xref: /openbmc/linux/arch/x86/kernel/apm_32.c (revision f71a261a)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* -*- linux-c -*-
3  * APM BIOS driver for Linux
4  * Copyright 1994-2001 Stephen Rothwell (sfr@canb.auug.org.au)
5  *
6  * Initial development of this driver was funded by NEC Australia P/L
7  *	and NEC Corporation
8  *
9  * October 1995, Rik Faith (faith@cs.unc.edu):
10  *    Minor enhancements and updates (to the patch set) for 1.3.x
11  *    Documentation
12  * January 1996, Rik Faith (faith@cs.unc.edu):
13  *    Make /proc/apm easy to format (bump driver version)
14  * March 1996, Rik Faith (faith@cs.unc.edu):
15  *    Prohibit APM BIOS calls unless apm_enabled.
16  *    (Thanks to Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>)
17  * April 1996, Stephen Rothwell (sfr@canb.auug.org.au)
18  *    Version 1.0 and 1.1
19  * May 1996, Version 1.2
20  * Feb 1998, Version 1.3
21  * Feb 1998, Version 1.4
22  * Aug 1998, Version 1.5
23  * Sep 1998, Version 1.6
24  * Nov 1998, Version 1.7
25  * Jan 1999, Version 1.8
26  * Jan 1999, Version 1.9
27  * Oct 1999, Version 1.10
28  * Nov 1999, Version 1.11
29  * Jan 2000, Version 1.12
30  * Feb 2000, Version 1.13
31  * Nov 2000, Version 1.14
32  * Oct 2001, Version 1.15
33  * Jan 2002, Version 1.16
34  * Oct 2002, Version 1.16ac
35  *
36  * History:
37  *    0.6b: first version in official kernel, Linux 1.3.46
38  *    0.7: changed /proc/apm format, Linux 1.3.58
39  *    0.8: fixed gcc 2.7.[12] compilation problems, Linux 1.3.59
40  *    0.9: only call bios if bios is present, Linux 1.3.72
41  *    1.0: use fixed device number, consolidate /proc/apm into this file,
42  *         Linux 1.3.85
43  *    1.1: support user-space standby and suspend, power off after system
44  *         halted, Linux 1.3.98
45  *    1.2: When resetting RTC after resume, take care so that the time
46  *         is only incorrect by 30-60mS (vs. 1S previously) (Gabor J. Toth
47  *         <jtoth@princeton.edu>); improve interaction between
48  *         screen-blanking and gpm (Stephen Rothwell); Linux 1.99.4
49  *    1.2a:Simple change to stop mysterious bug reports with SMP also added
50  *	   levels to the printk calls. APM is not defined for SMP machines.
51  *         The new replacement for it is, but Linux doesn't yet support this.
52  *         Alan Cox Linux 2.1.55
53  *    1.3: Set up a valid data descriptor 0x40 for buggy BIOS's
54  *    1.4: Upgraded to support APM 1.2. Integrated ThinkPad suspend patch by
55  *         Dean Gaudet <dgaudet@arctic.org>.
56  *         C. Scott Ananian <cananian@alumni.princeton.edu> Linux 2.1.87
57  *    1.5: Fix segment register reloading (in case of bad segments saved
58  *         across BIOS call).
59  *         Stephen Rothwell
60  *    1.6: Cope with compiler/assembler differences.
61  *         Only try to turn off the first display device.
62  *         Fix OOPS at power off with no APM BIOS by Jan Echternach
63  *                   <echter@informatik.uni-rostock.de>
64  *         Stephen Rothwell
65  *    1.7: Modify driver's cached copy of the disabled/disengaged flags
66  *         to reflect current state of APM BIOS.
67  *         Chris Rankin <rankinc@bellsouth.net>
68  *         Reset interrupt 0 timer to 100Hz after suspend
69  *         Chad Miller <cmiller@surfsouth.com>
70  *         Add CONFIG_APM_IGNORE_SUSPEND_BOUNCE
71  *         Richard Gooch <rgooch@atnf.csiro.au>
72  *         Allow boot time disabling of APM
73  *         Make boot messages far less verbose by default
74  *         Make asm safer
75  *         Stephen Rothwell
76  *    1.8: Add CONFIG_APM_RTC_IS_GMT
77  *         Richard Gooch <rgooch@atnf.csiro.au>
78  *         change APM_NOINTS to CONFIG_APM_ALLOW_INTS
79  *         remove dependency on CONFIG_PROC_FS
80  *         Stephen Rothwell
81  *    1.9: Fix small typo.  <laslo@wodip.opole.pl>
82  *         Try to cope with BIOS's that need to have all display
83  *         devices blanked and not just the first one.
84  *         Ross Paterson <ross@soi.city.ac.uk>
85  *         Fix segment limit setting it has always been wrong as
86  *         the segments needed to have byte granularity.
87  *         Mark a few things __init.
88  *         Add hack to allow power off of SMP systems by popular request.
89  *         Use CONFIG_SMP instead of __SMP__
90  *         Ignore BOUNCES for three seconds.
91  *         Stephen Rothwell
92  *   1.10: Fix for Thinkpad return code.
93  *         Merge 2.2 and 2.3 drivers.
94  *         Remove APM dependencies in arch/i386/kernel/process.c
95  *         Remove APM dependencies in drivers/char/sysrq.c
96  *         Reset time across standby.
97  *         Allow more initialisation on SMP.
98  *         Remove CONFIG_APM_POWER_OFF and make it boot time
99  *         configurable (default on).
100  *         Make debug only a boot time parameter (remove APM_DEBUG).
101  *         Try to blank all devices on any error.
102  *   1.11: Remove APM dependencies in drivers/char/console.c
103  *         Check nr_running to detect if we are idle (from
104  *         Borislav Deianov <borislav@lix.polytechnique.fr>)
105  *         Fix for bioses that don't zero the top part of the
106  *         entrypoint offset (Mario Sitta <sitta@al.unipmn.it>)
107  *         (reported by Panos Katsaloulis <teras@writeme.com>).
108  *         Real mode power off patch (Walter Hofmann
109  *         <Walter.Hofmann@physik.stud.uni-erlangen.de>).
110  *   1.12: Remove CONFIG_SMP as the compiler will optimize
111  *         the code away anyway (smp_num_cpus == 1 in UP)
112  *         noted by Artur Skawina <skawina@geocities.com>.
113  *         Make power off under SMP work again.
114  *         Fix thinko with initial engaging of BIOS.
