xref: /openbmc/linux/arch/x86/kernel/apm_32.c (revision 261a9af6)
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 #include <linux/module.h>
205 
206 #include <linux/poll.h>
207 #include <linux/types.h>
208 #include <linux/stddef.h>
209 #include <linux/timer.h>
210 #include <linux/fcntl.h>
211 #include <linux/slab.h>
212 #include <linux/stat.h>
213 #include <linux/proc_fs.h>
214 #include <linux/seq_file.h>
215 #include <linux/miscdevice.h>
216 #include <linux/apm_bios.h>
217 #include <linux/init.h>
218 #include <linux/time.h>
219 #include <linux/sched.h>
220 #include <linux/pm.h>
221 #include <linux/capability.h>
222 #include <linux/device.h>
223 #include <linux/kernel.h>
224 #include <linux/freezer.h>
225 #include <linux/smp.h>
226 #include <linux/dmi.h>
227 #include <linux/suspend.h>
228 #include <linux/kthread.h>
229 #include <linux/jiffies.h>
230 #include <linux/acpi.h>
231 #include <linux/syscore_ops.h>
232 
233 #include <asm/system.h>
234 #include <asm/uaccess.h>
235 #include <asm/desc.h>
236 #include <asm/i8253.h>
237 #include <asm/olpc.h>
238 #include <asm/paravirt.h>
239 #include <asm/reboot.h>
240 
241 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
242 extern int (*console_blank_hook)(int);
243 #endif
244 
245 /*
246  * The apm_bios device is one of the misc char devices.
247  * This is its minor number.
248  */
249 #define	APM_MINOR_DEV	134
250 
251 /*
252  * See Documentation/Config.help for the configuration options.
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 #warning deprecated CONFIG_APM_CPU_IDLE will be deleted in 2012
365 #define DEFAULT_IDLE_THRESHOLD	95
366 #else
367 #define DEFAULT_IDLE_THRESHOLD	100
368 #endif
369 #define DEFAULT_IDLE_PERIOD	(100 / 3)
370 
371 /*
372  * Local variables
373  */
374 static struct {
375 	unsigned long	offset;
376 	unsigned short	segment;
377 } apm_bios_entry;
378 static int clock_slowed;
379 static int idle_threshold __read_mostly = DEFAULT_IDLE_THRESHOLD;
380 static int idle_period __read_mostly = DEFAULT_IDLE_PERIOD;
381 static int set_pm_idle;
382 static int suspends_pending;
383 static int standbys_pending;
384 static int ignore_sys_suspend;
385 static int ignore_normal_resume;
386 static int bounce_interval __read_mostly = DEFAULT_BOUNCE_INTERVAL;
387 
388 static int debug __read_mostly;
389 static int smp __read_mostly;
390 static int apm_disabled = -1;
391 #ifdef CONFIG_SMP
392 static int power_off;
393 #else
394 static int power_off = 1;
395 #endif
396 static int realmode_power_off;
397 #ifdef CONFIG_APM_ALLOW_INTS
398 static int allow_ints = 1;
399 #else
400 static int allow_ints;
401 #endif
402 static int broken_psr;
403 
404 static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
405 static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
406 static struct apm_user *user_list;
407 static DEFINE_SPINLOCK(user_list_lock);
408 static DEFINE_MUTEX(apm_mutex);
409 
410 /*
411  * Set up a segment that references the real mode segment 0x40
412  * that extends up to the end of page zero (that we have reserved).
413  * This is for buggy BIOS's that refer to (real mode) segment 0x40
414  * even though they are called in protected mode.
415  */
416 static struct desc_struct bad_bios_desc = GDT_ENTRY_INIT(0x4092,
417 			(unsigned long)__va(0x400UL), PAGE_SIZE - 0x400 - 1);
418 
419 static const char driver_version[] = "1.16ac";	/* no spaces */
420 
421 static struct task_struct *kapmd_task;
422 
423 /*
424  *	APM event names taken from the APM 1.2 specification. These are
425  *	the message codes that the BIOS uses to tell us about events
426  */
427 static const char * const apm_event_name[] = {
428 	"system standby",
429 	"system suspend",
430 	"normal resume",
431 	"critical resume",
432 	"low battery",
433 	"power status change",
434 	"update time",
435 	"critical suspend",
436 	"user standby",
437 	"user suspend",
438 	"system standby resume",
439 	"capabilities change"
440 };
441 #define NR_APM_EVENT_NAME ARRAY_SIZE(apm_event_name)
442 
443 typedef struct lookup_t {
444 	int	key;
445 	char 	*msg;
446 } lookup_t;
447 
448 /*
449  *	The BIOS returns a set of standard error codes in AX when the
450  *	carry flag is set.
451  */
452 
453 static const lookup_t error_table[] = {
454 /* N/A	{ APM_SUCCESS,		"Operation succeeded" }, */
455 	{ APM_DISABLED,		"Power management disabled" },
456 	{ APM_CONNECTED,	"Real mode interface already connected" },
457 	{ APM_NOT_CONNECTED,	"Interface not connected" },
458 	{ APM_16_CONNECTED,	"16 bit interface already connected" },
459 /* N/A	{ APM_16_UNSUPPORTED,	"16 bit interface not supported" }, */
460 	{ APM_32_CONNECTED,	"32 bit interface already connected" },
461 	{ APM_32_UNSUPPORTED,	"32 bit interface not supported" },
462 	{ APM_BAD_DEVICE,	"Unrecognized device ID" },
463 	{ APM_BAD_PARAM,	"Parameter out of range" },
464 	{ APM_NOT_ENGAGED,	"Interface not engaged" },
465 	{ APM_BAD_FUNCTION,     "Function not supported" },
466 	{ APM_RESUME_DISABLED,	"Resume timer disabled" },
467 	{ APM_BAD_STATE,	"Unable to enter requested state" },
468 /* N/A	{ APM_NO_EVENTS,	"No events pending" }, */
469 	{ APM_NO_ERROR,		"BIOS did not set a return code" },
470 	{ APM_NOT_PRESENT,	"No APM present" }
471 };
472 #define ERROR_COUNT	ARRAY_SIZE(error_table)
473 
474 /**
475  *	apm_error	-	display an APM error
476  *	@str: information string
477  *	@err: APM BIOS return code
478  *
479  *	Write a meaningful log entry to the kernel log in the event of
480  *	an APM error.  Note that this also handles (negative) kernel errors.
