xref: /openbmc/linux/arch/x86/kernel/apm_32.c (revision 8730046c)
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 <linux/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, utime;
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, &utime, &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 		if (!call.err)
1047 			return APM_NO_ERROR;
1048 		return call.err;
1049 	}
1050 	*status = call.ebx;
1051 	*bat = call.ecx;
1052 	if (apm_info.get_power_status_swabinminutes) {
1053 		*life = swab16((u16)call.edx);
1054 		*life |= 0x8000;
1055 	} else
1056 		*life = call.edx;
1057 	return APM_SUCCESS;
1058 }
1059 
1060 #if 0
1061 static int apm_get_battery_status(u_short which, u_short *status,
1062 				  u_short *bat, u_short *life, u_short *nbat)
1063 {
1064 	u32 eax;
1065 	u32 ebx;
1066 	u32 ecx;
1067 	u32 edx;
1068 	u32 esi;
1069 
1070 	if (apm_info.connection_version < 0x0102) {
1071 		/* pretend we only have one battery. */
1072 		if (which != 1)
1073 			return APM_BAD_DEVICE;
1074 		*nbat = 1;
1075 		return apm_get_power_status(status, bat, life);
1076 	}
1077 
1078 	if (apm_bios_call(APM_FUNC_GET_STATUS, (0x8000 | (which)), 0, &eax,
1079 			  &ebx, &ecx, &edx, &esi))
1080 		return (eax >> 8) & 0xff;
1081 	*status = ebx;
1082 	*bat = ecx;
1083 	*life = edx;
1084 	*nbat = esi;
1085 	return APM_SUCCESS;
1086 }
1087 #endif
1088 
1089 /**
1090  *	apm_engage_power_management	-	enable PM on a device
1091  *	@device: identity of device
1092  *	@enable: on/off
1093  *
1094  *	Activate or deactivate power management on either a specific device
1095  *	or the entire system (%APM_DEVICE_ALL).
1096  */
1097 
1098 static int apm_engage_power_management(u_short device, int enable)
1099 {
1100 	u32 eax;
1101 	int err;
1102 
1103 	if ((enable == 0) && (device == APM_DEVICE_ALL)
1104 	    && (apm_info.bios.flags & APM_BIOS_DISABLED))
1105 		return APM_DISABLED;
1106 	if (apm_bios_call_simple(APM_FUNC_ENGAGE_PM, device, enable,
1107 				 &eax, &err))
1108 		return err;
1109 	if (device == APM_DEVICE_ALL) {
1110 		if (enable)
1111 			apm_info.bios.flags &= ~APM_BIOS_DISENGAGED;
1112 		else
1113 			apm_info.bios.flags |= APM_BIOS_DISENGAGED;
1114 	}
1115 	return APM_SUCCESS;
1116 }
1117 
1118 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1119 
1120 /**
1121  *	apm_console_blank	-	blank the display
1122  *	@blank: on/off
1123  *
1124  *	Attempt to blank the console, firstly by blanking just video device
1125  *	zero, and if that fails (some BIOSes don't support it) then it blanks
1126  *	all video devices. Typically the BIOS will do laptop backlight and
1127  *	monitor powerdown for us.
1128  */
1129 
1130 static int apm_console_blank(int blank)
1131 {
1132 	int error = APM_NOT_ENGAGED; /* silence gcc */
1133 	int i;
1134 	u_short state;
1135 	static const u_short dev[3] = { 0x100, 0x1FF, 0x101 };
1136 
1137 	state = blank ? APM_STATE_STANDBY : APM_STATE_READY;
1138 
1139 	for (i = 0; i < ARRAY_SIZE(dev); i++) {
1140 		error = set_power_state(dev[i], state);
1141 
1142 		if ((error == APM_SUCCESS) || (error == APM_NO_ERROR))
1143 			return 1;
1144 
1145 		if (error == APM_NOT_ENGAGED)
1146 			break;
1147 	}
1148 
1149 	if (error == APM_NOT_ENGAGED) {
1150 		static int tried;
1151 		int eng_error;
1152 		if (tried++ == 0) {
1153 			eng_error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1154 			if (eng_error) {
1155 				apm_error("set display", error);
1156 				apm_error("engage interface", eng_error);
1157 				return 0;
1158 			} else
1159 				return apm_console_blank(blank);
1160 		}
1161 	}
1162 	apm_error("set display", error);
1163 	return 0;
1164 }
1165 #endif
1166 
1167 static int queue_empty(struct apm_user *as)
1168 {
1169 	return as->event_head == as->event_tail;
1170 }
1171 
1172 static apm_event_t get_queued_event(struct apm_user *as)
1173 {
1174 	if (++as->event_tail >= APM_MAX_EVENTS)
1175 		as->event_tail = 0;
1176 	return as->events[as->event_tail];
1177 }
1178 
1179 static void queue_event(apm_event_t event, struct apm_user *sender)
1180 {
1181 	struct apm_user *as;
1182 
1183 	spin_lock(&user_list_lock);
1184 	if (user_list == NULL)
1185 		goto out;
1186 	for (as = user_list; as != NULL; as = as->next) {
1187 		if ((as == sender) || (!as->reader))
1188 			continue;
1189 		if (++as->event_head >= APM_MAX_EVENTS)
1190 			as->event_head = 0;
1191 
1192 		if (as->event_head == as->event_tail) {
1193 			static int notified;
1194 
1195 			if (notified++ == 0)
1196 				pr_err("an event queue overflowed\n");
1197 			if (++as->event_tail >= APM_MAX_EVENTS)
1198 				as->event_tail = 0;
1199 		}
1200 		as->events[as->event_head] = event;
1201 		if (!as->suser || !as->writer)
1202 			continue;
1203 		switch (event) {
1204 		case APM_SYS_SUSPEND:
1205 		case APM_USER_SUSPEND:
1206 			as->suspends_pending++;
1207 			suspends_pending++;
1208 			break;
1209 
1210 		case APM_SYS_STANDBY:
1211 		case APM_USER_STANDBY:
1212 			as->standbys_pending++;
1213 			standbys_pending++;
1214 			break;
1215 		}
1216 	}
1217 	wake_up_interruptible(&apm_waitqueue);
1218 out:
1219 	spin_unlock(&user_list_lock);
1220 }
1221 
1222 static void reinit_timer(void)
1223 {
1224 #ifdef INIT_TIMER_AFTER_SUSPEND
1225 	unsigned long flags;
1226 
1227 	raw_spin_lock_irqsave(&i8253_lock, flags);
1228 	/* set the clock to HZ */
1229 	outb_p(0x34, PIT_MODE);		/* binary, mode 2, LSB/MSB, ch 0 */
1230 	udelay(10);
1231 	outb_p(LATCH & 0xff, PIT_CH0);	/* LSB */
1232 	udelay(10);
1233 	outb_p(LATCH >> 8, PIT_CH0);	/* MSB */
1234 	udelay(10);
1235 	raw_spin_unlock_irqrestore(&i8253_lock, flags);
1236 #endif
1237 }
1238 
