueue);
1224 out:
1225         spin_unlock(&user_list_lock);
1226 }
1227 
1228 static void reinit_timer(void)
1229 {
1230 #ifdef INIT_TIMER_AFTER_SUSPEND
1231         unsigned long flags;
1232 
1233         raw_spin_lock_irqsave(&i8253_lock, flags);
1234         /* set the clock to HZ */
1235         outb_p(0x34, PIT_MODE);         /* binary, mode 2, LSB/MSB, ch 0 */
1236         udelay(10);
1237         outb_p(LATCH & 0xff, PIT_CH0);  /* LSB */
1238         udelay(10);
1239         outb_p(LATCH >> 8, PIT_CH0);    /* MSB */
1240         udelay(10);
1241         raw_spin_unlock_irqrestore(&i8253_lock, flags);
1242 #endif
1243 }
1244 
1245 static int suspend(int vetoable)
1246 {
1247         int err;
1248         struct apm_user *as;
1249 
1250         dpm_suspend_start(PMSG_SUSPEND);
1251         dpm_suspend_end(PMSG_SUSPEND);
1252 
1253         local_irq_disable();
1254         syscore_suspend();
1255 
1256         local_irq_enable();
1257 
1258         save_processor_state();
1259         err = set_system_power_state(APM_STATE_SUSPEND);
1260         ignore_normal_resume = 1;
1261         restore_processor_state();
1262 
1263         local_irq_disable();
1264         reinit_timer();
1265 
1266         if (err == APM_NO_ERROR)
1267                 err = APM_SUCCESS;
1268         if (err != APM_SUCCESS)
1269                 apm_error("suspend", err);
1270         err = (err == APM_SUCCESS) ? 0 : -EIO;
1271 
1272         syscore_resume();
1273         local_irq_enable();
1274 
1275         dpm_resume_start(PMSG_RESUME);
1276         dpm_resume_end(PMSG_RESUME);
1277 
1278         queue_event(APM_NORMAL_RESUME, NULL);
1279         spin_lock(&user_list_lock);
1280         for (as = user_list; as != NULL; as = as->next) {
1281                 as->suspend_wait = 0;
1282                 as->suspend_result = err;
1283         }
1284         spin_unlock(&user_list_lock);
1285         wake_up_interruptible(&apm_suspend_waitqueue);
1286         return err;
1287 }
1288 
1289 static void standby(void)
1290 {
1291         int err;
1292 
1293         dpm_suspend_end(PMSG_SUSPEND);
1294 
1295         local_irq_disable();
1296         syscore_suspend();
1297         local_irq_enable();
1298 
1299         err = set_system_power_state(APM_STATE_STANDBY);
1300         if ((err != APM_SUCCESS) && (err != APM_NO_ERROR))
1301                 apm_error("standby", err);
1302 
1303         local_irq_disable();
1304         syscore_resume();
1305         local_irq_enable();
1306 
1307         dpm_resume_start(PMSG_RESUME);
1308 }
1309 
1310 static apm_event_t get_event(void)
1311 {
1312         int error;
1313         apm_event_t event = APM_NO_EVENTS; /* silence gcc */
1314         apm_eventinfo_t info;
1315 
1316         static int notified;
1317 
1318         /* we don't use the eventinfo */
1319         error = apm_get_event(&event, &info);
1320         if (error == APM_SUCCESS)
1321                 return event;
1322 
1323         if ((error != APM_NO_EVENTS) && (notified++ == 0))
1324                 apm_error("get_event", error);
1325 
1326         return 0;
1327 }
1328 
1329 static void check_events(void)
1330 {
1331         apm_event_t event;
1332         static unsigned long last_resume;
1333         static int ignore_bounce;
1334 
1335         while ((event = get_event()) != 0) {
1336                 if (debug) {
1337                         if (event <= NR_APM_EVENT_NAME)
1338                                 printk(KERN_DEBUG "apm: received %s notify\n",
1339                                        apm_event_name[event - 1]);
1340                         else
1341                                 printk(KERN_DEBUG "apm: received unknown "
1342                                        "event 0x%02x\n", event);
1343                 }
1344                 if (ignore_bounce
1345                     && (time_after(jiffies, last_resume + bounce_interval)))
1346                         ignore_bounce = 0;
1347 
1348                 switch (event) {
1349                 case APM_SYS_STANDBY:
1350                 case APM_USER_STANDBY:
1351                         queue_event(event, NULL);
1352                         if (standbys_pending <= 0)
1353                                 standby();
1354                         break;
1355 
1356                 case APM_USER_SUSPEND:
1357 #ifdef CONFIG_APM_IGNORE_USER_SUSPEND
1358                         if (apm_info.connection_version > 0x100)
1359                                 set_system_power_state(APM_STATE_REJECT);
1360                         break;
1361 #endif
1362                 case APM_SYS_SUSPEND:
1363                         if (ignore_bounce) {
1364                                 if (apm_info.connection_version > 0x100)
1365                                         set_system_power_state(APM_STATE_REJECT);
1366                                 break;
1367                         }
1368                         /*
1369                          * If we are already processing a SUSPEND,
1370                          * then further SUSPEND events from the BIOS
1371                          * will be ignored.  We also return here to
1372                          * cope with the fact that the Thinkpads keep
1373                          * sending a SUSPEND event until something else
1374                          * happens!
1375                          */
1376                         if (ignore_sys_suspend)
1377                                 return;
1378                         ignore_sys_suspend = 1;
1379                         queue_event(event, NULL);
1380                         if (suspends_pending <= 0)
1381                                 (void) suspend(1);
1382                         break;
1383 
1384                 case APM_NORMAL_RESUME:
1385                 case APM_CRITICAL_RESUME:
1386                 case APM_STANDBY_RESUME:
1387                         ignore_sys_suspend = 0;
1388                         last_resume = jiffies;
1389                         ignore_bounce = 1;
1390                         if ((event != APM_NORMAL_RESUME)
1391                             || (ignore_normal_resume == 0)) {
1392                                 dpm_resume_end(PMSG_RESUME);
1393                                 queue_event(event, NULL);
1394                         }
1395                         ignore_normal_resume = 0;
1396                         break;
1397 
1398                 case APM_CAPABILITY_CHANGE:
1399                 case APM_LOW_BATTERY:
1400                 case APM_POWER_STATUS_CHANGE:
1401                         queue_event(event, NULL);
1402                         /* If needed, notify drivers here */
1403                         break;
1404 
1405                 case APM_UPDATE_TIME:
1406                         break;
1407 
1408                 case APM_CRITICAL_SUSPEND:
1409                         /*
1410                          * We are not allowed to reject a critical suspend.