115  *         Make sure power off only happens on CPU 0
116  *         (Paul "Rusty" Russell <rusty@rustcorp.com.au>).
117  *         Do error notification to user mode if BIOS calls fail.
118  *         Move entrypoint offset fix to ...boot/setup.S
119  *         where it belongs (Cosmos <gis88564@cis.nctu.edu.tw>).
120  *         Remove smp-power-off. SMP users must now specify
121  *         "apm=power-off" on the kernel command line. Suggested
122  *         by Jim Avera <jima@hal.com>, modified by Alan Cox
123  *         <alan@lxorguk.ukuu.org.uk>.
124  *         Register the /proc/apm entry even on SMP so that
125  *         scripts that check for it before doing power off
126  *         work (Jim Avera <jima@hal.com>).
127  *   1.13: Changes for new pm_ interfaces (Andy Henroid
128  *         <andy_henroid@yahoo.com>).
129  *         Modularize the code.
130  *         Fix the Thinkpad (again) :-( (CONFIG_APM_IGNORE_MULTIPLE_SUSPENDS
131  *         is now the way life works).
132  *         Fix thinko in suspend() (wrong return).
133  *         Notify drivers on critical suspend.
134  *         Make kapmd absorb more idle time (Pavel Machek <pavel@ucw.cz>
135  *         modified by sfr).
136  *         Disable interrupts while we are suspended (Andy Henroid
137  *         <andy_henroid@yahoo.com> fixed by sfr).
138  *         Make power off work on SMP again (Tony Hoyle
139  *         <tmh@magenta-logic.com> and <zlatko@iskon.hr>) modified by sfr.
140  *         Remove CONFIG_APM_SUSPEND_BOUNCE.  The bounce ignore
141  *         interval is now configurable.
142  *   1.14: Make connection version persist across module unload/load.
143  *         Enable and engage power management earlier.
144  *         Disengage power management on module unload.
145  *         Changed to use the sysrq-register hack for registering the
146  *         power off function called by magic sysrq based upon discussions
147  *         in irc://irc.openprojects.net/#kernelnewbies
148  *         (Crutcher Dunnavant <crutcher+kernel@datastacks.com>).
149  *         Make CONFIG_APM_REAL_MODE_POWER_OFF run time configurable.
150  *         (Arjan van de Ven <arjanv@redhat.com>) modified by sfr.
151  *         Work around byte swap bug in one of the Vaio's BIOS's
152  *         (Marc Boucher <marc@mbsi.ca>).
153  *         Exposed the disable flag to dmi so that we can handle known
154  *         broken APM (Alan Cox <alan@lxorguk.ukuu.org.uk>).
155  *   1.14ac: If the BIOS says "I slowed the CPU down" then don't spin
156  *         calling it - instead idle. (Alan Cox <alan@lxorguk.ukuu.org.uk>)
157  *         If an APM idle fails log it and idle sensibly
158  *   1.15: Don't queue events to clients who open the device O_WRONLY.
159  *         Don't expect replies from clients who open the device O_RDONLY.
160  *         (Idea from Thomas Hood)
161  *         Minor waitqueue cleanups. (John Fremlin <chief@bandits.org>)
162  *   1.16: Fix idle calling. (Andreas Steinmetz <ast@domdv.de> et al.)
163  *         Notify listeners of standby or suspend events before notifying
164  *         drivers. Return EBUSY to ioctl() if suspend is rejected.
165  *         (Russell King <rmk@arm.linux.org.uk> and Thomas Hood)
166  *         Ignore first resume after we generate our own resume event
167  *         after a suspend (Thomas Hood)
168  *         Daemonize now gets rid of our controlling terminal (sfr).
169  *         CONFIG_APM_CPU_IDLE now just affects the default value of
170  *         idle_threshold (sfr).
171  *         Change name of kernel apm daemon (as it no longer idles) (sfr).
172  *   1.16ac: Fix up SMP support somewhat. You can now force SMP on and we
173  *	   make _all_ APM calls on the CPU#0. Fix unsafe sign bug.
174  *	   TODO: determine if its "boot CPU" or "CPU0" we want to lock to.
175  *
176  * APM 1.1 Reference:
177  *
178  *   Intel Corporation, Microsoft Corporation. Advanced Power Management
179  *   (APM) BIOS Interface Specification, Revision 1.1, September 1993.
180  *   Intel Order Number 241704-001.  Microsoft Part Number 781-110-X01.
181  *
182  * [This document is available free from Intel by calling 800.628.8686 (fax
183  * 916.356.6100) or 800.548.4725; or from
184  * http://www.microsoft.com/whdc/archive/amp_12.mspx  It is also
185  * available from Microsoft by calling 206.882.8080.]
186  *
187  * APM 1.2 Reference:
188  *   Intel Corporation, Microsoft Corporation. Advanced Power Management
189  *   (APM) BIOS Interface Specification, Revision 1.2, February 1996.
190  *
191  * [This document is available from Microsoft at:
192  *    http://www.microsoft.com/whdc/archive/amp_12.mspx]
193  */
194 
195 #define pr_fmt(fmt) "apm: " fmt
196 
197 #include <linux/module.h>
198 
199 #include <linux/poll.h>
200 #include <linux/types.h>
201 #include <linux/stddef.h>
202 #include <linux/timer.h>
203 #include <linux/fcntl.h>
204 #include <linux/slab.h>
205 #include <linux/stat.h>
206 #include <linux/proc_fs.h>
207 #include <linux/seq_file.h>
208 #include <linux/miscdevice.h>
209 #include <linux/apm_bios.h>
210 #include <linux/init.h>
211 #include <linux/time.h>
212 #include <linux/sched/signal.h>
213 #include <linux/sched/cputime.h>
214 #include <linux/pm.h>
215 #include <linux/capability.h>
216 #include <linux/device.h>
217 #include <linux/kernel.h>
218 #include <linux/freezer.h>
219 #include <linux/smp.h>
220 #include <linux/dmi.h>
221 #include <linux/suspend.h>
222 #include <linux/kthread.h>
223 #include <linux/jiffies.h>
224 #include <linux/acpi.h>
225 #include <linux/syscore_ops.h>
226 #include <linux/i8253.h>
227 #include <linux/cpuidle.h>
228 
229 #include <linux/uaccess.h>
230 #include <asm/desc.h>
231 #include <asm/olpc.h>
232 #include <asm/paravirt.h>
233 #include <asm/reboot.h>
234 #include <asm/nospec-branch.h>
235 #include <asm/ibt.h>
236 
237 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
238 extern int (*console_blank_hook)(int);
239 #endif
240 
241 /*
242  * The apm_bios device is one of the misc char devices.