481  */
482 
483 static void apm_error(char *str, int err)
484 {
485 	int i;
486 
487 	for (i = 0; i < ERROR_COUNT; i++)
488 		if (error_table[i].key == err)
489 			break;
490 	if (i < ERROR_COUNT)
491 		printk(KERN_NOTICE "apm: %s: %s\n", str, error_table[i].msg);
492 	else if (err < 0)
493 		printk(KERN_NOTICE "apm: %s: linux error code %i\n", str, err);
494 	else
495 		printk(KERN_NOTICE "apm: %s: unknown error code %#2.2x\n",
496 		       str, err);
497 }
498 
499 /*
500  * These are the actual BIOS calls.  Depending on APM_ZERO_SEGS and
501  * apm_info.allow_ints, we are being really paranoid here!  Not only
502  * are interrupts disabled, but all the segment registers (except SS)
503  * are saved and zeroed this means that if the BIOS tries to reference
504  * any data without explicitly loading the segment registers, the kernel
505  * will fault immediately rather than have some unforeseen circumstances
506  * for the rest of the kernel.  And it will be very obvious!  :-) Doing
507  * this depends on CS referring to the same physical memory as DS so that
508  * DS can be zeroed before the call. Unfortunately, we can't do anything
509  * about the stack segment/pointer.  Also, we tell the compiler that
510  * everything could change.
511  *
512  * Also, we KNOW that for the non error case of apm_bios_call, there
513  * is no useful data returned in the low order 8 bits of eax.
514  */
515 
516 static inline unsigned long __apm_irq_save(void)
517 {
518 	unsigned long flags;
519 	local_save_flags(flags);
520 	if (apm_info.allow_ints) {
521 		if (irqs_disabled_flags(flags))
522 			local_irq_enable();
523 	} else
524 		local_irq_disable();
525 
526 	return flags;
527 }
528 
529 #define apm_irq_save(flags) \
530 	do { flags = __apm_irq_save(); } while (0)
531 
532 static inline void apm_irq_restore(unsigned long flags)
533 {
534 	if (irqs_disabled_flags(flags))
535 		local_irq_disable();
536 	else if (irqs_disabled())
537 		local_irq_enable();
538 }
539 
540 #ifdef APM_ZERO_SEGS
541 #	define APM_DECL_SEGS \
542 		unsigned int saved_fs; unsigned int saved_gs;
543 #	define APM_DO_SAVE_SEGS \
544 		savesegment(fs, saved_fs); savesegment(gs, saved_gs)
545 #	define APM_DO_RESTORE_SEGS \
546 		loadsegment(fs, saved_fs); loadsegment(gs, saved_gs)
547 #else
548 #	define APM_DECL_SEGS
549 #	define APM_DO_SAVE_SEGS
550 #	define APM_DO_RESTORE_SEGS
551 #endif
552 
553 struct apm_bios_call {
554 	u32 func;
555 	/* In and out */
556 	u32 ebx;
557 	u32 ecx;
558 	/* Out only */
559 	u32 eax;
560 	u32 edx;
561 	u32 esi;
562 
563 	/* Error: -ENOMEM, or bits 8-15 of eax */
564 	int err;
565 };
566 
567 /**
568  *	__apm_bios_call - Make an APM BIOS 32bit call
569  *	@_call: pointer to struct apm_bios_call.
570  *
571  *	Make an APM call using the 32bit protected mode interface. The
572  *	caller is responsible for knowing if APM BIOS is configured and
573  *	enabled. This call can disable interrupts for a long period of
574  *	time on some laptops.  The return value is in AH and the carry
575  *	flag is loaded into AL.  If there is an error, then the error
576  *	code is returned in AH (bits 8-15 of eax) and this function
577  *	returns non-zero.
578  *
579  *	Note: this makes the call on the current CPU.
580  */
581 static long __apm_bios_call(void *_call)
582 {
583 	APM_DECL_SEGS
584 	unsigned long		flags;
585 	int			cpu;
586 	struct desc_struct	save_desc_40;
587 	struct desc_struct	*gdt;
588 	struct apm_bios_call	*call = _call;
589 
590 	cpu = get_cpu();
591 	BUG_ON(cpu != 0);
592 	gdt = get_cpu_gdt_table(cpu);
593 	save_desc_40 = gdt[0x40 / 8];
594 	gdt[0x40 / 8] = bad_bios_desc;
595 
596 	apm_irq_save(flags);
597 	APM_DO_SAVE_SEGS;
598 	apm_bios_call_asm(call->func, call->ebx, call->ecx,
599 			  &call->eax, &call->ebx, &call->ecx, &call->edx,
600 			  &call->esi);
601 	APM_DO_RESTORE_SEGS;
602 	apm_irq_restore(flags);
603 	gdt[0x40 / 8] = save_desc_40;
604 	put_cpu();
605 
606 	return call->eax & 0xff;
607 }
608 
609 /* Run __apm_bios_call or __apm_bios_call_simple on CPU 0 */
610 static int on_cpu0(long (*fn)(void *), struct apm_bios_call *call)
611 {
612 	int ret;
613 
614 	/* Don't bother with work_on_cpu in the common case, so we don't
615 	 * have to worry about OOM or overhead. */
616 	if (get_cpu() == 0) {
617 		ret = fn(call);
618 		put_cpu();
619 	} else {
620 		put_cpu();
621 		ret = work_on_cpu(0, fn, call);
622 	}
623 
624 	/* work_on_cpu can fail with -ENOMEM */
625 	if (ret < 0)
626 		call->err = ret;
627 	else
628 		call->err = (call->eax >> 8) & 0xff;
629 
630 	return ret;
631 }
632 
633 /**
634  *	apm_bios_call	-	Make an APM BIOS 32bit call (on CPU 0)
635  *	@call: the apm_bios_call registers.
636  *
637  *	If there is an error, it is returned in @call.err.
638  */
639 static int apm_bios_call(struct apm_bios_call *call)
640 {
641 	return on_cpu0(__apm_bios_call, call);
642 }
643 
644 /**
645  *	__apm_bios_call_simple - Make an APM BIOS 32bit call (on CPU 0)
646  *	@_call: pointer to struct apm_bios_call.
647  *
648  *	Make a BIOS call that returns one value only, or just status.