1411                          */
1412                         (void)suspend(0);
1413                         break;
1414                 }
1415         }
1416 }
1417 
1418 static void apm_event_handler(void)
1419 {
1420         static int pending_count = 4;
1421         int err;
1422 
1423         if ((standbys_pending > 0) || (suspends_pending > 0)) {
1424                 if ((apm_info.connection_version > 0x100) &&
1425                     (pending_count-- <= 0)) {
1426                         pending_count = 4;
1427                         if (debug)
1428                                 printk(KERN_DEBUG "apm: setting state busy\n");
1429                         err = set_system_power_state(APM_STATE_BUSY);
1430                         if (err)
1431                                 apm_error("busy", err);
1432                 }
1433         } else
1434                 pending_count = 4;
1435         check_events();
1436 }
1437 
1438 /*
1439  * This is the APM thread main loop.
1440  */
1441 
1442 static void apm_mainloop(void)
1443 {
1444         DECLARE_WAITQUEUE(wait, current);
1445 
1446         add_wait_queue(&apm_waitqueue, &wait);
1447         set_current_state(TASK_INTERRUPTIBLE);
1448         for (;;) {
1449                 schedule_timeout(APM_CHECK_TIMEOUT);
1450                 if (kthread_should_stop())
1451                         break;
1452                 /*
1453                  * Ok, check all events, check for idle (and mark us sleeping
1454                  * so as not to count towards the load average)..
1455                  */
1456                 set_current_state(TASK_INTERRUPTIBLE);
1457                 apm_event_handler();
1458         }
1459         remove_wait_queue(&apm_waitqueue, &wait);
1460 }
1461 
1462 static int check_apm_user(struct apm_user *as, const char *func)
1463 {
1464         if (as == NULL || as->magic != APM_BIOS_MAGIC) {
1465                 pr_err("%s passed bad filp\n", func);
1466                 return 1;
1467         }
1468         return 0;
1469 }
1470 
1471 static ssize_t do_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
1472 {
1473         struct apm_user *as;
1474         int i;
1475         apm_event_t event;
1476 
1477         as = fp->private_data;
1478         if (check_apm_user(as, "read"))
1479                 return -EIO;
1480         if ((int)count < sizeof(apm_event_t))
1481                 return -EINVAL;
1482         if ((queue_empty(as)) && (fp->f_flags & O_NONBLOCK))
1483                 return -EAGAIN;
1484         wait_event_interruptible(apm_waitqueue, !queue_empty(as));
1485         i = count;
1486         while ((i >= sizeof(event)) && !queue_empty(as)) {
1487                 event = get_queued_event(as);
1488                 if (copy_to_user(buf, &event, sizeof(event))) {
1489                         if (i < count)
1490                                 break;
1491                         return -EFAULT;
1492                 }
1493                 switch (event) {
1494                 case APM_SYS_SUSPEND:
1495                 case APM_USER_SUSPEND:
1496                         as->suspends_read++;
1497                         break;
1498 
1499                 case APM_SYS_STANDBY:
1500                 case APM_USER_STANDBY:
1501                         as->standbys_read++;
1502                         break;
1503                 }
1504                 buf += sizeof(event);
1505                 i -= sizeof(event);
1506         }
1507         if (i < count)
1508                 return count - i;
1509         if (signal_pending(current))
1510                 return -ERESTARTSYS;
1511         return 0;
1512 }
1513 
1514 static __poll_t do_poll(struct file *fp, poll_table *wait)
1515 {
1516         struct apm_user *as;
1517 
1518         as = fp->private_data;
1519         if (check_apm_user(as, "poll"))
1520                 return 0;
1521         poll_wait(fp, &apm_waitqueue, wait);
1522         if (!queue_empty(as))
1523                 return EPOLLIN | EPOLLRDNORM;
1524         return 0;
1525 }
1526 
1527 static long do_ioctl(struct file *filp, u_int cmd, u_long arg)
1528 {
1529         struct apm_user *as;
1530         int ret;
1531 
1532         as = filp->private_data;
1533         if (check_apm_user(as, "ioctl"))
1534                 return -EIO;
1535         if (!as->suser || !as->writer)
1536                 return -EPERM;
1537         switch (cmd) {
1538         case APM_IOC_STANDBY:
1539                 mutex_lock(&apm_mutex);
1540                 if (as->standbys_read > 0) {
1541                         as->standbys_read--;
1542                         as->standbys_pending--;
1543                         standbys_pending--;
1544                 } else
1545                         queue_event(APM_USER_STANDBY, as);
1546                 if (standbys_pending <= 0)
1547                         standby();
1548                 mutex_unlock(&apm_mutex);
1549                 break;
1550         case APM_IOC_SUSPEND:
1551                 mutex_lock(&apm_mutex);
1552                 if (as->suspends_read > 0) {
1553                         as->suspends_read--;
1554                         as->suspends_pending--;
1555                         suspends_pending--;
1556                 } else
1557                         queue_event(APM_USER_SUSPEND, as);
1558                 if (suspends_pending <= 0) {
1559                         ret = suspend(1);
1560                         mutex_unlock(&apm_mutex);
1561                 } else {
1562                         as->suspend_wait = 1;
1563                         mutex_unlock(&apm_mutex);
1564                         wait_event_interruptible(apm_suspend_waitqueue,
1565                                         as->suspend_wait == 0);
1566                         ret = as->suspend_result;
1567                 }
1568                 return ret;
1569         default:
1570                 return -ENOTTY;
1571         }
1572         return 0;
1573 }
1574 
1575 static int do_release(struct inode *inode, struct file *filp)
1576 {
1577         struct apm_user *as;
1578 
1579         as = filp->private_data;
1580         if (check_apm_user(as, "release"))
1581                 return 0;
1582         filp->private_data = NULL;
1583         if (as->standbys_pending > 0) {