1239 static int suspend(int vetoable)
1240 {
1241 	int err;
1242 	struct apm_user	*as;
1243 
1244 	dpm_suspend_start(PMSG_SUSPEND);
1245 	dpm_suspend_end(PMSG_SUSPEND);
1246 
1247 	local_irq_disable();
1248 	syscore_suspend();
1249 
1250 	local_irq_enable();
1251 
1252 	save_processor_state();
1253 	err = set_system_power_state(APM_STATE_SUSPEND);
1254 	ignore_normal_resume = 1;
1255 	restore_processor_state();
1256 
1257 	local_irq_disable();
1258 	reinit_timer();
1259 
1260 	if (err == APM_NO_ERROR)
1261 		err = APM_SUCCESS;
1262 	if (err != APM_SUCCESS)
1263 		apm_error("suspend", err);
1264 	err = (err == APM_SUCCESS) ? 0 : -EIO;
1265 
1266 	syscore_resume();
1267 	local_irq_enable();
1268 
1269 	dpm_resume_start(PMSG_RESUME);
1270 	dpm_resume_end(PMSG_RESUME);
1271 
1272 	queue_event(APM_NORMAL_RESUME, NULL);
1273 	spin_lock(&user_list_lock);
1274 	for (as = user_list; as != NULL; as = as->next) {
1275 		as->suspend_wait = 0;
1276 		as->suspend_result = err;
1277 	}
1278 	spin_unlock(&user_list_lock);
1279 	wake_up_interruptible(&apm_suspend_waitqueue);
1280 	return err;
1281 }
1282 
1283 static void standby(void)
1284 {
1285 	int err;
1286 
1287 	dpm_suspend_end(PMSG_SUSPEND);
1288 
1289 	local_irq_disable();
1290 	syscore_suspend();
1291 	local_irq_enable();
1292 
1293 	err = set_system_power_state(APM_STATE_STANDBY);
1294 	if ((err != APM_SUCCESS) && (err != APM_NO_ERROR))
1295 		apm_error("standby", err);
1296 
1297 	local_irq_disable();
1298 	syscore_resume();
1299 	local_irq_enable();
1300 
1301 	dpm_resume_start(PMSG_RESUME);
1302 }
1303 
1304 static apm_event_t get_event(void)
1305 {
1306 	int error;
1307 	apm_event_t event = APM_NO_EVENTS; /* silence gcc */
1308 	apm_eventinfo_t	info;
1309 
1310 	static int notified;
1311 
1312 	/* we don't use the eventinfo */
1313 	error = apm_get_event(&event, &info);
1314 	if (error == APM_SUCCESS)
1315 		return event;
1316 
1317 	if ((error != APM_NO_EVENTS) && (notified++ == 0))
1318 		apm_error("get_event", error);
1319 
1320 	return 0;
1321 }
1322 
1323 static void check_events(void)
1324 {
1325 	apm_event_t event;
1326 	static unsigned long last_resume;
1327 	static int ignore_bounce;
1328 
1329 	while ((event = get_event()) != 0) {
1330 		if (debug) {
1331 			if (event <= NR_APM_EVENT_NAME)
1332 				printk(KERN_DEBUG "apm: received %s notify\n",
1333 				       apm_event_name[event - 1]);
1334 			else
1335 				printk(KERN_DEBUG "apm: received unknown "
1336 				       "event 0x%02x\n", event);
1337 		}
1338 		if (ignore_bounce
1339 		    && (time_after(jiffies, last_resume + bounce_interval)))
1340 			ignore_bounce = 0;
1341 
1342 		switch (event) {
1343 		case APM_SYS_STANDBY:
1344 		case APM_USER_STANDBY:
1345 			queue_event(event, NULL);
1346 			if (standbys_pending <= 0)
1347 				standby();
1348 			break;
1349 
1350 		case APM_USER_SUSPEND:
1351 #ifdef CONFIG_APM_IGNORE_USER_SUSPEND
1352 			if (apm_info.connection_version > 0x100)
1353 				set_system_power_state(APM_STATE_REJECT);
1354 			break;
1355 #endif
1356 		case APM_SYS_SUSPEND:
1357 			if (ignore_bounce) {
1358 				if (apm_info.connection_version > 0x100)
1359 					set_system_power_state(APM_STATE_REJECT);
1360 				break;
1361 			}
1362 			/*
1363 			 * If we are already processing a SUSPEND,
1364 			 * then further SUSPEND events from the BIOS
1365 			 * will be ignored.  We also return here to
1366 			 * cope with the fact that the Thinkpads keep
1367 			 * sending a SUSPEND event until something else
1368 			 * happens!
1369 			 */
1370 			if (ignore_sys_suspend)
1371 				return;
1372 			ignore_sys_suspend = 1;
1373 			queue_event(event, NULL);
1374 			if (suspends_pending <= 0)
1375 				(void) suspend(1);
1376 			break;
1377 
1378 		case APM_NORMAL_RESUME:
1379 		case APM_CRITICAL_RESUME:
1380 		case APM_STANDBY_RESUME:
1381 			ignore_sys_suspend = 0;
1382 			last_resume = jiffies;
1383 			ignore_bounce = 1;
1384 			if ((event != APM_NORMAL_RESUME)
1385 			    || (ignore_normal_resume == 0)) {
1386 				dpm_resume_end(PMSG_RESUME);
1387 				queue_event(event, NULL);
1388 			}
1389 			ignore_normal_resume = 0;
1390 			break;
1391 
1392 		case APM_CAPABILITY_CHANGE:
1393 		case APM_LOW_BATTERY:
1394 		case APM_POWER_STATUS_CHANGE:
1395 			queue_event(event, NULL);
1396 			/* If needed, notify drivers here */
1397 			break;
1398 
1399 		case APM_UPDATE_TIME:
1400 			break;
1401 
1402 		case APM_CRITICAL_SUSPEND:
1403 			/*
1404 			 * We are not allowed to reject a critical suspend.
1405 			 */
1406 			(void)suspend(0);
1407 			break;
1408 		}
1409 	}
1410 }
1411 
1412 static void apm_event_handler(void)
1413 {
1414 	static int pending_count = 4;
1415 	int err;
1416 
1417 	if ((standbys_pending > 0) || (suspends_pending > 0)) {
1418 		if ((apm_info.connection_version > 0x100) &&
1419 		    (pending_count-- <= 0)) {
1420 			pending_count = 4;
1421 			if (debug)
1422 				printk(KERN_DEBUG "apm: setting state busy\n");
1423 			err = set_system_power_state(APM_STATE_BUSY);
1424 			if (err)
1425 				apm_error("busy", err);
1426 		}
1427 	} else
1428 		pending_count = 4;
1429 	check_events();
1430 }
1431 
1432 /*
1433  * This is the APM thread main loop.
1434  */
1435 
1436 static void apm_mainloop(void)
1437 {
1438 	DECLARE_WAITQUEUE(wait, current);
1439 
1440 	add_wait_queue(&apm_waitqueue, &wait);
1441 	set_current_state(TASK_INTERRUPTIBLE);
1442 	for (;;) {
1443 		schedule_timeout(APM_CHECK_TIMEOUT);
1444 		if (kthread_should_stop())
1445 			break;
1446 		/*
1447 		 * Ok, check all events, check for idle (and mark us sleeping
1448 		 * so as not to count towards the load average)..