243  * This is its minor number.
244  */
245 #define	APM_MINOR_DEV	134
246 
247 /*
248  * Various options can be changed at boot time as follows:
249  * (We allow underscores for compatibility with the modules code)
250  *	apm=on/off			enable/disable APM
251  *	    [no-]allow[-_]ints		allow interrupts during BIOS calls
252  *	    [no-]broken[-_]psr		BIOS has a broken GetPowerStatus call
253  *	    [no-]realmode[-_]power[-_]off	switch to real mode before
254  *	    					powering off
255  *	    [no-]debug			log some debugging messages
256  *	    [no-]power[-_]off		power off on shutdown
257  *	    [no-]smp			Use apm even on an SMP box
258  *	    bounce[-_]interval=<n>	number of ticks to ignore suspend
259  *	    				bounces
260  *          idle[-_]threshold=<n>       System idle percentage above which to
261  *                                      make APM BIOS idle calls. Set it to
262  *                                      100 to disable.
263  *          idle[-_]period=<n>          Period (in 1/100s of a second) over
264  *                                      which the idle percentage is
265  *                                      calculated.
266  */
267 
268 /* KNOWN PROBLEM MACHINES:
269  *
270  * U: TI 4000M TravelMate: BIOS is *NOT* APM compliant
271  *                         [Confirmed by TI representative]
272  * ?: ACER 486DX4/75: uses dseg 0040, in violation of APM specification
273  *                    [Confirmed by BIOS disassembly]
274  *                    [This may work now ...]
275  * P: Toshiba 1950S: battery life information only gets updated after resume
276  * P: Midwest Micro Soundbook Elite DX2/66 monochrome: screen blanking
277  * 	broken in BIOS [Reported by Garst R. Reese <reese@isn.net>]
278  * ?: AcerNote-950: oops on reading /proc/apm - workaround is a WIP
279  * 	Neale Banks <neale@lowendale.com.au> December 2000
280  *
281  * Legend: U = unusable with APM patches
282  *         P = partially usable with APM patches
283  */
284 
285 /*
286  * Define as 1 to make the driver always call the APM BIOS busy
287  * routine even if the clock was not reported as slowed by the
288  * idle routine.  Otherwise, define as 0.
289  */
290 #define ALWAYS_CALL_BUSY   1
291 
292 /*
293  * Define to make the APM BIOS calls zero all data segment registers (so
294  * that an incorrect BIOS implementation will cause a kernel panic if it
295  * tries to write to arbitrary memory).
296  */
297 #define APM_ZERO_SEGS
298 
299 #include <asm/apm.h>
300 
301 /*
302  * Define to re-initialize the interrupt 0 timer to 100 Hz after a suspend.
303  * This patched by Chad Miller <cmiller@surfsouth.com>, original code by
304  * David Chen <chen@ctpa04.mit.edu>
305  */
306 #undef INIT_TIMER_AFTER_SUSPEND
307 
308 #ifdef INIT_TIMER_AFTER_SUSPEND
309 #include <linux/timex.h>
310 #include <asm/io.h>
311 #include <linux/delay.h>
312 #endif
313 
314 /*
315  * Need to poll the APM BIOS every second
316  */
317 #define APM_CHECK_TIMEOUT	(HZ)
318 
319 /*
320  * Ignore suspend events for this amount of time after a resume
321  */
322 #define DEFAULT_BOUNCE_INTERVAL	(3 * HZ)
323 
324 /*
325  * Maximum number of events stored
326  */
327 #define APM_MAX_EVENTS		20
328 
329 /*
330  * The per-file APM data
331  */
332 struct apm_user {
333 	int		magic;
334 	struct apm_user *next;
335 	unsigned int	suser: 1;
336 	unsigned int	writer: 1;
337 	unsigned int	reader: 1;
338 	unsigned int	suspend_wait: 1;
339 	int		suspend_result;
340 	int		suspends_pending;
341 	int		standbys_pending;
342 	int		suspends_read;
343 	int		standbys_read;
344 	int		event_head;
345 	int		event_tail;
346 	apm_event_t	events[APM_MAX_EVENTS];
347 };
348 
349 /*
350  * The magic number in apm_user
351  */
352 #define APM_BIOS_MAGIC		0x4101
353 
354 /*
355  * idle percentage above which bios idle calls are done
356  */
357 #ifdef CONFIG_APM_CPU_IDLE
358 #define DEFAULT_IDLE_THRESHOLD	95
359 #else
360 #define DEFAULT_IDLE_THRESHOLD	100
361 #endif
362 #define DEFAULT_IDLE_PERIOD	(100 / 3)
363 
364 static int apm_cpu_idle(struct cpuidle_device *dev,
365 			struct cpuidle_driver *drv, int index);
366 
367 static struct cpuidle_driver apm_idle_driver = {
368 	.name = "apm_idle",
369 	.owner = THIS_MODULE,
370 	.states = {
371 		{ /* entry 0 is for polling */ },
372 		{ /* entry 1 is for APM idle */
373 			.name = "APM",
374 			.desc = "APM idle",
375 			.exit_latency = 250,	/* WAG */
376 			.target_residency = 500,	/* WAG */
377 			.enter = &apm_cpu_idle
378 		},
379 	},
380 	.state_count = 2,
381 };
382 
383 static struct cpuidle_device apm_cpuidle_device;
384 
385 /*
386  * Local variables
387  */
388 __visible struct {
389 	unsigned long	offset;
390 	unsigned short	segment;
391 } apm_bios_entry;
392 static int clock_slowed;
393 static int idle_threshold __read_mostly = DEFAULT_IDLE_THRESHOLD;
394 static int idle_period __read_mostly = DEFAULT_IDLE_PERIOD;
395 static int suspends_pending;
396 static int standbys_pending;
397 static int ignore_sys_suspend;
398 static int ignore_normal_resume;
399 static int bounce_interval __read_mostly = DEFAULT_BOUNCE_INTERVAL;
400 
401 static bool debug __read_mostly;
402 static bool smp __read_mostly;
403 static int apm_disabled = -1;
404 #ifdef CONFIG_SMP
405 static bool power_off;
406 #else
407 static bool power_off = 1;
408 #endif
409 static bool realmode_power_off;
410 #ifdef CONFIG_APM_ALLOW_INTS
411 static bool allow_ints = 1;
412 #else
413 static bool allow_ints;
414 #endif
415 static bool broken_psr;
416 
417 static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
418 static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
419 static struct apm_user *user_list;
420 static DEFINE_SPINLOCK(user_list_lock);
421 static DEFINE_MUTEX(apm_mutex);
422 
423 /*
424  * Set up a segment that references the real mode segment 0x40
425  * that extends up to the end of page zero (that we have reserved).