1584                 standbys_pending -= as->standbys_pending;
1585                 if (standbys_pending <= 0)
1586                         standby();
1587         }
1588         if (as->suspends_pending > 0) {
1589                 suspends_pending -= as->suspends_pending;
1590                 if (suspends_pending <= 0)
1591                         (void) suspend(1);
1592         }
1593         spin_lock(&user_list_lock);
1594         if (user_list == as)
1595                 user_list = as->next;
1596         else {
1597                 struct apm_user *as1;
1598 
1599                 for (as1 = user_list;
1600                      (as1 != NULL) && (as1->next != as);
1601                      as1 = as1->next)
1602                         ;
1603                 if (as1 == NULL)
1604                         pr_err("filp not in user list\n");
1605                 else
1606                         as1->next = as->next;
1607         }
1608         spin_unlock(&user_list_lock);
1609         kfree(as);
1610         return 0;
1611 }
1612 
1613 static int do_open(struct inode *inode, struct file *filp)
1614 {
1615         struct apm_user *as;
1616 
1617         as = kmalloc(sizeof(*as), GFP_KERNEL);
1618         if (as == NULL)
1619                 return -ENOMEM;
1620 
1621         as->magic = APM_BIOS_MAGIC;
1622         as->event_tail = as->event_head = 0;
1623         as->suspends_pending = as->standbys_pending = 0;
1624         as->suspends_read = as->standbys_read = 0;
1625         /*
1626          * XXX - this is a tiny bit broken, when we consider BSD
1627          * process accounting. If the device is opened by root, we
1628          * instantly flag that we used superuser privs. Who knows,
1629          * we might close the device immediately without doing a
1630          * privileged operation -- cevans
1631          */
1632         as->suser = capable(CAP_SYS_ADMIN);
1633         as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
1634         as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
1635         spin_lock(&user_list_lock);
1636         as->next = user_list;
1637         user_list = as;
1638         spin_unlock(&user_list_lock);
1639         filp->private_data = as;
1640         return 0;
1641 }
1642 
1643 #ifdef CONFIG_PROC_FS
1644 static int proc_apm_show(struct seq_file *m, void *v)
1645 {
1646         unsigned short  bx;
1647         unsigned short  cx;
1648         unsigned short  dx;
1649         int             error;
1650         unsigned short  ac_line_status = 0xff;
1651         unsigned short  battery_status = 0xff;
1652         unsigned short  battery_flag   = 0xff;
1653         int             percentage     = -1;
1654         int             time_units     = -1;
1655         char            *units         = "?";
1656 
1657         if ((num_online_cpus() == 1) &&
1658             !(error = apm_get_power_status(&bx, &cx, &dx))) {
1659                 ac_line_status = (bx >> 8) & 0xff;
1660                 battery_status = bx & 0xff;
1661                 if ((cx & 0xff) != 0xff)
1662                         percentage = cx & 0xff;
1663 
1664                 if (apm_info.connection_version > 0x100) {
1665                         battery_flag = (cx >> 8) & 0xff;
1666                         if (dx != 0xffff) {
1667                                 units = (dx & 0x8000) ? "min" : "sec";
1668                                 time_units = dx & 0x7fff;
1669                         }
1670                 }
1671         }
1672         /* Arguments, with symbols from linux/apm_bios.h.  Information is
1673            from the Get Power Status (0x0a) call unless otherwise noted.
1674 
1675            0) Linux driver version (this will change if format changes)
1676            1) APM BIOS Version.  Usually 1.0, 1.1 or 1.2.
1677            2) APM flags from APM Installation Check (0x00):
1678               bit 0: APM_16_BIT_SUPPORT
1679               bit 1: APM_32_BIT_SUPPORT
1680               bit 2: APM_IDLE_SLOWS_CLOCK
1681               bit 3: APM_BIOS_DISABLED
1682               bit 4: APM_BIOS_DISENGAGED
1683            3) AC line status
1684               0x00: Off-line
1685               0x01: On-line
1686               0x02: On backup power (BIOS >= 1.1 only)
1687               0xff: Unknown
1688            4) Battery status
1689               0x00: High
1690               0x01: Low
1691               0x02: Critical
1692               0x03: Charging
1693               0x04: Selected battery not present (BIOS >= 1.2 only)
1694               0xff: Unknown
1695            5) Battery flag
1696               bit 0: High
1697               bit 1: Low
1698               bit 2: Critical
1699               bit 3: Charging
1700               bit 7: No system battery
1701               0xff: Unknown
1702            6) Remaining battery life (percentage of charge):
1703               0-100: valid
1704               -1: Unknown
1705            7) Remaining battery life (time units):
1706               Number of remaining minutes or seconds
1707               -1: Unknown
1708            8) min = minutes; sec = seconds */
1709 
1710         seq_printf(m, "%s %d.%d 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
1711                    driver_version,
1712                    (apm_info.bios.version >> 8) & 0xff,
1713                    apm_info.bios.version & 0xff,
1714                    apm_info.bios.flags,
1715                    ac_line_status,
1716                    battery_status,
1717                    battery_flag,
1718                    percentage,
1719                    time_units,
1720                    units);
1721         return 0;
1722 }
1723 #endif
1724 
1725 static int apm(void *unused)
1726 {
1727         unsigned short  bx;
1728         unsigned short  cx;
1729         unsigned short  dx;
1730         int             error;
1731         char            *power_stat;
1732         char            *bat_stat;
1733 
1734         /* 2002/08/01 - WT
1735          * This is to avoid random crashes at boot time during initialization
1736          * on SMP systems in case of "apm=power-off" mode. Seen on ASUS A7M266D.
1737          * Some bioses don't like being called from CPU != 0.
1738          * Method suggested by Ingo Molnar.