1449 		 */
1450 		set_current_state(TASK_INTERRUPTIBLE);
1451 		apm_event_handler();
1452 	}
1453 	remove_wait_queue(&apm_waitqueue, &wait);
1454 }
1455 
1456 static int check_apm_user(struct apm_user *as, const char *func)
1457 {
1458 	if (as == NULL || as->magic != APM_BIOS_MAGIC) {
1459 		pr_err("%s passed bad filp\n", func);
1460 		return 1;
1461 	}
1462 	return 0;
1463 }
1464 
1465 static ssize_t do_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
1466 {
1467 	struct apm_user *as;
1468 	int i;
1469 	apm_event_t event;
1470 
1471 	as = fp->private_data;
1472 	if (check_apm_user(as, "read"))
1473 		return -EIO;
1474 	if ((int)count < sizeof(apm_event_t))
1475 		return -EINVAL;
1476 	if ((queue_empty(as)) && (fp->f_flags & O_NONBLOCK))
1477 		return -EAGAIN;
1478 	wait_event_interruptible(apm_waitqueue, !queue_empty(as));
1479 	i = count;
1480 	while ((i >= sizeof(event)) && !queue_empty(as)) {
1481 		event = get_queued_event(as);
1482 		if (copy_to_user(buf, &event, sizeof(event))) {
1483 			if (i < count)
1484 				break;
1485 			return -EFAULT;
1486 		}
1487 		switch (event) {
1488 		case APM_SYS_SUSPEND:
1489 		case APM_USER_SUSPEND:
1490 			as->suspends_read++;
1491 			break;
1492 
1493 		case APM_SYS_STANDBY:
1494 		case APM_USER_STANDBY:
1495 			as->standbys_read++;
1496 			break;
1497 		}
1498 		buf += sizeof(event);
1499 		i -= sizeof(event);
1500 	}
1501 	if (i < count)
1502 		return count - i;
1503 	if (signal_pending(current))
1504 		return -ERESTARTSYS;
1505 	return 0;
1506 }
1507 
1508 static unsigned int do_poll(struct file *fp, poll_table *wait)
1509 {
1510 	struct apm_user *as;
1511 
1512 	as = fp->private_data;
1513 	if (check_apm_user(as, "poll"))
1514 		return 0;
1515 	poll_wait(fp, &apm_waitqueue, wait);
1516 	if (!queue_empty(as))
1517 		return POLLIN | POLLRDNORM;
1518 	return 0;
1519 }
1520 
1521 static long do_ioctl(struct file *filp, u_int cmd, u_long arg)
1522 {
1523 	struct apm_user *as;
1524 	int ret;
1525 
1526 	as = filp->private_data;
1527 	if (check_apm_user(as, "ioctl"))
1528 		return -EIO;
1529 	if (!as->suser || !as->writer)
1530 		return -EPERM;
1531 	switch (cmd) {
1532 	case APM_IOC_STANDBY:
1533 		mutex_lock(&apm_mutex);
1534 		if (as->standbys_read > 0) {
1535 			as->standbys_read--;
1536 			as->standbys_pending--;
1537 			standbys_pending--;
1538 		} else
1539 			queue_event(APM_USER_STANDBY, as);
1540 		if (standbys_pending <= 0)
1541 			standby();
1542 		mutex_unlock(&apm_mutex);
1543 		break;
1544 	case APM_IOC_SUSPEND:
1545 		mutex_lock(&apm_mutex);
1546 		if (as->suspends_read > 0) {
1547 			as->suspends_read--;
1548 			as->suspends_pending--;
1549 			suspends_pending--;
1550 		} else
1551 			queue_event(APM_USER_SUSPEND, as);
1552 		if (suspends_pending <= 0) {
1553 			ret = suspend(1);
1554 			mutex_unlock(&apm_mutex);
1555 		} else {
1556 			as->suspend_wait = 1;
1557 			mutex_unlock(&apm_mutex);
1558 			wait_event_interruptible(apm_suspend_waitqueue,
1559 					as->suspend_wait == 0);
1560 			ret = as->suspend_result;
1561 		}
1562 		return ret;
1563 	default:
1564 		return -ENOTTY;
1565 	}
1566 	return 0;
1567 }
1568 
1569 static int do_release(struct inode *inode, struct file *filp)
1570 {
1571 	struct apm_user *as;
1572 
1573 	as = filp->private_data;
1574 	if (check_apm_user(as, "release"))
1575 		return 0;
1576 	filp->private_data = NULL;
1577 	if (as->standbys_pending > 0) {
1578 		standbys_pending -= as->standbys_pending;
1579 		if (standbys_pending <= 0)
1580 			standby();
1581 	}
1582 	if (as->suspends_pending > 0) {
1583 		suspends_pending -= as->suspends_pending;
1584 		if (suspends_pending <= 0)
1585 			(void) suspend(1);
1586 	}
1587 	spin_lock(&user_list_lock);
1588 	if (user_list == as)
1589 		user_list = as->next;
1590 	else {
1591 		struct apm_user *as1;
1592 
1593 		for (as1 = user_list;
1594 		     (as1 != NULL) && (as1->next != as);
1595 		     as1 = as1->next)
1596 			;
1597 		if (as1 == NULL)
1598 			pr_err("filp not in user list\n");
1599 		else
1600 			as1->next = as->next;
1601 	}
1602 	spin_unlock(&user_list_lock);
1603 	kfree(as);
1604 	return 0;
1605 }
1606 
1607 static int do_open(struct inode *inode, struct file *filp)
1608 {
1609 	struct apm_user *as;
1610 
1611 	as = kmalloc(sizeof(*as), GFP_KERNEL);
1612 	if (as == NULL)
1613 		return -ENOMEM;
1614 
1615 	as->magic = APM_BIOS_MAGIC;
1616 	as->event_tail = as->event_head = 0;
1617 	as->suspends_pending = as->standbys_pending = 0;
1618 	as->suspends_read = as->standbys_read = 0;
1619 	/*
1620 	 * XXX - this is a tiny bit broken, when we consider BSD
1621 	 * process accounting. If the device is opened by root, we
1622 	 * instantly flag that we used superuser privs. Who knows,
1623 	 * we might close the device immediately without doing a
1624 	 * privileged operation -- cevans
1625 	 */
1626 	as->suser = capable(CAP_SYS_ADMIN);
1627 	as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
1628 	as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
1629 	spin_lock(&user_list_lock);
1630 	as->next = user_list;
1631 	user_list = as;
1632 	spin_unlock(&user_list_lock);
1633 	filp->private_data = as;
1634 	return 0;
1635 }
1636 
1637 static int proc_apm_show(struct seq_file *m, void *v)
1638 {
1639 	unsigned short	bx;
1640 	unsigned short	cx;
1641 	unsigned short	dx;
1642 	int		error;
1643 	unsigned short  ac_line_status = 0xff;
1644 	unsigned short  battery_status = 0xff;
1645 	unsigned short  battery_flag   = 0xff;
1646 	int		percentage     = -1;
1647 	int             time_units     = -1;
1648 	char            *units         = "?";
1649 
1650 	if ((num_online_cpus() == 1) &&
1651 	    !(error = apm_get_power_status(&bx, &cx, &dx))) {
1652 		ac_line_status = (bx >> 8) & 0xff;
1653 		battery_status = bx & 0xff;
1654 		if ((cx & 0xff) != 0xff)
1655 			percentage = cx & 0xff;
1656 
1657 		if (apm_info.connection_version > 0x100) {
1658 			battery_flag = (cx >> 8) & 0xff;
1659 			if (dx != 0xffff) {
1660 				units = (dx & 0x8000) ? "min" : "sec";
1661 				time_units = dx & 0x7fff;
1662 			}
1663 		}
1664 	}
1665 	/* Arguments, with symbols from linux/apm_bios.h.  Information is
1666 	   from the Get Power Status (0x0a) call unless otherwise noted.
