xref: /openbmc/linux/arch/x86/kernel/apm_32.c (revision 8bc55f80)
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