426  * This is for buggy BIOS's that refer to (real mode) segment 0x40
427  * even though they are called in protected mode.
428  */
429 static struct desc_struct bad_bios_desc = GDT_ENTRY_INIT(0x4092,
430 			(unsigned long)__va(0x400UL), PAGE_SIZE - 0x400 - 1);
431 
432 static const char driver_version[] = "1.16ac";	/* no spaces */
433 
434 static struct task_struct *kapmd_task;
435 
436 /*
437  *	APM event names taken from the APM 1.2 specification. These are
438  *	the message codes that the BIOS uses to tell us about events
439  */
440 static const char * const apm_event_name[] = {
441 	"system standby",
442 	"system suspend",
443 	"normal resume",
444 	"critical resume",
445 	"low battery",
446 	"power status change",
447 	"update time",
448 	"critical suspend",
449 	"user standby",
450 	"user suspend",
451 	"system standby resume",
452 	"capabilities change"
453 };
454 #define NR_APM_EVENT_NAME ARRAY_SIZE(apm_event_name)
455 
456 typedef struct lookup_t {
457 	int	key;
458 	char 	*msg;
459 } lookup_t;
460 
461 /*
462  *	The BIOS returns a set of standard error codes in AX when the
463  *	carry flag is set.
464  */
465 
466 static const lookup_t error_table[] = {
467 /* N/A	{ APM_SUCCESS,		"Operation succeeded" }, */
468 	{ APM_DISABLED,		"Power management disabled" },
469 	{ APM_CONNECTED,	"Real mode interface already connected" },
470 	{ APM_NOT_CONNECTED,	"Interface not connected" },
471 	{ APM_16_CONNECTED,	"16 bit interface already connected" },
472 /* N/A	{ APM_16_UNSUPPORTED,	"16 bit interface not supported" }, */
473 	{ APM_32_CONNECTED,	"32 bit interface already connected" },
474 	{ APM_32_UNSUPPORTED,	"32 bit interface not supported" },
475 	{ APM_BAD_DEVICE,	"Unrecognized device ID" },
476 	{ APM_BAD_PARAM,	"Parameter out of range" },
477 	{ APM_NOT_ENGAGED,	"Interface not engaged" },
478 	{ APM_BAD_FUNCTION,     "Function not supported" },
479 	{ APM_RESUME_DISABLED,	"Resume timer disabled" },
480 	{ APM_BAD_STATE,	"Unable to enter requested state" },
481 /* N/A	{ APM_NO_EVENTS,	"No events pending" }, */
482 	{ APM_NO_ERROR,		"BIOS did not set a return code" },
483 	{ APM_NOT_PRESENT,	"No APM present" }
484 };
485 #define ERROR_COUNT	ARRAY_SIZE(error_table)
486 
487 /**
488  *	apm_error	-	display an APM error
489  *	@str: information string
490  *	@err: APM BIOS return code
491  *
492  *	Write a meaningful log entry to the kernel log in the event of
493  *	an APM error.  Note that this also handles (negative) kernel errors.
494  */
495 
496 static void apm_error(char *str, int err)
497 {
498 	int i;
499 
500 	for (i = 0; i < ERROR_COUNT; i++)
501 		if (error_table[i].key == err)
502 			break;
503 	if (i < ERROR_COUNT)
504 		pr_notice("%s: %s\n", str, error_table[i].msg);
505 	else if (err < 0)
506 		pr_notice("%s: linux error code %i\n", str, err);
507 	else
508 		pr_notice("%s: unknown error code %#2.2x\n",
509 		       str, err);
510 }
511 
512 /*
513  * These are the actual BIOS calls.  Depending on APM_ZERO_SEGS and
514  * apm_info.allow_ints, we are being really paranoid here!  Not only
515  * are interrupts disabled, but all the segment registers (except SS)
516  * are saved and zeroed this means that if the BIOS tries to reference
517  * any data without explicitly loading the segment registers, the kernel
518  * will fault immediately rather than have some unforeseen circumstances
519  * for the rest of the kernel.  And it will be very obvious!  :-) Doing
520  * this depends on CS referring to the same physical memory as DS so that
521  * DS can be zeroed before the call. Unfortunately, we can't do anything
522  * about the stack segment/pointer.  Also, we tell the compiler that
523  * everything could change.
524  *
525  * Also, we KNOW that for the non error case of apm_bios_call, there
526  * is no useful data returned in the low order 8 bits of eax.
527  */
528 
529 static inline unsigned long __apm_irq_save(void)
530 {
531 	unsigned long flags;
532 	local_save_flags(flags);
533 	if (apm_info.allow_ints) {
534 		if (irqs_disabled_flags(flags))
535 			local_irq_enable();
536 	} else
537 		local_irq_disable();
538 
539 	return flags;
540 }
541 
542 #define apm_irq_save(flags) \
543 	do { flags = __apm_irq_save(); } while (0)
544 
545 static inline void apm_irq_restore(unsigned long flags)
546 {
547 	if (irqs_disabled_flags(flags))
548 		local_irq_disable();
549 	else if (irqs_disabled())
550 		local_irq_enable();
551 }
552 
553 #ifdef APM_ZERO_SEGS
554 #	define APM_DECL_SEGS \
555 		unsigned int saved_fs; unsigned int saved_gs;
556 #	define APM_DO_SAVE_SEGS \
557 		savesegment(fs, saved_fs); savesegment(gs, saved_gs)
558 #	define APM_DO_RESTORE_SEGS \
559 		loadsegment(fs, saved_fs); loadsegment(gs, saved_gs)
560 #else
561 #	define APM_DECL_SEGS
562 #	define APM_DO_SAVE_SEGS
563 #	define APM_DO_RESTORE_SEGS
564 #endif
565 
566 struct apm_bios_call {
567 	u32 func;
568 	/* In and out */
569 	u32 ebx;
570 	u32 ecx;
571 	/* Out only */
572 	u32 eax;
573 	u32 edx;
574 	u32 esi;
575 
576 	/* Error: -ENOMEM, or bits 8-15 of eax */
577 	int err;
578 };
579 
580 /**
581  *	__apm_bios_call - Make an APM BIOS 32bit call
582  *	@_call: pointer to struct apm_bios_call.