1667 
1668 	   0) Linux driver version (this will change if format changes)
1669 	   1) APM BIOS Version.  Usually 1.0, 1.1 or 1.2.
1670 	   2) APM flags from APM Installation Check (0x00):
1671 	      bit 0: APM_16_BIT_SUPPORT
1672 	      bit 1: APM_32_BIT_SUPPORT
1673 	      bit 2: APM_IDLE_SLOWS_CLOCK
1674 	      bit 3: APM_BIOS_DISABLED
1675 	      bit 4: APM_BIOS_DISENGAGED
1676 	   3) AC line status
1677 	      0x00: Off-line
1678 	      0x01: On-line
1679 	      0x02: On backup power (BIOS >= 1.1 only)
1680 	      0xff: Unknown
1681 	   4) Battery status
1682 	      0x00: High
1683 	      0x01: Low
1684 	      0x02: Critical
1685 	      0x03: Charging
1686 	      0x04: Selected battery not present (BIOS >= 1.2 only)
1687 	      0xff: Unknown
1688 	   5) Battery flag
1689 	      bit 0: High
1690 	      bit 1: Low
1691 	      bit 2: Critical
1692 	      bit 3: Charging
1693 	      bit 7: No system battery
1694 	      0xff: Unknown
1695 	   6) Remaining battery life (percentage of charge):
1696 	      0-100: valid
1697 	      -1: Unknown
1698 	   7) Remaining battery life (time units):
1699 	      Number of remaining minutes or seconds
1700 	      -1: Unknown
1701 	   8) min = minutes; sec = seconds */
1702 
1703 	seq_printf(m, "%s %d.%d 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
1704 		   driver_version,
1705 		   (apm_info.bios.version >> 8) & 0xff,
1706 		   apm_info.bios.version & 0xff,
1707 		   apm_info.bios.flags,
1708 		   ac_line_status,
1709 		   battery_status,
1710 		   battery_flag,
1711 		   percentage,
1712 		   time_units,
1713 		   units);
1714 	return 0;
1715 }
1716 
1717 static int proc_apm_open(struct inode *inode, struct file *file)
1718 {
1719 	return single_open(file, proc_apm_show, NULL);
1720 }
1721 
1722 static const struct file_operations apm_file_ops = {
1723 	.owner		= THIS_MODULE,
1724 	.open		= proc_apm_open,
1725 	.read		= seq_read,
1726 	.llseek		= seq_lseek,
1727 	.release	= single_release,
1728 };
1729 
1730 static int apm(void *unused)
1731 {
1732 	unsigned short	bx;
1733 	unsigned short	cx;
1734 	unsigned short	dx;
1735 	int		error;
1736 	char 		*power_stat;
1737 	char 		*bat_stat;
1738 
1739 	/* 2002/08/01 - WT
1740 	 * This is to avoid random crashes at boot time during initialization
1741 	 * on SMP systems in case of "apm=power-off" mode. Seen on ASUS A7M266D.
1742 	 * Some bioses don't like being called from CPU != 0.
1743 	 * Method suggested by Ingo Molnar.
1744 	 */
1745 	set_cpus_allowed_ptr(current, cpumask_of(0));
1746 	BUG_ON(smp_processor_id() != 0);
1747 
1748 	if (apm_info.connection_version == 0) {
1749 		apm_info.connection_version = apm_info.bios.version;
1750 		if (apm_info.connection_version > 0x100) {
1751 			/*
1752 			 * We only support BIOSs up to version 1.2
1753 			 */
1754 			if (apm_info.connection_version > 0x0102)
1755 				apm_info.connection_version = 0x0102;
1756 			error = apm_driver_version(&apm_info.connection_version);
1757 			if (error != APM_SUCCESS) {
1758 				apm_error("driver version", error);
1759 				/* Fall back to an APM 1.0 connection. */
1760 				apm_info.connection_version = 0x100;
1761 			}
1762 		}
1763 	}
1764 
1765 	if (debug)
1766 		printk(KERN_INFO "apm: Connection version %d.%d\n",
1767 			(apm_info.connection_version >> 8) & 0xff,
1768 			apm_info.connection_version & 0xff);
1769 
1770 #ifdef CONFIG_APM_DO_ENABLE
1771 	if (apm_info.bios.flags & APM_BIOS_DISABLED) {
1772 		/*
1773 		 * This call causes my NEC UltraLite Versa 33/C to hang if it
1774 		 * is booted with PM disabled but not in the docking station.
1775 		 * Unfortunate ...
1776 		 */
1777 		error = apm_enable_power_management(1);
1778 		if (error) {
1779 			apm_error("enable power management", error);
1780 			return -1;
1781 		}
1782 	}
1783 #endif
1784 
1785 	if ((apm_info.bios.flags & APM_BIOS_DISENGAGED)
1786 	    && (apm_info.connection_version > 0x0100)) {
1787 		error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1788 		if (error) {
1789 			apm_error("engage power management", error);
1790 			return -1;
1791 		}
1792 	}
1793 
1794 	if (debug && (num_online_cpus() == 1 || smp)) {
1795 		error = apm_get_power_status(&bx, &cx, &dx);
1796 		if (error)
1797 			printk(KERN_INFO "apm: power status not available\n");
1798 		else {
1799 			switch ((bx >> 8) & 0xff) {
1800 			case 0:
1801 				power_stat = "off line";
1802 				break;
1803 			case 1:
1804 				power_stat = "on line";
1805 				break;
1806 			case 2:
1807 				power_stat = "on backup power";
1808 				break;
1809 			default:
1810 				power_stat = "unknown";
1811 				break;
1812 			}
1813 			switch (bx & 0xff) {
1814 			case 0:
1815 				bat_stat = "high";
1816 				break;
1817 			case 1:
1818 				bat_stat = "low";
1819 				break;
1820 			case 2:
1821 				bat_stat = "critical";
1822 				break;
1823 			case 3:
1824 				bat_stat = "charging";
1825 				break;
1826 			default:
1827 				bat_stat = "unknown";
1828 				break;
1829 			}
1830 			printk(KERN_INFO
1831 			       "apm: AC %s, battery status %s, battery life ",
1832 			       power_stat, bat_stat);
1833 			if ((cx & 0xff) == 0xff)
1834 				printk("unknown\n");
1835 			else
1836 				printk("%d%%\n", cx & 0xff);
1837 			if (apm_info.connection_version > 0x100) {
1838 				printk(KERN_INFO
1839 				       "apm: battery flag 0x%02x, battery life ",
1840 				       (cx >> 8) & 0xff);
1841 				if (dx == 0xffff)
1842 					printk("unknown\n");
1843 				else
1844 					printk("%d %s\n", dx & 0x7fff,
1845 					       (dx & 0x8000) ?