649  *	If there is an error, then the error code is returned in AH
650  *	(bits 8-15 of eax) and this function returns non-zero (it can
651  *	also return -ENOMEM). This is used for simpler BIOS operations.
652  *	This call may hold interrupts off for a long time on some laptops.
653  *
654  *	Note: this makes the call on the current CPU.
655  */
656 static long __apm_bios_call_simple(void *_call)
657 {
658 	u8			error;
659 	APM_DECL_SEGS
660 	unsigned long		flags;
661 	int			cpu;
662 	struct desc_struct	save_desc_40;
663 	struct desc_struct	*gdt;
664 	struct apm_bios_call	*call = _call;
665 
666 	cpu = get_cpu();
667 	BUG_ON(cpu != 0);
668 	gdt = get_cpu_gdt_table(cpu);
669 	save_desc_40 = gdt[0x40 / 8];
670 	gdt[0x40 / 8] = bad_bios_desc;
671 
672 	apm_irq_save(flags);
673 	APM_DO_SAVE_SEGS;
674 	error = apm_bios_call_simple_asm(call->func, call->ebx, call->ecx,
675 					 &call->eax);
676 	APM_DO_RESTORE_SEGS;
677 	apm_irq_restore(flags);
678 	gdt[0x40 / 8] = save_desc_40;
679 	put_cpu();
680 	return error;
681 }
682 
683 /**
684  *	apm_bios_call_simple	-	make a simple APM BIOS 32bit call
685  *	@func: APM function to invoke
686  *	@ebx_in: EBX register value for BIOS call
687  *	@ecx_in: ECX register value for BIOS call
688  *	@eax: EAX register on return from the BIOS call
689  *	@err: bits
690  *
691  *	Make a BIOS call that returns one value only, or just status.
692  *	If there is an error, then the error code is returned in @err
693  *	and this function returns non-zero. This is used for simpler
694  *	BIOS operations.  This call may hold interrupts off for a long
695  *	time on some laptops.
696  */
697 static int apm_bios_call_simple(u32 func, u32 ebx_in, u32 ecx_in, u32 *eax,
698 				int *err)
699 {
700 	struct apm_bios_call call;
701 	int ret;
702 
703 	call.func = func;
704 	call.ebx = ebx_in;
705 	call.ecx = ecx_in;
706 
707 	ret = on_cpu0(__apm_bios_call_simple, &call);
708 	*eax = call.eax;
709 	*err = call.err;
710 	return ret;
711 }
712 
713 /**
714  *	apm_driver_version	-	APM driver version
715  *	@val:	loaded with the APM version on return
716  *
717  *	Retrieve the APM version supported by the BIOS. This is only
718  *	supported for APM 1.1 or higher. An error indicates APM 1.0 is
719  *	probably present.
720  *
721  *	On entry val should point to a value indicating the APM driver
722  *	version with the high byte being the major and the low byte the
723  *	minor number both in BCD
724  *
725  *	On return it will hold the BIOS revision supported in the
726  *	same format.
727  */
728 
729 static int apm_driver_version(u_short *val)
730 {
731 	u32 eax;
732 	int err;
733 
734 	if (apm_bios_call_simple(APM_FUNC_VERSION, 0, *val, &eax, &err))
735 		return err;
736 	*val = eax;
737 	return APM_SUCCESS;
738 }
739 
740 /**
741  *	apm_get_event	-	get an APM event from the BIOS
742  *	@event: pointer to the event
743  *	@info: point to the event information
744  *
745  *	The APM BIOS provides a polled information for event
746  *	reporting. The BIOS expects to be polled at least every second
747  *	when events are pending. When a message is found the caller should
748  *	poll until no more messages are present.  However, this causes
749  *	problems on some laptops where a suspend event notification is
750  *	not cleared until it is acknowledged.
751  *
752  *	Additional information is returned in the info pointer, providing
753  *	that APM 1.2 is in use. If no messges are pending the value 0x80
754  *	is returned (No power management events pending).
755  */
756 static int apm_get_event(apm_event_t *event, apm_eventinfo_t *info)
757 {
758 	struct apm_bios_call call;
759 
760 	call.func = APM_FUNC_GET_EVENT;
761 	call.ebx = call.ecx = 0;
762 
763 	if (apm_bios_call(&call))
764 		return call.err;
765 
766 	*event = call.ebx;
767 	if (apm_info.connection_version < 0x0102)
768 		*info = ~0; /* indicate info not valid */
769 	else
770 		*info = call.ecx;
771 	return APM_SUCCESS;
772 }
773 
774 /**
775  *	set_power_state	-	set the power management state
776  *	@what: which items to transition
777  *	@state: state to transition to
778  *
779  *	Request an APM change of state for one or more system devices. The
780  *	processor state must be transitioned last of all. what holds the
781  *	class of device in the upper byte and the device number (0xFF for
782  *	all) for the object to be transitioned.
783  *
784  *	The state holds the state to transition to, which may in fact
785  *	be an acceptance of a BIOS requested state change.
786  */
787 
788 static int set_power_state(u_short what, u_short state)
789 {
790 	u32 eax;
791 	int err;
792 
793 	if (apm_bios_call_simple(APM_FUNC_SET_STATE, what, state, &eax, &err))
794 		return err;
795 	return APM_SUCCESS;
796 }
797 
798 /**
799  *	set_system_power_state - set system wide power state
800  *	@state: which state to enter
801  *
802  *	Transition the entire system into a new APM power state.
803  */
804 
805 static int set_system_power_state(u_short state)
806 {
807 	return set_power_state(APM_DEVICE_ALL, state);
808 }
809 
810 /**
811  *	apm_do_idle	-	perform power saving
812  *
813  *	This function notifies the BIOS that the processor is (in the view
814  *	of the OS) idle. It returns -1 in the event that the BIOS refuses
815  *	to handle the idle request. On a success the function returns 1
816  *	if the BIOS did clock slowing or 0 otherwise.
817  */
818 
819 static int apm_do_idle(void)
820 {
821 	u32 eax;
822 	u8 ret = 0;
823 	int idled = 0;
824 	int polling;
825 	int err = 0;
826 
827 	polling = !!(current_thread_info()->status & TS_POLLING);
828 	if (polling) {
829 		current_thread_info()->status &= ~TS_POLLING;
830 		/*
831 		 * TS_POLLING-cleared state must be visible before we
832 		 * test NEED_RESCHED:
833 		 */
834 		smp_mb();
835 	}
836 	if (!need_resched()) {
837 		idled = 1;
838 		ret = apm_bios_call_simple(APM_FUNC_IDLE, 0, 0, &eax, &err);
839 	}
840 	if (polling)
841 		current_thread_info()->status |= TS_POLLING;
842 
843 	if (!idled)
844 		return 0;
845 
846 	if (ret) {
847 		static unsigned long t;
848 
849 		/* This always fails on some SMP boards running UP kernels.