583  *
584  *	Make an APM call using the 32bit protected mode interface. The
585  *	caller is responsible for knowing if APM BIOS is configured and
586  *	enabled. This call can disable interrupts for a long period of
587  *	time on some laptops.  The return value is in AH and the carry
588  *	flag is loaded into AL.  If there is an error, then the error
589  *	code is returned in AH (bits 8-15 of eax) and this function
590  *	returns non-zero.
591  *
592  *	Note: this makes the call on the current CPU.
593  */
594 static long __apm_bios_call(void *_call)
595 {
596 	APM_DECL_SEGS
597 	unsigned long		flags;
598 	int			cpu;
599 	struct desc_struct	save_desc_40;
600 	struct desc_struct	*gdt;
601 	struct apm_bios_call	*call = _call;
602 	u64			ibt;
603 
604 	cpu = get_cpu();
605 	BUG_ON(cpu != 0);
606 	gdt = get_cpu_gdt_rw(cpu);
607 	save_desc_40 = gdt[0x40 / 8];
608 	gdt[0x40 / 8] = bad_bios_desc;
609 
610 	apm_irq_save(flags);
611 	firmware_restrict_branch_speculation_start();
612 	ibt = ibt_save();
613 	APM_DO_SAVE_SEGS;
614 	apm_bios_call_asm(call->func, call->ebx, call->ecx,
615 			  &call->eax, &call->ebx, &call->ecx, &call->edx,
616 			  &call->esi);
617 	APM_DO_RESTORE_SEGS;
618 	ibt_restore(ibt);
619 	firmware_restrict_branch_speculation_end();
620 	apm_irq_restore(flags);
621 	gdt[0x40 / 8] = save_desc_40;
622 	put_cpu();
623 
624 	return call->eax & 0xff;
625 }
626 
627 /* Run __apm_bios_call or __apm_bios_call_simple on CPU 0 */
628 static int on_cpu0(long (*fn)(void *), struct apm_bios_call *call)
629 {
630 	int ret;
631 
632 	/* Don't bother with work_on_cpu in the common case, so we don't
633 	 * have to worry about OOM or overhead. */
634 	if (get_cpu() == 0) {
635 		ret = fn(call);
636 		put_cpu();
637 	} else {
638 		put_cpu();
639 		ret = work_on_cpu(0, fn, call);
640 	}
641 
642 	/* work_on_cpu can fail with -ENOMEM */
643 	if (ret < 0)
644 		call->err = ret;
645 	else
646 		call->err = (call->eax >> 8) & 0xff;
647 
648 	return ret;
649 }
650 
651 /**
652  *	apm_bios_call	-	Make an APM BIOS 32bit call (on CPU 0)
653  *	@call: the apm_bios_call registers.
654  *
655  *	If there is an error, it is returned in @call.err.
656  */
657 static int apm_bios_call(struct apm_bios_call *call)
658 {
659 	return on_cpu0(__apm_bios_call, call);
660 }
661 
662 /**
663  *	__apm_bios_call_simple - Make an APM BIOS 32bit call (on CPU 0)
664  *	@_call: pointer to struct apm_bios_call.
665  *
666  *	Make a BIOS call that returns one value only, or just status.
667  *	If there is an error, then the error code is returned in AH
668  *	(bits 8-15 of eax) and this function returns non-zero (it can
669  *	also return -ENOMEM). This is used for simpler BIOS operations.
670  *	This call may hold interrupts off for a long time on some laptops.
671  *
672  *	Note: this makes the call on the current CPU.
673  */
674 static long __apm_bios_call_simple(void *_call)
675 {
676 	u8			error;
677 	APM_DECL_SEGS
678 	unsigned long		flags;
679 	int			cpu;
680 	struct desc_struct	save_desc_40;
681 	struct desc_struct	*gdt;
682 	struct apm_bios_call	*call = _call;
683 	u64			ibt;
684 
685 	cpu = get_cpu();
686 	BUG_ON(cpu != 0);
687 	gdt = get_cpu_gdt_rw(cpu);
688 	save_desc_40 = gdt[0x40 / 8];
689 	gdt[0x40 / 8] = bad_bios_desc;
690 
691 	apm_irq_save(flags);
692 	firmware_restrict_branch_speculation_start();
693 	ibt = ibt_save();
694 	APM_DO_SAVE_SEGS;
695 	error = apm_bios_call_simple_asm(call->func, call->ebx, call->ecx,
696 					 &call->eax);
697 	APM_DO_RESTORE_SEGS;
698 	ibt_restore(ibt);
699 	firmware_restrict_branch_speculation_end();
700 	apm_irq_restore(flags);
701 	gdt[0x40 / 8] = save_desc_40;
702 	put_cpu();
703 	return error;
704 }
705 
706 /**
707  *	apm_bios_call_simple	-	make a simple APM BIOS 32bit call
708  *	@func: APM function to invoke
709  *	@ebx_in: EBX register value for BIOS call
710  *	@ecx_in: ECX register value for BIOS call
711  *	@eax: EAX register on return from the BIOS call
712  *	@err: bits
713  *
714  *	Make a BIOS call that returns one value only, or just status.
715  *	If there is an error, then the error code is returned in @err
716  *	and this function returns non-zero. This is used for simpler
717  *	BIOS operations.  This call may hold interrupts off for a long
718  *	time on some laptops.
719  */
720 static int apm_bios_call_simple(u32 func, u32 ebx_in, u32 ecx_in, u32 *eax,
721 				int *err)
722 {
723 	struct apm_bios_call call;
724 	int ret;
725 
726 	call.func = func;
727 	call.ebx = ebx_in;
728 	call.ecx = ecx_in;
729 
730 	ret = on_cpu0(__apm_bios_call_simple, &call);
731 	*eax = call.eax;
732 	*err = call.err;
733 	return ret;
734 }
735 
736 /**
737  *	apm_driver_version	-	APM driver version
738  *	@val:	loaded with the APM version on return
739  *
740  *	Retrieve the APM version supported by the BIOS. This is only
741  *	supported for APM 1.1 or higher. An error indicates APM 1.0 is
742  *	probably present.
743  *
744  *	On entry val should point to a value indicating the APM driver
745  *	version with the high byte being the major and the low byte the
746  *	minor number both in BCD
747  *
748  *	On return it will hold the BIOS revision supported in the
749  *	same format.