1739          */
1740         set_cpus_allowed_ptr(current, cpumask_of(0));
1741         BUG_ON(smp_processor_id() != 0);
1742 
1743         if (apm_info.connection_version == 0) {
1744                 apm_info.connection_version = apm_info.bios.version;
1745                 if (apm_info.connection_version > 0x100) {
1746                         /*
1747                          * We only support BIOSs up to version 1.2
1748                          */
1749                         if (apm_info.connection_version > 0x0102)
1750                                 apm_info.connection_version = 0x0102;
1751                         error = apm_driver_version(&apm_info.connection_version);
1752                         if (error != APM_SUCCESS) {
1753                                 apm_error("driver version", error);
1754                                 /* Fall back to an APM 1.0 connection. */
1755                                 apm_info.connection_version = 0x100;
1756                         }
1757                 }
1758         }
1759 
1760         if (debug)
1761                 printk(KERN_INFO "apm: Connection version %d.%d\n",
1762                         (apm_info.connection_version >> 8) & 0xff,
1763                         apm_info.connection_version & 0xff);
1764 
1765 #ifdef CONFIG_APM_DO_ENABLE
1766         if (apm_info.bios.flags & APM_BIOS_DISABLED) {
1767                 /*
1768                  * This call causes my NEC UltraLite Versa 33/C to hang if it
1769                  * is booted with PM disabled but not in the docking station.
1770                  * Unfortunate ...
1771                  */
1772                 error = apm_enable_power_management(1);
1773                 if (error) {
1774                         apm_error("enable power management", error);
1775                         return -1;
1776                 }
1777         }
1778 #endif
1779 
1780         if ((apm_info.bios.flags & APM_BIOS_DISENGAGED)
1781             && (apm_info.connection_version > 0x0100)) {
1782                 error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1783                 if (error) {
1784                         apm_error("engage power management", error);
1785                         return -1;
1786                 }
1787         }
1788 
1789         if (debug && (num_online_cpus() == 1 || smp)) {
1790                 error = apm_get_power_status(&bx, &cx, &dx);
1791                 if (error)
1792                         printk(KERN_INFO "apm: power status not available\n");
1793                 else {
1794                         switch ((bx >> 8) & 0xff) {
1795                         case 0:
1796                                 power_stat = "off line";
1797                                 break;
1798                         case 1:
1799                                 power_stat = "on line";
1800                                 break;
1801                         case 2:
1802                                 power_stat = "on backup power";
1803                                 break;
1804                         default:
1805                                 power_stat = "unknown";
1806                                 break;
1807                         }
1808                         switch (bx & 0xff) {
1809                         case 0:
1810                                 bat_stat = "high";
1811                                 break;
1812                         case 1:
1813                                 bat_stat = "low";
1814                                 break;
1815                         case 2:
1816                                 bat_stat = "critical";
1817                                 break;
1818                         case 3:
1819                                 bat_stat = "charging";
1820                                 break;
1821                         default:
1822                                 bat_stat = "unknown";
1823                                 break;
1824                         }
1825                         printk(KERN_INFO
1826                                "apm: AC %s, battery status %s, battery life ",
1827                                power_stat, bat_stat);
1828                         if ((cx & 0xff) == 0xff)
1829                                 printk("unknown\n");
1830                         else
1831                                 printk("%d%%\n", cx & 0xff);
1832                         if (apm_info.connection_version > 0x100) {
1833                                 printk(KERN_INFO
1834                                        "apm: battery flag 0x%02x, battery life ",
1835                                        (cx >> 8) & 0xff);
1836                                 if (dx == 0xffff)
1837                                         printk("unknown\n");
1838                                 else
1839                                         printk("%d %s\n", dx & 0x7fff,
1840                                                (dx & 0x8000) ?
1841                                                "minutes" : "seconds");
1842                         }
1843                 }
1844         }
1845 
1846         /* Install our power off handler.. */
1847         if (power_off)
1848                 pm_power_off = apm_power_off;
1849 
1850         if (num_online_cpus() == 1 || smp) {
1851 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1852                 console_blank_hook = apm_console_blank;
1853 #endif
1854                 apm_mainloop();
1855 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1856                 console_blank_hook = NULL;
1857 #endif
1858         }
1859 
1860         return 0;
1861 }
1862 
1863 #ifndef MODULE
1864 static int __init apm_setup(char *str)
1865 {
1866         int invert;
1867 
1868         while ((str != NULL) && (*str != '\0')) {
1869                 if (strncmp(str, "off", 3) == 0)
1870                         apm_disabled = 1;
1871                 if (strncmp(str, "on", 2) == 0)
1872                         apm_disabled = 0;
1873                 if ((strncmp(str, "bounce-interval=", 16) == 0) ||
1874                     (strncmp(str, "bounce_interval=", 16) == 0))
1875                         bounce_interval = simple_strtol(str + 16, NULL, 0);
1876                 if ((strncmp(str, "idle-threshold=", 15) == 0) ||
1877                     (strncmp(str, "idle_threshold=", 15) == 0))
1878                         idle_threshold = simple_strtol(str + 15, NULL, 0);
1879                 if ((strncmp(str, "idle-period=", 12) == 0) ||
1880                     (strncmp(str, "idle_period=", 12) == 0))
1881                         idle_period = simple_strtol(str + 12, NULL, 0);
1882                 invert = (strncmp(str, "no-", 3) == 0) ||
1883                         (strncmp(str, "no_", 3) == 0);
1884                 if (invert)
1885                         str += 3;
1886                 if (strncmp(str, "debug", 5) == 0)
1887                         debug = !invert;
1888                 if ((strncmp(str, "power-off", 9) == 0) ||
1889                     (strncmp(str, "power_off", 9) == 0))
1890                         power_off = !invert;
1891                 if (strncmp(str, "smp", 3) == 0) {
1892                         smp = !invert;
1893                         idle_threshold = 100;
1894                 }
1895                 if ((strncmp(str, "allow-ints", 10) == 0) ||
1896                     (strncmp(str, "allow_ints", 10) == 0))
1897                         apm_info.allow_ints = !invert;
1898                 if ((strncmp(str, "broken-psr", 10) == 0) ||
1899                     (strncmp(str, "broken_psr", 10) == 0))
1900                         apm_info.get_power_status_broken = !invert;
1901                 if ((strncmp(str, "realmode-power-off", 18) == 0) ||
1902                     (strncmp(str, "realmode_power_off", 18) == 0))
1903                         apm_info.realmode_power_off = !invert;
1904                 str = strchr(str, ',');
1905                 if (str != NULL)
1906                         str += strspn(str, ", \t");
1907         }
1908         return 1;
1909 }
1910 
1911 __setup("apm=", apm_setup);
1912 #endif
1913 
1914 static const struct file_operations apm_bios_fops = {
1915         .owner          = THIS_MODULE,
1916         .read           = do_read,
1917         .poll           = do_poll,
1918         .unlocked_ioctl = do_ioctl,
1919         .open           = do_open,
1920         .release        = do_release,
1921         .llseek         = noop_llseek,
1922 };
1923 
1924 static struct miscdevice apm_device = {
1925         APM_MINOR_DEV,
1926         "apm_bios",
1927         &apm_bios_fops
1928 };
1929 
1930 
1931 /* Simple "print if true" callback */
1932 static int __init print_if_true(const struct dmi_system_id *d)
1933 {
1934         printk("%s\n", d->ident);
1935         return 0;
1936 }
1937 
1938 /*
1939  * Some Bioses enable the PS/2 mouse (touchpad) at resume, even if it was
1940  * disabled before the suspend. Linux used to get terribly confused by that.