850 		 * Only report the failure the first 5 times.
851 		 */
852 		if (++t < 5) {
853 			printk(KERN_DEBUG "apm_do_idle failed (%d)\n", err);
854 			t = jiffies;
855 		}
856 		return -1;
857 	}
858 	clock_slowed = (apm_info.bios.flags & APM_IDLE_SLOWS_CLOCK) != 0;
859 	return clock_slowed;
860 }
861 
862 /**
863  *	apm_do_busy	-	inform the BIOS the CPU is busy
864  *
865  *	Request that the BIOS brings the CPU back to full performance.
866  */
867 
868 static void apm_do_busy(void)
869 {
870 	u32 dummy;
871 	int err;
872 
873 	if (clock_slowed || ALWAYS_CALL_BUSY) {
874 		(void)apm_bios_call_simple(APM_FUNC_BUSY, 0, 0, &dummy, &err);
875 		clock_slowed = 0;
876 	}
877 }
878 
879 /*
880  * If no process has really been interested in
881  * the CPU for some time, we want to call BIOS
882  * power management - we probably want
883  * to conserve power.
884  */
885 #define IDLE_CALC_LIMIT	(HZ * 100)
886 #define IDLE_LEAKY_MAX	16
887 
888 static void (*original_pm_idle)(void) __read_mostly;
889 
890 /**
891  * apm_cpu_idle		-	cpu idling for APM capable Linux
892  *
893  * This is the idling function the kernel executes when APM is available. It
894  * tries to do BIOS powermanagement based on the average system idle time.
895  * Furthermore it calls the system default idle routine.
896  */
897 
898 static void apm_cpu_idle(void)
899 {
900 	static int use_apm_idle; /* = 0 */
901 	static unsigned int last_jiffies; /* = 0 */
902 	static unsigned int last_stime; /* = 0 */
903 
904 	int apm_idle_done = 0;
905 	unsigned int jiffies_since_last_check = jiffies - last_jiffies;
906 	unsigned int bucket;
907 
908 	WARN_ONCE(1, "deprecated apm_cpu_idle will be deleted in 2012");
909 recalc:
910 	if (jiffies_since_last_check > IDLE_CALC_LIMIT) {
911 		use_apm_idle = 0;
912 		last_jiffies = jiffies;
913 		last_stime = current->stime;
914 	} else if (jiffies_since_last_check > idle_period) {
915 		unsigned int idle_percentage;
916 
917 		idle_percentage = current->stime - last_stime;
918 		idle_percentage *= 100;
919 		idle_percentage /= jiffies_since_last_check;
920 		use_apm_idle = (idle_percentage > idle_threshold);
921 		if (apm_info.forbid_idle)
922 			use_apm_idle = 0;
923 		last_jiffies = jiffies;
924 		last_stime = current->stime;
925 	}
926 
927 	bucket = IDLE_LEAKY_MAX;
928 
929 	while (!need_resched()) {
930 		if (use_apm_idle) {
931 			unsigned int t;
932 
933 			t = jiffies;
934 			switch (apm_do_idle()) {
935 			case 0:
936 				apm_idle_done = 1;
937 				if (t != jiffies) {
938 					if (bucket) {
939 						bucket = IDLE_LEAKY_MAX;
940 						continue;
941 					}
942 				} else if (bucket) {
943 					bucket--;
944 					continue;
945 				}
946 				break;
947 			case 1:
948 				apm_idle_done = 1;
949 				break;
950 			default: /* BIOS refused */
951 				break;
952 			}
953 		}
954 		if (original_pm_idle)
955 			original_pm_idle();
956 		else
957 			default_idle();
958 		local_irq_disable();
959 		jiffies_since_last_check = jiffies - last_jiffies;
960 		if (jiffies_since_last_check > idle_period)
961 			goto recalc;
962 	}
963 
964 	if (apm_idle_done)
965 		apm_do_busy();
966 
967 	local_irq_enable();
968 }
969 
970 /**
971  *	apm_power_off	-	ask the BIOS to power off
972  *
973  *	Handle the power off sequence. This is the one piece of code we
974  *	will execute even on SMP machines. In order to deal with BIOS
975  *	bugs we support real mode APM BIOS power off calls. We also make
976  *	the SMP call on CPU0 as some systems will only honour this call
977  *	on their first cpu.
978  */
979 
980 static void apm_power_off(void)
981 {
982 	/* Some bioses don't like being called from CPU != 0 */
983 	if (apm_info.realmode_power_off) {
984 		set_cpus_allowed_ptr(current, cpumask_of(0));
985 		machine_real_restart(MRR_APM);
986 	} else {
987 		(void)set_system_power_state(APM_STATE_OFF);
988 	}
989 }
990 
991 #ifdef CONFIG_APM_DO_ENABLE
992 
993 /**
994  *	apm_enable_power_management - enable BIOS APM power management
995  *	@enable: enable yes/no
996  *
997  *	Enable or disable the APM BIOS power services.
998  */
999 
1000 static int apm_enable_power_management(int enable)
1001 {
1002 	u32 eax;
1003 	int err;
1004 
1005 	if ((enable == 0) && (apm_info.bios.flags & APM_BIOS_DISENGAGED))
1006 		return APM_NOT_ENGAGED;
1007 	if (apm_bios_call_simple(APM_FUNC_ENABLE_PM, APM_DEVICE_BALL,
1008 				 enable, &eax, &err))
1009 		return err;
1010 	if (enable)
1011 		apm_info.bios.flags &= ~APM_BIOS_DISABLED;
1012 	else
1013 		apm_info.bios.flags |= APM_BIOS_DISABLED;
1014 	return APM_SUCCESS;
1015 }
1016 #endif
1017 
1018 /**
1019  *	apm_get_power_status	-	get current power state
1020  *	@status: returned status
1021  *	@bat: battery info
1022  *	@life: estimated life
1023  *
1024  *	Obtain the current power status from the APM BIOS. We return a
1025  *	status which gives the rough battery status, and current power
1026  *	source. The bat value returned give an estimate as a percentage
1027  *	of life and a status value for the battery. The estimated life
1028  *	if reported is a lifetime in secodnds/minutes at current powwer
1029  *	consumption.