750  */
751 
752 static int apm_driver_version(u_short *val)
753 {
754 	u32 eax;
755 	int err;
756 
757 	if (apm_bios_call_simple(APM_FUNC_VERSION, 0, *val, &eax, &err))
758 		return err;
759 	*val = eax;
760 	return APM_SUCCESS;
761 }
762 
763 /**
764  *	apm_get_event	-	get an APM event from the BIOS
765  *	@event: pointer to the event
766  *	@info: point to the event information
767  *
768  *	The APM BIOS provides a polled information for event
769  *	reporting. The BIOS expects to be polled at least every second
770  *	when events are pending. When a message is found the caller should
771  *	poll until no more messages are present.  However, this causes
772  *	problems on some laptops where a suspend event notification is
773  *	not cleared until it is acknowledged.
774  *
775  *	Additional information is returned in the info pointer, providing
776  *	that APM 1.2 is in use. If no messages are pending the value 0x80
777  *	is returned (No power management events pending).
778  */
779 static int apm_get_event(apm_event_t *event, apm_eventinfo_t *info)
780 {
781 	struct apm_bios_call call;
782 
783 	call.func = APM_FUNC_GET_EVENT;
784 	call.ebx = call.ecx = 0;
785 
786 	if (apm_bios_call(&call))
787 		return call.err;
788 
789 	*event = call.ebx;
790 	if (apm_info.connection_version < 0x0102)
791 		*info = ~0; /* indicate info not valid */
792 	else
793 		*info = call.ecx;
794 	return APM_SUCCESS;
795 }
796 
797 /**
798  *	set_power_state	-	set the power management state
799  *	@what: which items to transition
800  *	@state: state to transition to
801  *
802  *	Request an APM change of state for one or more system devices. The
803  *	processor state must be transitioned last of all. what holds the
804  *	class of device in the upper byte and the device number (0xFF for
805  *	all) for the object to be transitioned.
806  *
807  *	The state holds the state to transition to, which may in fact
808  *	be an acceptance of a BIOS requested state change.
809  */
810 
811 static int set_power_state(u_short what, u_short state)
812 {
813 	u32 eax;
814 	int err;
815 
816 	if (apm_bios_call_simple(APM_FUNC_SET_STATE, what, state, &eax, &err))
817 		return err;
818 	return APM_SUCCESS;
819 }
820 
821 /**
822  *	set_system_power_state - set system wide power state
823  *	@state: which state to enter
824  *
825  *	Transition the entire system into a new APM power state.
826  */
827 
828 static int set_system_power_state(u_short state)
829 {
830 	return set_power_state(APM_DEVICE_ALL, state);
831 }
832 
833 /**
834  *	apm_do_idle	-	perform power saving
835  *
836  *	This function notifies the BIOS that the processor is (in the view
837  *	of the OS) idle. It returns -1 in the event that the BIOS refuses
838  *	to handle the idle request. On a success the function returns 1
839  *	if the BIOS did clock slowing or 0 otherwise.
840  */
841 
842 static int apm_do_idle(void)
843 {
844 	u32 eax;
845 	u8 ret = 0;
846 	int idled = 0;
847 	int err = 0;
848 
849 	if (!need_resched()) {
850 		idled = 1;
851 		ret = apm_bios_call_simple(APM_FUNC_IDLE, 0, 0, &eax, &err);
852 	}
853 
854 	if (!idled)
855 		return 0;
856 
857 	if (ret) {
858 		static unsigned long t;
859 
860 		/* This always fails on some SMP boards running UP kernels.
861 		 * Only report the failure the first 5 times.
862 		 */
863 		if (++t < 5) {
864 			printk(KERN_DEBUG "apm_do_idle failed (%d)\n", err);
865 			t = jiffies;
866 		}
867 		return -1;
868 	}
869 	clock_slowed = (apm_info.bios.flags & APM_IDLE_SLOWS_CLOCK) != 0;
870 	return clock_slowed;
871 }
872 
873 /**
874  *	apm_do_busy	-	inform the BIOS the CPU is busy
875  *
876  *	Request that the BIOS brings the CPU back to full performance.
877  */
878 
879 static void apm_do_busy(void)
880 {
881 	u32 dummy;
882 	int err;
883 
884 	if (clock_slowed || ALWAYS_CALL_BUSY) {
885 		(void)apm_bios_call_simple(APM_FUNC_BUSY, 0, 0, &dummy, &err);
886 		clock_slowed = 0;
887 	}
888 }
889 
890 /*
891  * If no process has really been interested in
892  * the CPU for some time, we want to call BIOS
893  * power management - we probably want
894  * to conserve power.
895  */
896 #define IDLE_CALC_LIMIT	(HZ * 100)
897 #define IDLE_LEAKY_MAX	16
898 
899 /**
900  * apm_cpu_idle		-	cpu idling for APM capable Linux
901  *
902  * This is the idling function the kernel executes when APM is available. It
903  * tries to do BIOS powermanagement based on the average system idle time.
904  * Furthermore it calls the system default idle routine.
905  */
906 
907 static int apm_cpu_idle(struct cpuidle_device *dev,
908 	struct cpuidle_driver *drv, int index)
909 {
910 	static int use_apm_idle; /* = 0 */
911 	static unsigned int last_jiffies; /* = 0 */
912 	static u64 last_stime; /* = 0 */
913 	u64 stime, utime;
914 
915 	int apm_idle_done = 0;
916 	unsigned int jiffies_since_last_check = jiffies - last_jiffies;
917 	unsigned int bucket;
918 
919 recalc:
920 	task_cputime(current, &utime, &stime);
921 	if (jiffies_since_last_check > IDLE_CALC_LIMIT) {
922 		use_apm_idle = 0;
923 	} else if (jiffies_since_last_check > idle_period) {
924 		unsigned int idle_percentage;
925 
926 		idle_percentage = nsecs_to_jiffies(stime - last_stime);
927 		idle_percentage *= 100;
928 		idle_percentage /= jiffies_since_last_check;
929 		use_apm_idle = (idle_percentage > idle_threshold);
930 		if (apm_info.forbid_idle)
931 			use_apm_idle = 0;
932 	}
933 
934 	last_jiffies = jiffies;
935 	last_stime = stime;
936 
937 	bucket = IDLE_LEAKY_MAX;
938 
939 	while (!need_resched()) {
940 		if (use_apm_idle) {
941 			unsigned int t;
942 
943 			t = jiffies;
944 			switch (apm_do_idle()) {
945 			case 0:
946 				apm_idle_done = 1;
947 				if (t != jiffies) {
948 					if (bucket) {
949 						bucket = IDLE_LEAKY_MAX;
950 						continue;
951 					}
952 				} else if (bucket) {
953 					bucket--;
954 					continue;
955 				}
956 				break;
957 			case 1:
958 				apm_idle_done = 1;
959 				break;
960 			default: /* BIOS refused */
961 				break;
962 			}
963 		}
964 		default_idle();
965 		local_irq_disable();
966 		jiffies_since_last_check = jiffies - last_jiffies;
967 		if (jiffies_since_last_check > idle_period)
968 			goto recalc;
969 	}
970 
971 	if (apm_idle_done)
972 		apm_do_busy();
973 
974 	return index;
975 }
976 
977 /**
978  *	apm_power_off	-	ask the BIOS to power off
979  *
980  *	Handle the power off sequence. This is the one piece of code we
981  *	will execute even on SMP machines. In order to deal with BIOS
982  *	bugs we support real mode APM BIOS power off calls. We also make
983  *	the SMP call on CPU0 as some systems will only honour this call
984  *	on their first cpu.