1941  */
1942 static int __init broken_ps2_resume(const struct dmi_system_id *d)
1943 {
1944         printk(KERN_INFO "%s machine detected. Mousepad Resume Bug "
1945                "workaround hopefully not needed.\n", d->ident);
1946         return 0;
1947 }
1948 
1949 /* Some bioses have a broken protected mode poweroff and need to use realmode */
1950 static int __init set_realmode_power_off(const struct dmi_system_id *d)
1951 {
1952         if (apm_info.realmode_power_off == 0) {
1953                 apm_info.realmode_power_off = 1;
1954                 printk(KERN_INFO "%s bios detected. "
1955                        "Using realmode poweroff only.\n", d->ident);
1956         }
1957         return 0;
1958 }
1959 
1960 /* Some laptops require interrupts to be enabled during APM calls */
1961 static int __init set_apm_ints(const struct dmi_system_id *d)
1962 {
1963         if (apm_info.allow_ints == 0) {
1964                 apm_info.allow_ints = 1;
1965                 printk(KERN_INFO "%s machine detected. "
1966                        "Enabling interrupts during APM calls.\n", d->ident);
1967         }
1968         return 0;
1969 }
1970 
1971 /* Some APM bioses corrupt memory or just plain do not work */
1972 static int __init apm_is_horked(const struct dmi_system_id *d)
1973 {
1974         if (apm_info.disabled == 0) {
1975                 apm_info.disabled = 1;
1976                 printk(KERN_INFO "%s machine detected. "
1977                        "Disabling APM.\n", d->ident);
1978         }
1979         return 0;
1980 }
1981 
1982 static int __init apm_is_horked_d850md(const struct dmi_system_id *d)
1983 {
1984         if (apm_info.disabled == 0) {
1985                 apm_info.disabled = 1;
1986                 printk(KERN_INFO "%s machine detected. "
1987                        "Disabling APM.\n", d->ident);
1988                 printk(KERN_INFO "This bug is fixed in bios P15 which is available for\n");
1989                 printk(KERN_INFO "download from support.intel.com\n");
1990         }
1991         return 0;
1992 }
1993 
1994 /* Some APM bioses hang on APM idle calls */
1995 static int __init apm_likes_to_melt(const struct dmi_system_id *d)
1996 {
1997         if (apm_info.forbid_idle == 0) {
1998                 apm_info.forbid_idle = 1;
1999                 printk(KERN_INFO "%s machine detected. "
2000                        "Disabling APM idle calls.\n", d->ident);
2001         }
2002         return 0;
2003 }
2004 
2005 /*
2006  *  Check for clue free BIOS implementations who use
2007  *  the following QA technique
2008  *
2009  *      [ Write BIOS Code ]<------
2010  *               |                ^
2011  *      < Does it Compile >----N--
2012  *               |Y               ^
2013  *      < Does it Boot Win98 >-N--
2014  *               |Y
2015  *           [Ship It]
2016  *
2017  *      Phoenix A04  08/24/2000 is known bad (Dell Inspiron 5000e)
2018  *      Phoenix A07  09/29/2000 is known good (Dell Inspiron 5000)
2019  */
2020 static int __init broken_apm_power(const struct dmi_system_id *d)
2021 {
2022         apm_info.get_power_status_broken = 1;
2023         printk(KERN_WARNING "BIOS strings suggest APM bugs, "
2024                "disabling power status reporting.\n");
2025         return 0;
2026 }
2027 
2028 /*
2029  * This bios swaps the APM minute reporting bytes over (Many sony laptops
2030  * have this problem).