1030  */
1031 
1032 static int apm_get_power_status(u_short *status, u_short *bat, u_short *life)
1033 {
1034 	struct apm_bios_call call;
1035 
1036 	call.func = APM_FUNC_GET_STATUS;
1037 	call.ebx = APM_DEVICE_ALL;
1038 	call.ecx = 0;
1039 
1040 	if (apm_info.get_power_status_broken)
1041 		return APM_32_UNSUPPORTED;
1042 	if (apm_bios_call(&call))
1043 		return call.err;
1044 	*status = call.ebx;
1045 	*bat = call.ecx;
1046 	if (apm_info.get_power_status_swabinminutes) {
1047 		*life = swab16((u16)call.edx);
1048 		*life |= 0x8000;
1049 	} else
1050 		*life = call.edx;
1051 	return APM_SUCCESS;
1052 }
1053 
1054 #if 0
1055 static int apm_get_battery_status(u_short which, u_short *status,
1056 				  u_short *bat, u_short *life, u_short *nbat)
1057 {
1058 	u32 eax;
1059 	u32 ebx;
1060 	u32 ecx;
1061 	u32 edx;
1062 	u32 esi;
1063 
1064 	if (apm_info.connection_version < 0x0102) {
1065 		/* pretend we only have one battery. */
1066 		if (which != 1)
1067 			return APM_BAD_DEVICE;
1068 		*nbat = 1;
1069 		return apm_get_power_status(status, bat, life);
1070 	}
1071 
1072 	if (apm_bios_call(APM_FUNC_GET_STATUS, (0x8000 | (which)), 0, &eax,
1073 			  &ebx, &ecx, &edx, &esi))
1074 		return (eax >> 8) & 0xff;
1075 	*status = ebx;
1076 	*bat = ecx;
1077 	*life = edx;
1078 	*nbat = esi;
1079 	return APM_SUCCESS;
1080 }
1081 #endif
1082 
1083 /**
1084  *	apm_engage_power_management	-	enable PM on a device
1085  *	@device: identity of device
1086  *	@enable: on/off
1087  *
1088  *	Activate or deactive power management on either a specific device
1089  *	or the entire system (%APM_DEVICE_ALL).
1090  */
1091 
1092 static int apm_engage_power_management(u_short device, int enable)
1093 {
1094 	u32 eax;
1095 	int err;
1096 
1097 	if ((enable == 0) && (device == APM_DEVICE_ALL)
1098 	    && (apm_info.bios.flags & APM_BIOS_DISABLED))
1099 		return APM_DISABLED;
1100 	if (apm_bios_call_simple(APM_FUNC_ENGAGE_PM, device, enable,
1101 				 &eax, &err))
1102 		return err;
1103 	if (device == APM_DEVICE_ALL) {
1104 		if (enable)
1105 			apm_info.bios.flags &= ~APM_BIOS_DISENGAGED;
1106 		else
1107 			apm_info.bios.flags |= APM_BIOS_DISENGAGED;
1108 	}
1109 	return APM_SUCCESS;
1110 }
1111 
1112 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1113 
1114 /**
1115  *	apm_console_blank	-	blank the display
1116  *	@blank: on/off
1117  *
1118  *	Attempt to blank the console, firstly by blanking just video device
1119  *	zero, and if that fails (some BIOSes don't support it) then it blanks
1120  *	all video devices. Typically the BIOS will do laptop backlight and
1121  *	monitor powerdown for us.
1122  */
1123 
1124 static int apm_console_blank(int blank)
1125 {
1126 	int error = APM_NOT_ENGAGED; /* silence gcc */
1127 	int i;
1128 	u_short state;
1129 	static const u_short dev[3] = { 0x100, 0x1FF, 0x101 };
1130 
1131 	state = blank ? APM_STATE_STANDBY : APM_STATE_READY;
1132 
1133 	for (i = 0; i < ARRAY_SIZE(dev); i++) {
1134 		error = set_power_state(dev[i], state);
1135 
1136 		if ((error == APM_SUCCESS) || (error == APM_NO_ERROR))
1137 			return 1;
1138 
1139 		if (error == APM_NOT_ENGAGED)
1140 			break;
1141 	}
1142 
1143 	if (error == APM_NOT_ENGAGED) {
1144 		static int tried;
1145 		int eng_error;
1146 		if (tried++ == 0) {
1147 			eng_error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1148 			if (eng_error) {
1149 				apm_error("set display", error);
1150 				apm_error("engage interface", eng_error);
1151 				return 0;
1152 			} else
1153 				return apm_console_blank(blank);
1154 		}
1155 	}
1156 	apm_error("set display", error);
1157 	return 0;
1158 }
1159 #endif
1160 
1161 static int queue_empty(struct apm_user *as)
1162 {
1163 	return as->event_head == as->event_tail;
1164 }
1165 
1166 static apm_event_t get_queued_event(struct apm_user *as)
1167 {
1168 	if (++as->event_tail >= APM_MAX_EVENTS)
1169 		as->event_tail = 0;
1170 	return as->events[as->event_tail];
1171 }
1172 
1173 static void queue_event(apm_event_t event, struct apm_user *sender)
1174 {
1175 	struct apm_user *as;
1176 
1177 	spin_lock(&user_list_lock);
1178 	if (user_list == NULL)
1179 		goto out;
1180 	for (as = user_list; as != NULL; as = as->next) {
1181 		if ((as == sender) || (!as->reader))
1182 			continue;
1183 		if (++as->event_head >= APM_MAX_EVENTS)
1184 			as->event_head = 0;
1185 
1186 		if (as->event_head == as->event_tail) {
1187 			static int notified;
1188 
1189 			if (notified++ == 0)
1190 			    printk(KERN_ERR "apm: an event queue overflowed\n");
1191 			if (++as->event_tail >= APM_MAX_EVENTS)