1846 					       "minutes" : "seconds");
1847 			}
1848 		}
1849 	}
1850 
1851 	/* Install our power off handler.. */
1852 	if (power_off)
1853 		pm_power_off = apm_power_off;
1854 
1855 	if (num_online_cpus() == 1 || smp) {
1856 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1857 		console_blank_hook = apm_console_blank;
1858 #endif
1859 		apm_mainloop();
1860 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1861 		console_blank_hook = NULL;
1862 #endif
1863 	}
1864 
1865 	return 0;
1866 }
1867 
1868 #ifndef MODULE
1869 static int __init apm_setup(char *str)
1870 {
1871 	int invert;
1872 
1873 	while ((str != NULL) && (*str != '\0')) {
1874 		if (strncmp(str, "off", 3) == 0)
1875 			apm_disabled = 1;
1876 		if (strncmp(str, "on", 2) == 0)
1877 			apm_disabled = 0;
1878 		if ((strncmp(str, "bounce-interval=", 16) == 0) ||
1879 		    (strncmp(str, "bounce_interval=", 16) == 0))
1880 			bounce_interval = simple_strtol(str + 16, NULL, 0);
1881 		if ((strncmp(str, "idle-threshold=", 15) == 0) ||
1882 		    (strncmp(str, "idle_threshold=", 15) == 0))
1883 			idle_threshold = simple_strtol(str + 15, NULL, 0);
1884 		if ((strncmp(str, "idle-period=", 12) == 0) ||
1885 		    (strncmp(str, "idle_period=", 12) == 0))
1886 			idle_period = simple_strtol(str + 12, NULL, 0);
1887 		invert = (strncmp(str, "no-", 3) == 0) ||
1888 			(strncmp(str, "no_", 3) == 0);
1889 		if (invert)
1890 			str += 3;
1891 		if (strncmp(str, "debug", 5) == 0)
1892 			debug = !invert;
1893 		if ((strncmp(str, "power-off", 9) == 0) ||
1894 		    (strncmp(str, "power_off", 9) == 0))
1895 			power_off = !invert;
1896 		if (strncmp(str, "smp", 3) == 0) {
1897 			smp = !invert;
1898 			idle_threshold = 100;
1899 		}
1900 		if ((strncmp(str, "allow-ints", 10) == 0) ||
1901 		    (strncmp(str, "allow_ints", 10) == 0))
1902 			apm_info.allow_ints = !invert;
1903 		if ((strncmp(str, "broken-psr", 10) == 0) ||
1904 		    (strncmp(str, "broken_psr", 10) == 0))
1905 			apm_info.get_power_status_broken = !invert;
1906 		if ((strncmp(str, "realmode-power-off", 18) == 0) ||
1907 		    (strncmp(str, "realmode_power_off", 18) == 0))
1908 			apm_info.realmode_power_off = !invert;
1909 		str = strchr(str, ',');
1910 		if (str != NULL)
1911 			str += strspn(str, ", \t");
1912 	}
1913 	return 1;
1914 }
1915 
1916 __setup("apm=", apm_setup);
1917 #endif
1918 
1919 static const struct file_operations apm_bios_fops = {
1920 	.owner		= THIS_MODULE,
1921 	.read		= do_read,
1922 	.poll		= do_poll,
1923 	.unlocked_ioctl	= do_ioctl,
1924 	.open		= do_open,
1925 	.release	= do_release,
1926 	.llseek		= noop_llseek,
1927 };
1928 
1929 static struct miscdevice apm_device = {
1930 	APM_MINOR_DEV,
1931 	"apm_bios",
1932 	&apm_bios_fops
1933 };
1934 
1935 
1936 /* Simple "print if true" callback */
1937 static int __init print_if_true(const struct dmi_system_id *d)
1938 {
1939 	printk("%s\n", d->ident);
1940 	return 0;
1941 }
1942 
1943 /*
1944  * Some Bioses enable the PS/2 mouse (touchpad) at resume, even if it was
1945  * disabled before the suspend. Linux used to get terribly confused by that.
1946  */
1947 static int __init broken_ps2_resume(const struct dmi_system_id *d)
1948 {
1949 	printk(KERN_INFO "%s machine detected. Mousepad Resume Bug "
1950 	       "workaround hopefully not needed.\n", d->ident);
1951 	return 0;
1952 }
1953 
1954 /* Some bioses have a broken protected mode poweroff and need to use realmode */
1955 static int __init set_realmode_power_off(const struct dmi_system_id *d)
1956 {
1957 	if (apm_info.realmode_power_off == 0) {
1958 		apm_info.realmode_power_off = 1;
1959 		printk(KERN_INFO "%s bios detected. "
1960 		       "Using realmode poweroff only.\n", d->ident);
1961 	}
1962 	return 0;
1963 }
1964 
1965 /* Some laptops require interrupts to be enabled during APM calls */
1966 static int __init set_apm_ints(const struct dmi_system_id *d)
1967 {
1968 	if (apm_info.allow_ints == 0) {
1969 		apm_info.allow_ints = 1;
1970 		printk(KERN_INFO "%s machine detected. "
1971 		       "Enabling interrupts during APM calls.\n", d->ident);
1972 	}
1973 	return 0;
1974 }
1975 
1976 /* Some APM bioses corrupt memory or just plain do not work */
1977 static int __init apm_is_horked(const struct dmi_system_id *d)
1978 {
1979 	if (apm_info.disabled == 0) {
1980 		apm_info.disabled = 1;
1981 		printk(KERN_INFO "%s machine detected. "
1982 		       "Disabling APM.\n", d->ident);
1983 	}
1984 	return 0;
1985 }
1986 
1987 static int __init apm_is_horked_d850md(const struct dmi_system_id *d)
1988 {
1989 	if (apm_info.disabled == 0) {
1990 		apm_info.disabled = 1;
1991 		printk(KERN_INFO "%s machine detected. "
1992 		       "Disabling APM.\n", d->ident);
1993 		printk(KERN_INFO "This bug is fixed in bios P15 which is available for\n");
1994 		printk(KERN_INFO "download from support.intel.com\n");
1995 	}
1996 	return 0;
1997 }
1998 
1999 /* Some APM bioses hang on APM idle calls */
2000 static int __init apm_likes_to_melt(const struct dmi_system_id *d)
2001 {
2002 	if (apm_info.forbid_idle == 0) {
2003 		apm_info.forbid_idle = 1;
2004 		printk(KERN_INFO "%s machine detected. "
2005 		       "Disabling APM idle calls.\n", d->ident);
2006 	}
2007 	return 0;
2008 }
2009 
2010 /*
2011  *  Check for clue free BIOS implementations who use
2012  *  the following QA technique
2013  *
2014  *      [ Write BIOS Code ]<------
2015  *               |                ^
2016  *      < Does it Compile >----N--
2017  *               |Y               ^
2018  *	< Does it Boot Win98 >-N--
2019  *               |Y
2020  *           [Ship It]
2021  *
2022  *	Phoenix A04  08/24/2000 is known bad (Dell Inspiron 5000e)
2023  *	Phoenix A07  09/29/2000 is known good (Dell Inspiron 5000)
2024  */
2025 static int __init broken_apm_power(const struct dmi_system_id *d)
2026 {
2027 	apm_info.get_power_status_broken = 1;
2028 	printk(KERN_WARNING "BIOS strings suggest APM bugs, "
2029 	       "disabling power status reporting.\n");
2030 	return 0;
2031 }
2032 
2033 /*
2034  * This bios swaps the APM minute reporting bytes over (Many sony laptops
2035  * have this problem).