985  */
986 
987 static void apm_power_off(void)
988 {
989 	/* Some bioses don't like being called from CPU != 0 */
990 	if (apm_info.realmode_power_off) {
991 		set_cpus_allowed_ptr(current, cpumask_of(0));
992 		machine_real_restart(MRR_APM);
993 	} else {
994 		(void)set_system_power_state(APM_STATE_OFF);
995 	}
996 }
997 
998 #ifdef CONFIG_APM_DO_ENABLE
999 
1000 /**
1001  *	apm_enable_power_management - enable BIOS APM power management
1002  *	@enable: enable yes/no
1003  *
1004  *	Enable or disable the APM BIOS power services.
1005  */
1006 
1007 static int apm_enable_power_management(int enable)
1008 {
1009 	u32 eax;
1010 	int err;
1011 
1012 	if ((enable == 0) && (apm_info.bios.flags & APM_BIOS_DISENGAGED))
1013 		return APM_NOT_ENGAGED;
1014 	if (apm_bios_call_simple(APM_FUNC_ENABLE_PM, APM_DEVICE_BALL,
1015 				 enable, &eax, &err))
1016 		return err;
1017 	if (enable)
1018 		apm_info.bios.flags &= ~APM_BIOS_DISABLED;
1019 	else
1020 		apm_info.bios.flags |= APM_BIOS_DISABLED;
1021 	return APM_SUCCESS;
1022 }
1023 #endif
1024 
1025 /**
1026  *	apm_get_power_status	-	get current power state
1027  *	@status: returned status
1028  *	@bat: battery info
1029  *	@life: estimated life
1030  *
1031  *	Obtain the current power status from the APM BIOS. We return a
1032  *	status which gives the rough battery status, and current power
1033  *	source. The bat value returned give an estimate as a percentage
1034  *	of life and a status value for the battery. The estimated life
1035  *	if reported is a lifetime in seconds/minutes at current power
1036  *	consumption.
1037  */
1038 
1039 static int apm_get_power_status(u_short *status, u_short *bat, u_short *life)
1040 {
1041 	struct apm_bios_call call;
1042 
1043 	call.func = APM_FUNC_GET_STATUS;
1044 	call.ebx = APM_DEVICE_ALL;
1045 	call.ecx = 0;
1046 
1047 	if (apm_info.get_power_status_broken)
1048 		return APM_32_UNSUPPORTED;
1049 	if (apm_bios_call(&call)) {
1050 		if (!call.err)
1051 			return APM_NO_ERROR;
1052 		return call.err;
1053 	}
1054 	*status = call.ebx;
1055 	*bat = call.ecx;
1056 	if (apm_info.get_power_status_swabinminutes) {
1057 		*life = swab16((u16)call.edx);
1058 		*life |= 0x8000;
1059 	} else
1060 		*life = call.edx;
1061 	return APM_SUCCESS;
1062 }
1063 
1064 #if 0
1065 static int apm_get_battery_status(u_short which, u_short *status,
1066 				  u_short *bat, u_short *life, u_short *nbat)
1067 {
1068 	u32 eax;
1069 	u32 ebx;
1070 	u32 ecx;
1071 	u32 edx;
1072 	u32 esi;
1073 
1074 	if (apm_info.connection_version < 0x0102) {
1075 		/* pretend we only have one battery. */
1076 		if (which != 1)
1077 			return APM_BAD_DEVICE;
1078 		*nbat = 1;
1079 		return apm_get_power_status(status, bat, life);
1080 	}
1081 
1082 	if (apm_bios_call(APM_FUNC_GET_STATUS, (0x8000 | (which)), 0, &eax,
1083 			  &ebx, &ecx, &edx, &esi))
1084 		return (eax >> 8) & 0xff;
1085 	*status = ebx;
1086 	*bat = ecx;
1087 	*life = edx;
1088 	*nbat = esi;
1089 	return APM_SUCCESS;
1090 }
1091 #endif
1092 
1093 /**
1094  *	apm_engage_power_management	-	enable PM on a device
1095  *	@device: identity of device
1096  *	@enable: on/off
1097  *
1098  *	Activate or deactivate power management on either a specific device
1099  *	or the entire system (%APM_DEVICE_ALL).
1100  */
1101 
1102 static int apm_engage_power_management(u_short device, int enable)
1103 {
1104 	u32 eax;
1105 	int err;
1106 
1107 	if ((enable == 0) && (device == APM_DEVICE_ALL)
1108 	    && (apm_info.bios.flags & APM_BIOS_DISABLED))
1109 		return APM_DISABLED;
1110 	if (apm_bios_call_simple(APM_FUNC_ENGAGE_PM, device, enable,
1111 				 &eax, &err))
1112 		return err;
1113 	if (device == APM_DEVICE_ALL) {
1114 		if (enable)
1115 			apm_info.bios.flags &= ~APM_BIOS_DISENGAGED;
1116 		else
1117 			apm_info.bios.flags |= APM_BIOS_DISENGAGED;
1118 	}
1119 	return APM_SUCCESS;
1120 }
1121 
1122 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1123 
1124 /**
1125  *	apm_console_blank	-	blank the display
1126  *	@blank: on/off
1127  *
1128  *	Attempt to blank the console, firstly by blanking just video device
1129  *	zero, and if that fails (some BIOSes don't support it) then it blanks
1130  *	all video devices. Typically the BIOS will do laptop backlight and
1131  *	monitor powerdown for us.