1192 				as->event_tail = 0;
1193 		}
1194 		as->events[as->event_head] = event;
1195 		if (!as->suser || !as->writer)
1196 			continue;
1197 		switch (event) {
1198 		case APM_SYS_SUSPEND:
1199 		case APM_USER_SUSPEND:
1200 			as->suspends_pending++;
1201 			suspends_pending++;
1202 			break;
1203 
1204 		case APM_SYS_STANDBY:
1205 		case APM_USER_STANDBY:
1206 			as->standbys_pending++;
1207 			standbys_pending++;
1208 			break;
1209 		}
1210 	}
1211 	wake_up_interruptible(&apm_waitqueue);
1212 out:
1213 	spin_unlock(&user_list_lock);
1214 }
1215 
1216 static void reinit_timer(void)
1217 {
1218 #ifdef INIT_TIMER_AFTER_SUSPEND
1219 	unsigned long flags;
1220 
1221 	raw_spin_lock_irqsave(&i8253_lock, flags);
1222 	/* set the clock to HZ */
1223 	outb_pit(0x34, PIT_MODE);		/* binary, mode 2, LSB/MSB, ch 0 */
1224 	udelay(10);
1225 	outb_pit(LATCH & 0xff, PIT_CH0);	/* LSB */
1226 	udelay(10);
1227 	outb_pit(LATCH >> 8, PIT_CH0);	/* MSB */
1228 	udelay(10);
1229 	raw_spin_unlock_irqrestore(&i8253_lock, flags);
1230 #endif
1231 }
1232 
1233 static int suspend(int vetoable)
1234 {
1235 	int err;
1236 	struct apm_user	*as;
1237 
1238 	dpm_suspend_start(PMSG_SUSPEND);
1239 
1240 	dpm_suspend_noirq(PMSG_SUSPEND);
1241 
1242 	local_irq_disable();
1243 	syscore_suspend();
1244 
1245 	local_irq_enable();
1246 
1247 	save_processor_state();
1248 	err = set_system_power_state(APM_STATE_SUSPEND);
1249 	ignore_normal_resume = 1;
1250 	restore_processor_state();
1251 
1252 	local_irq_disable();
1253 	reinit_timer();
1254 
1255 	if (err == APM_NO_ERROR)
1256 		err = APM_SUCCESS;
1257 	if (err != APM_SUCCESS)
1258 		apm_error("suspend", err);
1259 	err = (err == APM_SUCCESS) ? 0 : -EIO;
1260 
1261 	syscore_resume();
1262 	local_irq_enable();
1263 
1264 	dpm_resume_noirq(PMSG_RESUME);
1265 
1266 	dpm_resume_end(PMSG_RESUME);
1267 	queue_event(APM_NORMAL_RESUME, NULL);
1268 	spin_lock(&user_list_lock);
1269 	for (as = user_list; as != NULL; as = as->next) {
1270 		as->suspend_wait = 0;
1271 		as->suspend_result = err;
1272 	}
1273 	spin_unlock(&user_list_lock);
1274 	wake_up_interruptible(&apm_suspend_waitqueue);
1275 	return err;
1276 }
1277 
1278 static void standby(void)
1279 {
1280 	int err;
1281 
1282 	dpm_suspend_noirq(PMSG_SUSPEND);
1283 
1284 	local_irq_disable();
1285 	syscore_suspend();
1286 	local_irq_enable();
1287 
1288 	err = set_system_power_state(APM_STATE_STANDBY);
1289 	if ((err != APM_SUCCESS) && (err != APM_NO_ERROR))
1290 		apm_error("standby", err);
1291 
1292 	local_irq_disable();
1293 	syscore_resume();
1294 	local_irq_enable();
1295 
1296 	dpm_resume_noirq(PMSG_RESUME);
1297 }
1298 
1299 static apm_event_t get_event(void)
1300 {
1301 	int error;
1302 	apm_event_t event = APM_NO_EVENTS; /* silence gcc */
1303 	apm_eventinfo_t	info;
1304 
1305 	static int notified;
1306 
1307 	/* we don't use the eventinfo */
1308 	error = apm_get_event(&event, &info);
1309 	if (error == APM_SUCCESS)
1310 		return event;
1311 
1312 	if ((error != APM_NO_EVENTS) && (notified++ == 0))
1313 		apm_error("get_event", error);
1314 
1315 	return 0;
1316 }
1317 
1318 static void check_events(void)
1319 {
1320 	apm_event_t event;
1321 	static unsigned long last_resume;
1322 	static int ignore_bounce;
1323 
1324 	while ((event = get_event()) != 0) {
1325 		if (debug) {
1326 			if (event <= NR_APM_EVENT_NAME)
1327 				printk(KERN_DEBUG "apm: received %s notify\n",
1328 				       apm_event_name[event - 1]);
1329 			else
1330 				printk(KERN_DEBUG "apm: received unknown "
1331 				       "event 0x%02x\n", event);
1332 		}
1333 		if (ignore_bounce
1334 		    && (time_after(jiffies, last_resume + bounce_interval)))
1335 			ignore_bounce = 0;
1336 
1337 		switch (event) {
1338 		case APM_SYS_STANDBY:
1339 		case APM_USER_STANDBY:
1340 			queue_event(event, NULL);
1341 			if (standbys_pending <= 0)
1342 				standby();
1343 			break;
1344 
1345 		case APM_USER_SUSPEND:
1346 #ifdef CONFIG_APM_IGNORE_USER_SUSPEND
1347 			if (apm_info.connection_version > 0x100)
1348 				set_system_power_state(APM_STATE_REJECT);
1349 			break;
1350 #endif
1351 		case APM_SYS_SUSPEND:
1352 			if (ignore_bounce) {
1353 				if (apm_info.connection_version > 0x100)
1354 					set_system_power_state(APM_STATE_REJECT);
1355 				break;
1356 			}
1357 			/*
1358 			 * If we are already processing a SUSPEND,
1359 			 * then further SUSPEND events from the BIOS
1360 			 * will be ignored.  We also return here to
1361 			 * cope with the fact that the Thinkpads keep
1362 			 * sending a SUSPEND event until something else
1363 			 * happens!