2036  */
2037 static int __init swab_apm_power_in_minutes(const struct dmi_system_id *d)
2038 {
2039 	apm_info.get_power_status_swabinminutes = 1;
2040 	printk(KERN_WARNING "BIOS strings suggest APM reports battery life "
2041 	       "in minutes and wrong byte order.\n");
2042 	return 0;
2043 }
2044 
2045 static struct dmi_system_id __initdata apm_dmi_table[] = {
2046 	{
2047 		print_if_true,
2048 		KERN_WARNING "IBM T23 - BIOS 1.03b+ and controller firmware 1.02+ may be needed for Linux APM.",
2049 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
2050 			DMI_MATCH(DMI_BIOS_VERSION, "1AET38WW (1.01b)"), },
2051 	},
2052 	{	/* Handle problems with APM on the C600 */
2053 		broken_ps2_resume, "Dell Latitude C600",
2054 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
2055 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C600"), },
2056 	},
2057 	{	/* Allow interrupts during suspend on Dell Latitude laptops*/
2058 		set_apm_ints, "Dell Latitude",
2059 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2060 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C510"), }
2061 	},
2062 	{	/* APM crashes */
2063 		apm_is_horked, "Dell Inspiron 2500",
2064 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2065 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2066 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2067 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2068 	},
2069 	{	/* Allow interrupts during suspend on Dell Inspiron laptops*/
2070 		set_apm_ints, "Dell Inspiron", {
2071 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2072 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 4000"), },
2073 	},
2074 	{	/* Handle problems with APM on Inspiron 5000e */
2075 		broken_apm_power, "Dell Inspiron 5000e",
2076 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2077 			DMI_MATCH(DMI_BIOS_VERSION, "A04"),
2078 			DMI_MATCH(DMI_BIOS_DATE, "08/24/2000"), },
2079 	},
2080 	{	/* Handle problems with APM on Inspiron 2500 */
2081 		broken_apm_power, "Dell Inspiron 2500",
2082 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2083 			DMI_MATCH(DMI_BIOS_VERSION, "A12"),
2084 			DMI_MATCH(DMI_BIOS_DATE, "02/04/2002"), },
2085 	},
2086 	{	/* APM crashes */
2087 		apm_is_horked, "Dell Dimension 4100",
2088 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2089 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"),
2090 			DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2091 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2092 	},
2093 	{	/* Allow interrupts during suspend on Compaq Laptops*/
2094 		set_apm_ints, "Compaq 12XL125",
2095 		{	DMI_MATCH(DMI_SYS_VENDOR, "Compaq"),
2096 			DMI_MATCH(DMI_PRODUCT_NAME, "Compaq PC"),
2097 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2098 			DMI_MATCH(DMI_BIOS_VERSION, "4.06"), },
2099 	},
2100 	{	/* Allow interrupts during APM or the clock goes slow */
2101 		set_apm_ints, "ASUSTeK",
2102 		{	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
2103 			DMI_MATCH(DMI_PRODUCT_NAME, "L8400K series Notebook PC"), },
2104 	},
2105 	{	/* APM blows on shutdown */
2106 		apm_is_horked, "ABIT KX7-333[R]",
2107 		{	DMI_MATCH(DMI_BOARD_VENDOR, "ABIT"),
2108 			DMI_MATCH(DMI_BOARD_NAME, "VT8367-8233A (KX7-333[R])"), },
2109 	},
2110 	{	/* APM crashes */
2111 		apm_is_horked, "Trigem Delhi3",
2112 		{	DMI_MATCH(DMI_SYS_VENDOR, "TriGem Computer, Inc"),
2113 			DMI_MATCH(DMI_PRODUCT_NAME, "Delhi3"), },
2114 	},
2115 	{	/* APM crashes */
2116 		apm_is_horked, "Fujitsu-Siemens",
2117 		{	DMI_MATCH(DMI_BIOS_VENDOR, "hoenix/FUJITSU SIEMENS"),
2118 			DMI_MATCH(DMI_BIOS_VERSION, "Version1.01"), },
2119 	},
2120 	{	/* APM crashes */
2121 		apm_is_horked_d850md, "Intel D850MD",
2122 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2123 			DMI_MATCH(DMI_BIOS_VERSION, "MV85010A.86A.0016.P07.0201251536"), },
2124 	},
2125 	{	/* APM crashes */
2126 		apm_is_horked, "Intel D810EMO",
2127 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2128 			DMI_MATCH(DMI_BIOS_VERSION, "MO81010A.86A.0008.P04.0004170800"), },
2129 	},
2130 	{	/* APM crashes */
2131 		apm_is_horked, "Dell XPS-Z",
2132 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2133 			DMI_MATCH(DMI_BIOS_VERSION, "A11"),
2134 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"), },
2135 	},
2136 	{	/* APM crashes */
2137 		apm_is_horked, "Sharp PC-PJ/AX",
2138 		{	DMI_MATCH(DMI_SYS_VENDOR, "SHARP"),
2139 			DMI_MATCH(DMI_PRODUCT_NAME, "PC-PJ/AX"),
2140 			DMI_MATCH(DMI_BIOS_VENDOR, "SystemSoft"),
2141 			DMI_MATCH(DMI_BIOS_VERSION, "Version R2.08"), },
2142 	},
2143 	{	/* APM crashes */
2144 		apm_is_horked, "Dell Inspiron 2500",
2145 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2146 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2147 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2148 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2149 	},
2150 	{	/* APM idle hangs */
2151 		apm_likes_to_melt, "Jabil AMD",
2152 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2153 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP06"), },
2154 	},
2155 	{	/* APM idle hangs */
2156 		apm_likes_to_melt, "AMI Bios",
2157 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2158 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP05"), },
2159 	},
2160 	{	/* Handle problems with APM on Sony Vaio PCG-N505X(DE) */
2161 		swab_apm_power_in_minutes, "Sony VAIO",
2162 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2163 			DMI_MATCH(DMI_BIOS_VERSION, "R0206H"),
