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Linux/arch/x86/kernel/apm_32.c

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

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