1364 			 */
1365 			if (ignore_sys_suspend)
1366 				return;
1367 			ignore_sys_suspend = 1;
1368 			queue_event(event, NULL);
1369 			if (suspends_pending <= 0)
1370 				(void) suspend(1);
1371 			break;
1372 
1373 		case APM_NORMAL_RESUME:
1374 		case APM_CRITICAL_RESUME:
1375 		case APM_STANDBY_RESUME:
1376 			ignore_sys_suspend = 0;
1377 			last_resume = jiffies;
1378 			ignore_bounce = 1;
1379 			if ((event != APM_NORMAL_RESUME)
1380 			    || (ignore_normal_resume == 0)) {
1381 				dpm_resume_end(PMSG_RESUME);
1382 				queue_event(event, NULL);
1383 			}
1384 			ignore_normal_resume = 0;
1385 			break;
1386 
1387 		case APM_CAPABILITY_CHANGE:
1388 		case APM_LOW_BATTERY:
1389 		case APM_POWER_STATUS_CHANGE:
1390 			queue_event(event, NULL);
1391 			/* If needed, notify drivers here */
1392 			break;
1393 
1394 		case APM_UPDATE_TIME:
1395 			break;
1396 
1397 		case APM_CRITICAL_SUSPEND:
1398 			/*
1399 			 * We are not allowed to reject a critical suspend.
1400 			 */
1401 			(void)suspend(0);
1402 			break;
1403 		}
1404 	}
1405 }
1406 
1407 static void apm_event_handler(void)
1408 {
1409 	static int pending_count = 4;
1410 	int err;
1411 
1412 	if ((standbys_pending > 0) || (suspends_pending > 0)) {
1413 		if ((apm_info.connection_version > 0x100) &&
1414 		    (pending_count-- <= 0)) {
1415 			pending_count = 4;
1416 			if (debug)
1417 				printk(KERN_DEBUG "apm: setting state busy\n");
1418 			err = set_system_power_state(APM_STATE_BUSY);
1419 			if (err)
1420 				apm_error("busy", err);
1421 		}
1422 	} else
1423 		pending_count = 4;
1424 	check_events();
1425 }
1426 
1427 /*
1428  * This is the APM thread main loop.
1429  */
1430 
1431 static void apm_mainloop(void)
1432 {
1433 	DECLARE_WAITQUEUE(wait, current);
1434 
1435 	add_wait_queue(&apm_waitqueue, &wait);
1436 	set_current_state(TASK_INTERRUPTIBLE);
1437 	for (;;) {
1438 		schedule_timeout(APM_CHECK_TIMEOUT);
1439 		if (kthread_should_stop())
1440 			break;
1441 		/*
1442 		 * Ok, check all events, check for idle (and mark us sleeping
1443 		 * so as not to count towards the load average)..
1444 		 */
1445 		set_current_state(TASK_INTERRUPTIBLE);
1446 		apm_event_handler();
1447 	}
1448 	remove_wait_queue(&apm_waitqueue, &wait);
1449 }
1450 
1451 static int check_apm_user(struct apm_user *as, const char *func)
1452 {
1453 	if (as == NULL || as->magic != APM_BIOS_MAGIC) {
1454 		printk(KERN_ERR "apm: %s passed bad filp\n", func);
1455 		return 1;
1456 	}
1457 	return 0;
1458 }
1459 
1460 static ssize_t do_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
1461 {
1462 	struct apm_user *as;
1463 	int i;
1464 	apm_event_t event;
1465 
1466 	as = fp->private_data;
1467 	if (check_apm_user(as, "read"))
1468 		return -EIO;
1469 	if ((int)count < sizeof(apm_event_t))
1470 		return -EINVAL;
1471 	if ((queue_empty(as)) && (fp->f_flags & O_NONBLOCK))
1472 		return -EAGAIN;
1473 	wait_event_interruptible(apm_waitqueue, !queue_empty(as));
1474 	i = count;
1475 	while ((i >= sizeof(event)) && !queue_empty(as)) {
1476 		event = get_queued_event(as);
1477 		if (copy_to_user(buf, &event, sizeof(event))) {
1478 			if (i < count)
1479 				break;
1480 			return -EFAULT;
1481 		}
1482 		switch (event) {
1483 		case APM_SYS_SUSPEND:
1484 		case APM_USER_SUSPEND:
1485 			as->suspends_read++;
1486 			break;
1487 
1488 		case APM_SYS_STANDBY:
1489 		case APM_USER_STANDBY:
1490 			as->standbys_read++;
1491 			break;
1492 		}
1493 		buf += sizeof(event);
1494 		i -= sizeof(event);
1495 	}
1496 	if (i < count)
1497 		return count - i;
1498 	if (signal_pending(current))
1499 		return -ERESTARTSYS;
1500 	return 0;
1501 }
1502 
1503 static unsigned int do_poll(struct file *fp, poll_table *wait)
1504 {
1505 	struct apm_user *as;
1506 
1507 	as = fp->private_data;
1508 	if (check_apm_user(as, "poll"))
1509 		return 0;
1510 	poll_wait(fp, &apm_waitqueue, wait);
1511 	if (!queue_empty(as))
1512 		return POLLIN | POLLRDNORM;
1513 	return 0;
1514 }
1515 
1516 static long do_ioctl(struct file *filp, u_int cmd, u_long arg)
1517 {
1518 	struct apm_user *as;
1519 	int ret;
1520 
1521 	as = filp->private_data;
1522 	if (check_apm_user(as, "ioctl"))
1523 		return -EIO;
1524 	if (!as->suser || !as->writer)
1525 		return -EPERM;
1526 	switch (cmd) {
1527 	case APM_IOC_STANDBY:
1528 		mutex_lock(&apm_mutex);
1529 		if (as->standbys_read > 0) {
1530 			as->standbys_read--;
1531 			as->standbys_pending--;
1532 			standbys_pending--;
1533 		} else
1534 			queue_event(APM_USER_STANDBY, as);
1535 		if (standbys_pending <= 0)
1536 			standby();
1537 		mutex_unlock(&apm_mutex);
1538 		break;
1539 	case APM_IOC_SUSPEND:
1540 		mutex_lock(&apm_mutex);
1541 		if (as->suspends_read > 0) {
1542 			as->suspends_read--;
1543 			as->suspends_pending--;
1544 			suspends_pending--;
1545 		} else
1546 			queue_event(APM_USER_SUSPEND, as);
1547 		if (suspends_pending <= 0) {
1548 			ret = suspend(1);
1549 			mutex_unlock(&apm_mutex);
1550 		} else {
1551 			as->suspend_wait = 1;
1552 			mutex_unlock(&apm_mutex);
1553 			wait_event_interruptible(apm_suspend_waitqueue,
1554 					as->suspend_wait == 0);
1555 			ret = as->suspend_result;