2164 			DMI_MATCH(DMI_BIOS_DATE, "08/23/99"), },
2165 	},
2166 	{	/* Handle problems with APM on Sony Vaio PCG-N505VX */
2167 		swab_apm_power_in_minutes, "Sony VAIO",
2168 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2169 			DMI_MATCH(DMI_BIOS_VERSION, "W2K06H0"),
2170 			DMI_MATCH(DMI_BIOS_DATE, "02/03/00"), },
2171 	},
2172 	{	/* Handle problems with APM on Sony Vaio PCG-XG29 */
2173 		swab_apm_power_in_minutes, "Sony VAIO",
2174 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2175 			DMI_MATCH(DMI_BIOS_VERSION, "R0117A0"),
2176 			DMI_MATCH(DMI_BIOS_DATE, "04/25/00"), },
2177 	},
2178 	{	/* Handle problems with APM on Sony Vaio PCG-Z600NE */
2179 		swab_apm_power_in_minutes, "Sony VAIO",
2180 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2181 			DMI_MATCH(DMI_BIOS_VERSION, "R0121Z1"),
2182 			DMI_MATCH(DMI_BIOS_DATE, "05/11/00"), },
2183 	},
2184 	{	/* Handle problems with APM on Sony Vaio PCG-Z600NE */
2185 		swab_apm_power_in_minutes, "Sony VAIO",
2186 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2187 			DMI_MATCH(DMI_BIOS_VERSION, "WME01Z1"),
2188 			DMI_MATCH(DMI_BIOS_DATE, "08/11/00"), },
2189 	},
2190 	{	/* Handle problems with APM on Sony Vaio PCG-Z600LEK(DE) */
2191 		swab_apm_power_in_minutes, "Sony VAIO",
2192 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2193 			DMI_MATCH(DMI_BIOS_VERSION, "R0206Z3"),
2194 			DMI_MATCH(DMI_BIOS_DATE, "12/25/00"), },
2195 	},
2196 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS */
2197 		swab_apm_power_in_minutes, "Sony VAIO",
2198 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2199 			DMI_MATCH(DMI_BIOS_VERSION, "R0203D0"),
2200 			DMI_MATCH(DMI_BIOS_DATE, "05/12/00"), },
2201 	},
2202 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS */
2203 		swab_apm_power_in_minutes, "Sony VAIO",
2204 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2205 			DMI_MATCH(DMI_BIOS_VERSION, "R0203Z3"),
2206 			DMI_MATCH(DMI_BIOS_DATE, "08/25/00"), },
2207 	},
2208 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS (with updated BIOS) */
2209 		swab_apm_power_in_minutes, "Sony VAIO",
2210 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2211 			DMI_MATCH(DMI_BIOS_VERSION, "R0209Z3"),
2212 			DMI_MATCH(DMI_BIOS_DATE, "05/12/01"), },
2213 	},
2214 	{	/* Handle problems with APM on Sony Vaio PCG-F104K */
2215 		swab_apm_power_in_minutes, "Sony VAIO",
2216 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2217 			DMI_MATCH(DMI_BIOS_VERSION, "R0204K2"),
2218 			DMI_MATCH(DMI_BIOS_DATE, "08/28/00"), },
2219 	},
2220 
2221 	{	/* Handle problems with APM on Sony Vaio PCG-C1VN/C1VE */
2222 		swab_apm_power_in_minutes, "Sony VAIO",
2223 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2224 			DMI_MATCH(DMI_BIOS_VERSION, "R0208P1"),
2225 			DMI_MATCH(DMI_BIOS_DATE, "11/09/00"), },
2226 	},
2227 	{	/* Handle problems with APM on Sony Vaio PCG-C1VE */
2228 		swab_apm_power_in_minutes, "Sony VAIO",
2229 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2230 			DMI_MATCH(DMI_BIOS_VERSION, "R0204P1"),
2231 			DMI_MATCH(DMI_BIOS_DATE, "09/12/00"), },
2232 	},
2233 	{	/* Handle problems with APM on Sony Vaio PCG-C1VE */
2234 		swab_apm_power_in_minutes, "Sony VAIO",
2235 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2236 			DMI_MATCH(DMI_BIOS_VERSION, "WXPO1Z3"),
2237 			DMI_MATCH(DMI_BIOS_DATE, "10/26/01"), },
2238 	},
2239 	{	/* broken PM poweroff bios */
2240 		set_realmode_power_off, "Award Software v4.60 PGMA",
2241 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Award Software International, Inc."),
2242 			DMI_MATCH(DMI_BIOS_VERSION, "4.60 PGMA"),
2243 			DMI_MATCH(DMI_BIOS_DATE, "134526184"), },
2244 	},
2245 
2246 	/* Generic per vendor APM settings  */
2247 
2248 	{	/* Allow interrupts during suspend on IBM laptops */
2249 		set_apm_ints, "IBM",
2250 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"), },
2251 	},
2252 
2253 	{ }
2254 };
2255 
2256 /*
2257  * Just start the APM thread. We do NOT want to do APM BIOS
2258  * calls from anything but the APM thread, if for no other reason
2259  * than the fact that we don't trust the APM BIOS. This way,
2260  * most common APM BIOS problems that lead to protection errors
2261  * etc will have at least some level of being contained...
2262  *
2263  * In short, if something bad happens, at least we have a choice
2264  * of just killing the apm thread..
2265  */
2266 static int __init apm_init(void)
2267 {
2268 	struct desc_struct *gdt;
2269 	int err;
2270 
2271 	dmi_check_system(apm_dmi_table);
2272 
2273 	if (apm_info.bios.version == 0 || machine_is_olpc()) {
2274 		printk(KERN_INFO "apm: BIOS not found.\n");
2275 		return -ENODEV;
2276 	}
2277 	printk(KERN_INFO
2278 	       "apm: BIOS version %d.%d Flags 0x%02x (Driver version %s)\n",
2279 	       ((apm_info.bios.version >> 8) & 0xff),
2280 	       (apm_info.bios.version & 0xff),
2281 	       apm_info.bios.flags,
2282 	       driver_version);
2283 	if ((apm_info.bios.flags & APM_32_BIT_SUPPORT) == 0) {
2284 		printk(KERN_INFO "apm: no 32 bit BIOS support\n");
2285 		return -ENODEV;
2286 	}
2287 
2288 	if (allow_ints)
2289 		apm_info.allow_ints = 1;
2290 	if (broken_psr)
2291 		apm_info.get_power_status_broken = 1;
2292 	if (realmode_power_off)
2293 		apm_info.realmode_power_off = 1;
2294 	/* User can override, but default is to trust DMI */
2295 	if (apm_disabled != -1)
2296 		apm_info.disabled = apm_disabled;
2297 
2298 	/*
2299 	 * Fix for the Compaq Contura 3/25c which reports BIOS version 0.1
2300 	 * but is reportedly a 1.0 BIOS.