2031  */
2032 static int __init swab_apm_power_in_minutes(const struct dmi_system_id *d)
2033 {
2034         apm_info.get_power_status_swabinminutes = 1;
2035         printk(KERN_WARNING "BIOS strings suggest APM reports battery life "
2036                "in minutes and wrong byte order.\n");
2037         return 0;
2038 }
2039 
2040 static const struct dmi_system_id apm_dmi_table[] __initconst = {
2041         {
2042                 print_if_true,
2043                 KERN_WARNING "IBM T23 - BIOS 1.03b+ and controller firmware 1.02+ may be needed for Linux APM.",
2044                 {       DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
2045                         DMI_MATCH(DMI_BIOS_VERSION, "1AET38WW (1.01b)"), },
2046         },
2047         {       /* Handle problems with APM on the C600 */
2048                 broken_ps2_resume, "Dell Latitude C600",
2049                 {       DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
2050                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C600"), },
2051         },
2052         {       /* Allow interrupts during suspend on Dell Latitude laptops*/
2053                 set_apm_ints, "Dell Latitude",
2054                 {       DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2055                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C510"), }
2056         },
2057         {       /* APM crashes */
2058                 apm_is_horked, "Dell Inspiron 2500",
2059                 {       DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2060                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2061                         DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2062                         DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2063         },
2064         {       /* Allow interrupts during suspend on Dell Inspiron laptops*/
2065                 set_apm_ints, "Dell Inspiron", {
2066                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2067                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 4000"), },
2068         },
2069         {       /* Handle problems with APM on Inspiron 5000e */
2070                 broken_apm_power, "Dell Inspiron 5000e",
2071                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2072                         DMI_MATCH(DMI_BIOS_VERSION, "A04"),
2073                         DMI_MATCH(DMI_BIOS_DATE, "08/24/2000"), },
2074         },
2075         {       /* Handle problems with APM on Inspiron 2500 */
2076                 broken_apm_power, "Dell Inspiron 2500",
2077                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2078                         DMI_MATCH(DMI_BIOS_VERSION, "A12"),
2079                         DMI_MATCH(DMI_BIOS_DATE, "02/04/2002"), },
2080         },
2081         {       /* APM crashes */
2082                 apm_is_horked, "Dell Dimension 4100",
2083                 {       DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2084                         DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"),
2085                         DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2086                         DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2087         },
2088         {       /* Allow interrupts during suspend on Compaq Laptops*/
2089                 set_apm_ints, "Compaq 12XL125",
2090                 {       DMI_MATCH(DMI_SYS_VENDOR, "Compaq"),
2091                         DMI_MATCH(DMI_PRODUCT_NAME, "Compaq PC"),
2092                         DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2093                         DMI_MATCH(DMI_BIOS_VERSION, "4.06"), },
2094         },
2095         {       /* Allow interrupts during APM or the clock goes slow */
2096                 set_apm_ints, "ASUSTeK",
2097                 {       DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
2098                         DMI_MATCH(DMI_PRODUCT_NAME, "L8400K series Notebook PC"), },
2099         },
2100         {       /* APM blows on shutdown */
2101                 apm_is_horked, "ABIT KX7-333[R]",
2102                 {       DMI_MATCH(DMI_BOARD_VENDOR, "ABIT"),
2103                         DMI_MATCH(DMI_BOARD_NAME, "VT8367-8233A (KX7-333[R])"), },
2104         },
2105         {       /* APM crashes */
2106                 apm_is_horked, "Trigem Delhi3",
2107                 {       DMI_MATCH(DMI_SYS_VENDOR, "TriGem Computer, Inc"),
2108                         DMI_MATCH(DMI_PRODUCT_NAME, "Delhi3"), },
2109         },
2110         {       /* APM crashes */
2111                 apm_is_horked, "Fujitsu-Siemens",
2112                 {       DMI_MATCH(DMI_BIOS_VENDOR, "hoenix/FUJITSU SIEMENS"),
2113                         DMI_MATCH(DMI_BIOS_VERSION, "Version1.01"), },
2114         },
2115         {       /* APM crashes */
2116                 apm_is_horked_d850md, "Intel D850MD",
2117                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2118                         DMI_MATCH(DMI_BIOS_VERSION, "MV85010A.86A.0016.P07.0201251536"), },
2119         },
2120         {       /* APM crashes */
2121                 apm_is_horked, "Intel D810EMO",
2122                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2123                         DMI_MATCH(DMI_BIOS_VERSION, "MO81010A.86A.0008.P04.0004170800"), },
2124         },
2125         {       /* APM crashes */
2126                 apm_is_horked, "Dell XPS-Z",
2127                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2128                         DMI_MATCH(DMI_BIOS_VERSION, "A11"),
2129                         DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"), },
2130         },
2131         {       /* APM crashes */
2132                 apm_is_horked, "Sharp PC-PJ/AX",
2133                 {       DMI_MATCH(DMI_SYS_VENDOR, "SHARP"),
2134                         DMI_MATCH(DMI_PRODUCT_NAME, "PC-PJ/AX"),
2135                         DMI_MATCH(DMI_BIOS_VENDOR, "SystemSoft"),
2136                         DMI_MATCH(DMI_BIOS_VERSION, "Version R2.08"), },
2137         },
2138         {       /* APM crashes */
2139                 apm_is_horked, "Dell Inspiron 2500",
2140                 {       DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2141                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2142                         DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2143                         DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2144         },
2145         {       /* APM idle hangs */
2146                 apm_likes_to_melt, "Jabil AMD",
2147                 {       DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2148                         DMI_MATCH(DMI_BIOS_VERSION, "0AASNP06"), },
2149         },
2150         {       /* APM idle hangs */
2151                 apm_likes_to_melt, "AMI Bios",
2152                 {       DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2153                         DMI_MATCH(DMI_BIOS_VERSION, "0AASNP05"), },
2154         },
2155         {       /* Handle problems with APM on Sony Vaio PCG-N505X(DE) */
2156                 swab_apm_power_in_minutes, "Sony VAIO",