1556 		}
1557 		return ret;
1558 	default:
1559 		return -ENOTTY;
1560 	}
1561 	return 0;
1562 }
1563 
1564 static int do_release(struct inode *inode, struct file *filp)
1565 {
1566 	struct apm_user *as;
1567 
1568 	as = filp->private_data;
1569 	if (check_apm_user(as, "release"))
1570 		return 0;
1571 	filp->private_data = NULL;
1572 	if (as->standbys_pending > 0) {
1573 		standbys_pending -= as->standbys_pending;
1574 		if (standbys_pending <= 0)
1575 			standby();
1576 	}
1577 	if (as->suspends_pending > 0) {
1578 		suspends_pending -= as->suspends_pending;
1579 		if (suspends_pending <= 0)
1580 			(void) suspend(1);
1581 	}
1582 	spin_lock(&user_list_lock);
1583 	if (user_list == as)
1584 		user_list = as->next;
1585 	else {
1586 		struct apm_user *as1;
1587 
1588 		for (as1 = user_list;
1589 		     (as1 != NULL) && (as1->next != as);
1590 		     as1 = as1->next)
1591 			;
1592 		if (as1 == NULL)
1593 			printk(KERN_ERR "apm: filp not in user list\n");
1594 		else
1595 			as1->next = as->next;
1596 	}
1597 	spin_unlock(&user_list_lock);
1598 	kfree(as);
1599 	return 0;
1600 }
1601 
1602 static int do_open(struct inode *inode, struct file *filp)
1603 {
1604 	struct apm_user *as;
1605 
1606 	as = kmalloc(sizeof(*as), GFP_KERNEL);
1607 	if (as == NULL) {
1608 		printk(KERN_ERR "apm: cannot allocate struct of size %d bytes\n",
1609 		       sizeof(*as));
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 || paravirt_enabled() || 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 		printk(KERN_NOTICE "apm: disabled on user request.\n");
2321 		return -ENODEV;
2322 	}
2323 	if ((num_online_cpus() > 1) && !power_off && !smp) {
2324 		printk(KERN_NOTICE "apm: disabled - APM is not SMP safe.\n");
2325 		apm_info.disabled = 1;
2326 		return -ENODEV;
2327 	}
2328 	if (!acpi_disabled) {
2329 		printk(KERN_NOTICE "apm: 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 		printk(KERN_ERR "apm: disabled - Unable to start kernel "
2364 				"thread.\n");
2365 		err = PTR_ERR(kapmd_task);
2366 		kapmd_task = NULL;
2367 		remove_proc_entry("apm", NULL);
2368 		return err;
2369 	}
2370 	wake_up_process(kapmd_task);
2371 
2372 	if (num_online_cpus() > 1 && !smp) {
2373 		printk(KERN_NOTICE
2374 		       "apm: disabled - APM is not SMP safe (power off active).\n");
2375 		return 0;
2376 	}
2377 
2378 	/*
2379 	 * Note we don't actually care if the misc_device cannot be registered.
2380 	 * this driver can do its job without it, even if userspace can't
2381 	 * control it.  just log the error
2382 	 */
2383 	if (misc_register(&apm_device))
2384 		printk(KERN_WARNING "apm: Could not register misc device.\n");
2385 
2386 	if (HZ != 100)
2387 		idle_period = (idle_period * HZ) / 100;
2388 	if (idle_threshold < 100) {
2389 		original_pm_idle = pm_idle;
2390 		pm_idle  = apm_cpu_idle;
2391 		set_pm_idle = 1;
2392 	}
2393 
2394 	return 0;
2395 }
2396 
2397 static void __exit apm_exit(void)
2398 {
2399 	int error;
2400 
2401 	if (set_pm_idle) {
2402 		pm_idle = original_pm_idle;
2403 		/*
2404 		 * We are about to unload the current idle thread pm callback
2405 		 * (pm_idle), Wait for all processors to update cached/local
2406 		 * copies of pm_idle before proceeding.
2407 		 */
2408 		cpu_idle_wait();
2409 	}
2410 	if (((apm_info.bios.flags & APM_BIOS_DISENGAGED) == 0)
2411 	    && (apm_info.connection_version > 0x0100)) {
2412 		error = apm_engage_power_management(APM_DEVICE_ALL, 0);
2413 		if (error)
2414 			apm_error("disengage power management", error);
2415 	}
2416 	misc_deregister(&apm_device);
2417 	remove_proc_entry("apm", NULL);
2418 	if (power_off)
2419 		pm_power_off = NULL;
2420 	if (kapmd_task) {
2421 		kthread_stop(kapmd_task);
2422 		kapmd_task = NULL;
2423 	}
2424 }
2425 
2426 module_init(apm_init);
2427 module_exit(apm_exit);
2428 
2429 MODULE_AUTHOR("Stephen Rothwell");
2430 MODULE_DESCRIPTION("Advanced Power Management");
2431 MODULE_LICENSE("GPL");
2432 module_param(debug, bool, 0644);
2433 MODULE_PARM_DESC(debug, "Enable debug mode");
2434 module_param(power_off, bool, 0444);
2435 MODULE_PARM_DESC(power_off, "Enable power off");
2436 module_param(bounce_interval, int, 0444);
2437 MODULE_PARM_DESC(bounce_interval,
2438 		"Set the number of ticks to ignore suspend bounces");
2439 module_param(allow_ints, bool, 0444);
2440 MODULE_PARM_DESC(allow_ints, "Allow interrupts during BIOS calls");
2441 module_param(broken_psr, bool, 0444);
2442 MODULE_PARM_DESC(broken_psr, "BIOS has a broken GetPowerStatus call");
2443 module_param(realmode_power_off, bool, 0444);
2444 MODULE_PARM_DESC(realmode_power_off,
2445 		"Switch to real mode before powering off");
2446 module_param(idle_threshold, int, 0444);
2447 MODULE_PARM_DESC(idle_threshold,
2448 	"System idle percentage above which to make APM BIOS idle calls");
2449 module_param(idle_period, int, 0444);
2450 MODULE_PARM_DESC(idle_period,
2451 	"Period (in sec/100) over which to caculate the idle percentage");
2452 module_param(smp, bool, 0444);
2453 MODULE_PARM_DESC(smp,
2454 	"Set this to enable APM use on an SMP platform. Use with caution on older systems");
2455 MODULE_ALIAS_MISCDEV(APM_MINOR_DEV);
2456