2301 	 */
2302 	if (apm_info.bios.version == 0x001)
2303 		apm_info.bios.version = 0x100;
2304 
2305 	/* BIOS < 1.2 doesn't set cseg_16_len */
2306 	if (apm_info.bios.version < 0x102)
2307 		apm_info.bios.cseg_16_len = 0; /* 64k */
2308 
2309 	if (debug) {
2310 		printk(KERN_INFO "apm: entry %x:%x cseg16 %x dseg %x",
2311 			apm_info.bios.cseg, apm_info.bios.offset,
2312 			apm_info.bios.cseg_16, apm_info.bios.dseg);
2313 		if (apm_info.bios.version > 0x100)
2314 			printk(" cseg len %x, dseg len %x",
2315 				apm_info.bios.cseg_len,
2316 				apm_info.bios.dseg_len);
2317 		if (apm_info.bios.version > 0x101)
2318 			printk(" cseg16 len %x", apm_info.bios.cseg_16_len);
2319 		printk("\n");
2320 	}
2321 
2322 	if (apm_info.disabled) {
2323 		pr_notice("disabled on user request.\n");
2324 		return -ENODEV;
2325 	}
2326 	if ((num_online_cpus() > 1) && !power_off && !smp) {
2327 		pr_notice("disabled - APM is not SMP safe.\n");
2328 		apm_info.disabled = 1;
2329 		return -ENODEV;
2330 	}
2331 	if (!acpi_disabled) {
2332 		pr_notice("overridden by ACPI.\n");
2333 		apm_info.disabled = 1;
2334 		return -ENODEV;
2335 	}
2336 
2337 	/*
2338 	 * Set up the long jump entry point to the APM BIOS, which is called
2339 	 * from inline assembly.
2340 	 */
2341 	apm_bios_entry.offset = apm_info.bios.offset;
2342 	apm_bios_entry.segment = APM_CS;
2343 
2344 	/*
2345 	 * The APM 1.1 BIOS is supposed to provide limit information that it
2346 	 * recognizes.  Many machines do this correctly, but many others do
2347 	 * not restrict themselves to their claimed limit.  When this happens,
2348 	 * they will cause a segmentation violation in the kernel at boot time.
2349 	 * Most BIOS's, however, will respect a 64k limit, so we use that.
2350 	 *
2351 	 * Note we only set APM segments on CPU zero, since we pin the APM
2352 	 * code to that CPU.
2353 	 */
2354 	gdt = get_cpu_gdt_table(0);
2355 	set_desc_base(&gdt[APM_CS >> 3],
2356 		 (unsigned long)__va((unsigned long)apm_info.bios.cseg << 4));
2357 	set_desc_base(&gdt[APM_CS_16 >> 3],
2358 		 (unsigned long)__va((unsigned long)apm_info.bios.cseg_16 << 4));
2359 	set_desc_base(&gdt[APM_DS >> 3],
2360 		 (unsigned long)__va((unsigned long)apm_info.bios.dseg << 4));
2361 
2362 	proc_create("apm", 0, NULL, &apm_file_ops);
2363 
2364 	kapmd_task = kthread_create(apm, NULL, "kapmd");
2365 	if (IS_ERR(kapmd_task)) {
2366 		pr_err("disabled - Unable to start kernel thread\n");
2367 		err = PTR_ERR(kapmd_task);
2368 		kapmd_task = NULL;
2369 		remove_proc_entry("apm", NULL);
2370 		return err;
2371 	}
2372 	wake_up_process(kapmd_task);
2373 
2374 	if (num_online_cpus() > 1 && !smp) {
2375 		printk(KERN_NOTICE
2376 		       "apm: disabled - APM is not SMP safe (power off active).\n");
2377 		return 0;
2378 	}
2379 
2380 	/*
2381 	 * Note we don't actually care if the misc_device cannot be registered.
2382 	 * this driver can do its job without it, even if userspace can't
2383 	 * control it.  just log the error
2384 	 */
2385 	if (misc_register(&apm_device))
2386 		printk(KERN_WARNING "apm: Could not register misc device.\n");
2387 
2388 	if (HZ != 100)
2389 		idle_period = (idle_period * HZ) / 100;
2390 	if (idle_threshold < 100) {
2391 		if (!cpuidle_register_driver(&apm_idle_driver))
2392 			if (cpuidle_register_device(&apm_cpuidle_device))
2393 				cpuidle_unregister_driver(&apm_idle_driver);
2394 	}
2395 
2396 	return 0;
2397 }
2398 
2399 static void __exit apm_exit(void)
2400 {
2401 	int error;
2402 
2403 	cpuidle_unregister_device(&apm_cpuidle_device);
2404 	cpuidle_unregister_driver(&apm_idle_driver);
2405 
2406 	if (((apm_info.bios.flags & APM_BIOS_DISENGAGED) == 0)
2407 	    && (apm_info.connection_version > 0x0100)) {
2408 		error = apm_engage_power_management(APM_DEVICE_ALL, 0);
2409 		if (error)
2410 			apm_error("disengage power management", error);
2411 	}
2412 	misc_deregister(&apm_device);
2413 	remove_proc_entry("apm", NULL);
2414 	if (power_off)
2415 		pm_power_off = NULL;
2416 	if (kapmd_task) {
2417 		kthread_stop(kapmd_task);
2418 		kapmd_task = NULL;
2419 	}
2420 }
2421 
2422 module_init(apm_init);
2423 module_exit(apm_exit);
2424 
2425 MODULE_AUTHOR("Stephen Rothwell");
2426 MODULE_DESCRIPTION("Advanced Power Management");
2427 MODULE_LICENSE("GPL");
2428 module_param(debug, bool, 0644);
2429 MODULE_PARM_DESC(debug, "Enable debug mode");
2430 module_param(power_off, bool, 0444);
2431 MODULE_PARM_DESC(power_off, "Enable power off");
2432 module_param(bounce_interval, int, 0444);
2433 MODULE_PARM_DESC(bounce_interval,
2434 		"Set the number of ticks to ignore suspend bounces");
2435 module_param(allow_ints, bool, 0444);
2436 MODULE_PARM_DESC(allow_ints, "Allow interrupts during BIOS calls");
2437 module_param(broken_psr, bool, 0444);
2438 MODULE_PARM_DESC(broken_psr, "BIOS has a broken GetPowerStatus call");
2439 module_param(realmode_power_off, bool, 0444);
2440 MODULE_PARM_DESC(realmode_power_off,
2441 		"Switch to real mode before powering off");
2442 module_param(idle_threshold, int, 0444);
2443 MODULE_PARM_DESC(idle_threshold,
2444 	"System idle percentage above which to make APM BIOS idle calls");
2445 module_param(idle_period, int, 0444);
2446 MODULE_PARM_DESC(idle_period,
2447 	"Period (in sec/100) over which to caculate the idle percentage");
2448 module_param(smp, bool, 0444);
2449 MODULE_PARM_DESC(smp,
2450 	"Set this to enable APM use on an SMP platform. Use with caution on older systems");
2451 MODULE_ALIAS_MISCDEV(APM_MINOR_DEV);
2452