2157                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2158                         DMI_MATCH(DMI_BIOS_VERSION, "R0206H"),
2159                         DMI_MATCH(DMI_BIOS_DATE, "08/23/99"), },
2160         },
2161         {       /* Handle problems with APM on Sony Vaio PCG-N505VX */
2162                 swab_apm_power_in_minutes, "Sony VAIO",
2163                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2164                         DMI_MATCH(DMI_BIOS_VERSION, "W2K06H0"),
2165                         DMI_MATCH(DMI_BIOS_DATE, "02/03/00"), },
2166         },
2167         {       /* Handle problems with APM on Sony Vaio PCG-XG29 */
2168                 swab_apm_power_in_minutes, "Sony VAIO",
2169                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2170                         DMI_MATCH(DMI_BIOS_VERSION, "R0117A0"),
2171                         DMI_MATCH(DMI_BIOS_DATE, "04/25/00"), },
2172         },
2173         {       /* Handle problems with APM on Sony Vaio PCG-Z600NE */
2174                 swab_apm_power_in_minutes, "Sony VAIO",
2175                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2176                         DMI_MATCH(DMI_BIOS_VERSION, "R0121Z1"),
2177                         DMI_MATCH(DMI_BIOS_DATE, "05/11/00"), },
2178         },
2179         {       /* Handle problems with APM on Sony Vaio PCG-Z600NE */
2180                 swab_apm_power_in_minutes, "Sony VAIO",
2181                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2182                         DMI_MATCH(DMI_BIOS_VERSION, "WME01Z1"),
2183                         DMI_MATCH(DMI_BIOS_DATE, "08/11/00"), },
2184         },
2185         {       /* Handle problems with APM on Sony Vaio PCG-Z600LEK(DE) */
2186                 swab_apm_power_in_minutes, "Sony VAIO",
2187                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2188                         DMI_MATCH(DMI_BIOS_VERSION, "R0206Z3"),
2189                         DMI_MATCH(DMI_BIOS_DATE, "12/25/00"), },
2190         },
2191         {       /* Handle problems with APM on Sony Vaio PCG-Z505LS */
2192                 swab_apm_power_in_minutes, "Sony VAIO",
2193                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2194                         DMI_MATCH(DMI_BIOS_VERSION, "R0203D0"),
2195                         DMI_MATCH(DMI_BIOS_DATE, "05/12/00"), },
2196         },
2197         {       /* Handle problems with APM on Sony Vaio PCG-Z505LS */
2198                 swab_apm_power_in_minutes, "Sony VAIO",
2199                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2200                         DMI_MATCH(DMI_BIOS_VERSION, "R0203Z3"),
2201                         DMI_MATCH(DMI_BIOS_DATE, "08/25/00"), },
2202         },
2203         {       /* Handle problems with APM on Sony Vaio PCG-Z505LS (with updated BIOS) */
2204                 swab_apm_power_in_minutes, "Sony VAIO",
2205                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2206                         DMI_MATCH(DMI_BIOS_VERSION, "R0209Z3"),
2207                         DMI_MATCH(DMI_BIOS_DATE, "05/12/01"), },
2208         },
2209         {       /* Handle problems with APM on Sony Vaio PCG-F104K */
2210                 swab_apm_power_in_minutes, "Sony VAIO",
2211                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2212                         DMI_MATCH(DMI_BIOS_VERSION, "R0204K2"),
2213                         DMI_MATCH(DMI_BIOS_DATE, "08/28/00"), },
2214         },
2215 
2216         {       /* Handle problems with APM on Sony Vaio PCG-C1VN/C1VE */
2217                 swab_apm_power_in_minutes, "Sony VAIO",
2218                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2219                         DMI_MATCH(DMI_BIOS_VERSION, "R0208P1"),
2220                         DMI_MATCH(DMI_BIOS_DATE, "11/09/00"), },
2221         },
2222         {       /* Handle problems with APM on Sony Vaio PCG-C1VE */
2223                 swab_apm_power_in_minutes, "Sony VAIO",
2224                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2225                         DMI_MATCH(DMI_BIOS_VERSION, "R0204P1"),
2226                         DMI_MATCH(DMI_BIOS_DATE, "09/12/00"), },
2227         },
2228         {       /* Handle problems with APM on Sony Vaio PCG-C1VE */
2229                 swab_apm_power_in_minutes, "Sony VAIO",
2230                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2231                         DMI_MATCH(DMI_BIOS_VERSION, "WXPO1Z3"),
2232                         DMI_MATCH(DMI_BIOS_DATE, "10/26/01"), },
2233         },
2234         {       /* broken PM poweroff bios */
2235                 set_realmode_power_off, "Award Software v4.60 PGMA",
2236                 {       DMI_MATCH(DMI_BIOS_VENDOR, "Award Software International, Inc."),
2237                         DMI_MATCH(DMI_BIOS_VERSION, "4.60 PGMA"),
2238                         DMI_MATCH(DMI_BIOS_DATE, "134526184"), },
2239         },
2240 
2241         /* Generic per vendor APM settings  */
2242 
2243         {       /* Allow interrupts during suspend on IBM laptops */
2244                 set_apm_ints, "IBM",
2245                 {       DMI_MATCH(DMI_SYS_VENDOR, "IBM"), },
2246         },
2247 
2248         { }
2249 };
2250 
2251 /*
2252  * Just start the APM thread. We do NOT want to do APM BIOS
2253  * calls from anything but the APM thread, if for no other reason
2254  * than the fact that we don't trust the APM BIOS. This way,
2255  * most common APM BIOS problems that lead to protection errors
2256  * etc will have at least some level of being contained...
2257  *
2258  * In short, if something bad happens, at least we have a choice
2259  * of just killing the apm thread..
2260  */
2261 static int __init apm_init(void)
2262 {
2263         struct desc_struct *gdt;
2264         int err;
2265 
2266         dmi_check_system(apm_dmi_table);
2267 
2268         if (apm_info.bios.version == 0 || machine_is_olpc()) {
2269                 printk(KERN_INFO "apm: BIOS not found.\n");
2270                 return -ENODEV;
2271         }
2272         printk(KERN_INFO
2273                "apm: BIOS version %d.%d Flags 0x%02x (Driver version %s)\n",
2274                ((apm_info.bios.version >> 8) & 0xff),
2275                (apm_info.bios.version & 0xff),
2276                apm_info.bios.flags,
2277                driver_version);
2278         if ((apm_info.bios.flags & APM_32_BIT_SUPPORT) == 0) {
2279                 printk(KERN_INFO "apm: no 32 bit BIOS support\n");
2280                 return -ENODEV;
2281         }
2282 
2283         if (allow_ints)
2284                 apm_info.allow_ints = 1;
2285         if (broken_psr)
2286                 apm_info.get_power_status_broken = 1;
2287         if (realmode_power_off)
2288                 apm_info.realmode_power_off = 1;
2289         /* User can override, but default is to trust DMI */
2290         if (apm_disabled != -1)
2291                 apm_info.disabled = apm_disabled;
2292 
2293         /*
2294          * Fix for the Compaq Contura 3/25c which reports BIOS version 0.1
2295          * but is reportedly a 1.0 BIOS.
2296          */
2297         if (apm_info.bios.version == 0x001)
2298                 apm_info.bios.version = 0x100;
2299 
2300         /* BIOS < 1.2 doesn't set cseg_16_len */
2301         if (apm_info.bios.version < 0x102)
2302                 apm_info.bios.cseg_16_len = 0; /* 64k */
2303 
2304         if (debug) {
2305                 printk(KERN_INFO "apm: entry %x:%x cseg16 %x dseg %x",
2306                         apm_info.bios.cseg, apm_info.bios.offset,
2307                         apm_info.bios.cseg_16, apm_info.bios.dseg);
2308                 if (apm_info.bios.version > 0x100)
2309                         printk(" cseg len %x, dseg len %x",
2310                                 apm_info.bios.cseg_len,
2311                                 apm_info.bios.dseg_len);
2312                 if (apm_info.bios.version > 0x101)
2313                         printk(" cseg16 len %x", apm_info.bios.cseg_16_len);
2314                 printk("\n");
2315         }
2316 
2317         if (apm_info.disabled) {
2318                 pr_notice("disabled on user request.\n");
2319                 return -ENODEV;
2320         }
2321         if ((num_online_cpus() > 1) && !power_off && !smp) {
2322                 pr_notice("disabled - APM is not SMP safe.\n");
2323                 apm_info.disabled = 1;
2324                 return -ENODEV;
2325         }
2326         if (!acpi_disabled) {
2327                 pr_notice("overridden by ACPI.\n");
2328                 apm_info.disabled = 1;
2329                 return -ENODEV;
2330         }
2331 
2332         /*
2333          * Set up the long jump entry point to the APM BIOS, which is called
2334          * from inline assembly.
2335          */
2336         apm_bios_entry.offset = apm_info.bios.offset;
2337         apm_bios_entry.segment = APM_CS;
2338 
2339         /*
2340          * The APM 1.1 BIOS is supposed to provide limit information that it
2341          * recognizes.  Many machines do this correctly, but many others do
2342          * not restrict themselves to their claimed limit.  When this happens,
2343          * they will cause a segmentation violation in the kernel at boot time.
2344          * Most BIOS's, however, will respect a 64k limit, so we use that.
2345          *
2346          * Note we only set APM segments on CPU zero, since we pin the APM
2347          * code to that CPU.
2348          */
2349         gdt = get_cpu_gdt_rw(0);
2350         set_desc_base(&gdt[APM_CS >> 3],
2351                  (unsigned long)__va((unsigned long)apm_info.bios.cseg << 4));
2352         set_desc_base(&gdt[APM_CS_16 >> 3],
2353                  (unsigned long)__va((unsigned long)apm_info.bios.cseg_16 << 4));
2354         set_desc_base(&gdt[APM_DS >> 3],
2355                  (unsigned long)__va((unsigned long)apm_info.bios.dseg << 4));
2356 
2357         proc_create_single("apm", 0, NULL, proc_apm_show);
2358 
2359         kapmd_task = kthread_create(apm, NULL, "kapmd");
2360         if (IS_ERR(kapmd_task)) {
2361                 pr_err("disabled - Unable to start kernel thread\n");
2362                 err = PTR_ERR(kapmd_task);
2363                 kapmd_task = NULL;
2364                 remove_proc_entry("apm", NULL);
2365                 return err;
2366         }
2367         wake_up_process(kapmd_task);
2368 
2369         if (num_online_cpus() > 1 && !smp) {
2370                 printk(KERN_NOTICE
2371                        "apm: disabled - APM is not SMP safe (power off active).\n");
2372                 return 0;
2373         }
2374 
2375         /*
2376          * Note we don't actually care if the misc_device cannot be registered.
2377          * this driver can do its job without it, even if userspace can't
2378          * control it.  just log the error
2379          */
2380         if (misc_register(&apm_device))
2381                 printk(KERN_WARNING "apm: Could not register misc device.\n");
2382 
2383         if (HZ != 100)
2384                 idle_period = (idle_period * HZ) / 100;
2385         if (idle_threshold < 100) {
2386                 cpuidle_poll_state_init(&apm_idle_driver);
2387                 if (!cpuidle_register_driver(&apm_idle_driver))
2388                         if (cpuidle_register_device(&apm_cpuidle_device))
2389                                 cpuidle_unregister_driver(&apm_idle_driver);
2390         }
2391 
2392         return 0;
2393 }
2394 
2395 static void __exit apm_exit(void)
2396 {
2397         int error;
2398 
2399         cpuidle_unregister_device(&apm_cpuidle_device);
2400         cpuidle_unregister_driver(&apm_idle_driver);
2401 
2402         if (((apm_info.bios.flags & APM_BIOS_DISENGAGED) == 0)
2403             && (apm_info.connection_version > 0x0100)) {
2404                 error = apm_engage_power_management(APM_DEVICE_ALL, 0);
2405                 if (error)
2406                         apm_error("disengage power management", error);
2407         }
2408         misc_deregister(&apm_device);
2409         remove_proc_entry("apm", NULL);
2410         if (power_off)
2411                 pm_power_off = NULL;
2412         if (kapmd_task) {
2413                 kthread_stop(kapmd_task);
2414                 kapmd_task = NULL;
2415         }
2416 }
2417 
2418 module_init(apm_init);
2419 module_exit(apm_exit);
2420 
2421 MODULE_AUTHOR("Stephen Rothwell");
2422 MODULE_DESCRIPTION("Advanced Power Management");
2423 MODULE_LICENSE("GPL");
2424 module_param(debug, bool, 0644);
2425 MODULE_PARM_DESC(debug, "Enable debug mode");
2426 module_param(power_off, bool, 0444);
2427 MODULE_PARM_DESC(power_off, "Enable power off");
2428 module_param(bounce_interval, int, 0444);
2429 MODULE_PARM_DESC(bounce_interval,
2430                 "Set the number of ticks to ignore suspend bounces");
2431 module_param(allow_ints, bool, 0444);
2432 MODULE_PARM_DESC(allow_ints, "Allow interrupts during BIOS calls");
2433 module_param(broken_psr, bool, 0444);
2434 MODULE_PARM_DESC(broken_psr, "BIOS has a broken GetPowerStatus call");
2435 module_param(realmode_power_off, bool, 0444);
2436 MODULE_PARM_DESC(realmode_power_off,
2437                 "Switch to real mode before powering off");
2438 module_param(idle_threshold, int, 0444);
2439 MODULE_PARM_DESC(idle_threshold,
2440         "System idle percentage above which to make APM BIOS idle calls");
2441 module_param(idle_period, int, 0444);
2442 MODULE_PARM_DESC(idle_period,
2443         "Period (in sec/100) over which to calculate the idle percentage");
2444 module_param(smp, bool, 0444);
2445 MODULE_PARM_DESC(smp,
2446         "Set this to enable APM use on an SMP platform. Use with caution on older systems");
2447 MODULE_ALIAS_MISCDEV(APM_MINOR_DEV);
2448 

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