1132  */
1133 
1134 static int apm_console_blank(int blank)
1135 {
1136 	int error = APM_NOT_ENGAGED; /* silence gcc */
1137 	int i;
1138 	u_short state;
1139 	static const u_short dev[3] = { 0x100, 0x1FF, 0x101 };
1140 
1141 	state = blank ? APM_STATE_STANDBY : APM_STATE_READY;
1142 
1143 	for (i = 0; i < ARRAY_SIZE(dev); i++) {
1144 		error = set_power_state(dev[i], state);
1145 
1146 		if ((error == APM_SUCCESS) || (error == APM_NO_ERROR))
1147 			return 1;
1148 
1149 		if (error == APM_NOT_ENGAGED)
1150 			break;
1151 	}
1152 
1153 	if (error == APM_NOT_ENGAGED) {
1154 		static int tried;
1155 		int eng_error;
1156 		if (tried++ == 0) {
1157 			eng_error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1158 			if (eng_error) {
1159 				apm_error("set display", error);
1160 				apm_error("engage interface", eng_error);
1161 				return 0;
1162 			} else
1163 				return apm_console_blank(blank);
1164 		}
1165 	}
1166 	apm_error("set display", error);
1167 	return 0;
1168 }
1169 #endif
1170 
1171 static int queue_empty(struct apm_user *as)
1172 {
1173 	return as->event_head == as->event_tail;
1174 }
1175 
1176 static apm_event_t get_queued_event(struct apm_user *as)
1177 {
1178 	if (++as->event_tail >= APM_MAX_EVENTS)
1179 		as->event_tail = 0;
1180 	return as->events[as->event_tail];
1181 }
1182 
1183 static void queue_event(apm_event_t event, struct apm_user *sender)
1184 {
1185 	struct apm_user *as;
1186 
1187 	spin_lock(&user_list_lock);
1188 	if (user_list == NULL)
1189 		goto out;
1190 	for (as = user_list; as != NULL; as = as->next) {
1191 		if ((as == sender) || (!as->reader))
1192 			continue;
1193 		if (++as->event_head >= APM_MAX_EVENTS)
1194 			as->event_head = 0;
1195 
1196 		if (as->event_head == as->event_tail) {
1197 			static int notified;
1198 
1199 			if (notified++ == 0)
1200 				pr_err("an event queue overflowed\n");
1201 			if (++as->event_tail >= APM_MAX_EVENTS)
1202 				as->event_tail = 0;
1203 		}
1204 		as->events[as->event_head] = event;
1205 		if (!as->suser || !as->writer)
1206 			continue;
1207 		switch (event) {
1208 		case APM_SYS_SUSPEND:
1209 		case APM_USER_SUSPEND:
1210 			as->suspends_pending++;
1211 			suspends_pending++;
1212 			break;
1213 
1214 		case APM_SYS_STANDBY:
1215 		case APM_USER_STANDBY:
1216 			as->standbys_pending++;
1217 			standbys_pending++;
1218 			break;
1219 		}
1220 	}
1221 	wake_up_interruptible(&apm_waitqueue);
1222 out:
1223 	spin_unlock(&user_list_lock);
1224 }
1225 
1226 static void reinit_timer(void)
1227 {
1228 #ifdef INIT_TIMER_AFTER_SUSPEND
1229 	unsigned long flags;
1230 
1231 	raw_spin_lock_irqsave(&i8253_lock, flags);
1232 	/* set the clock to HZ */
1233 	outb_p(0x34, PIT_MODE);		/* binary, mode 2, LSB/MSB, ch 0 */
1234 	udelay(10);
1235 	outb_p(LATCH & 0xff, PIT_CH0);	/* LSB */
1236 	udelay(10);
1237 	outb_p(LATCH >> 8, PIT_CH0);	/* MSB */
1238 	udelay(10);
1239 	raw_spin_unlock_irqrestore(&i8253_lock, flags);
1240 #endif
1241 }
1242 
1243 static int suspend(int vetoable)
1244 {
1245 	int err;
1246 	struct apm_user	*as;
1247 
1248 	dpm_suspend_start(PMSG_SUSPEND);
1249 	dpm_suspend_end(PMSG_SUSPEND);
1250 
1251 	local_irq_disable();
1252 	syscore_suspend();
1253 
1254 	local_irq_enable();
1255 
1256 	save_processor_state();
1257 	err = set_system_power_state(APM_STATE_SUSPEND);
1258 	ignore_normal_resume = 1;
1259 	restore_processor_state();
1260 
1261 	local_irq_disable();
1262 	reinit_timer();
1263 
1264 	if (err == APM_NO_ERROR)
1265 		err = APM_SUCCESS;
1266 	if (err != APM_SUCCESS)
1267 		apm_error("suspend", err);
1268 	err = (err == APM_SUCCESS) ? 0 : -EIO;
1269 
1270 	syscore_resume();
1271 	local_irq_enable();
1272 
1273 	dpm_resume_start(PMSG_RESUME);
1274 	dpm_resume_end(PMSG_RESUME);
1275 
1276 	queue_event(APM_NORMAL_RESUME, NULL);
1277 	spin_lock(&user_list_lock);
1278 	for (as = user_list; as != NULL; as = as->next) {
1279 		as->suspend_wait = 0;
1280 		as->suspend_result = err;
1281 	}
1282 	spin_unlock(&user_list_lock);
1283 	wake_up_interruptible(&apm_suspend_waitqueue);
1284 	return err;
1285 }
1286 
1287 static void standby(void)
1288 {
1289 	int err;
1290 
1291 	dpm_suspend_end(PMSG_SUSPEND);
1292 
1293 	local_irq_disable();
1294 	syscore_suspend();
1295 	local_irq_enable();
1296 
1297 	err = set_system_power_state(APM_STATE_STANDBY);
1298 	if ((err != APM_SUCCESS) && (err != APM_NO_ERROR))
1299 		apm_error("standby", err);
1300 
1301 	local_irq_disable();
1302 	syscore_resume();
1303 	local_irq_enable();
1304 
1305 	dpm_resume_start(PMSG_RESUME);
1306 }
1307 
1308 static apm_event_t get_event(void)
1309 {
1310 	int error;
1311 	apm_event_t event = APM_NO_EVENTS; /* silence gcc */
1312 	apm_eventinfo_t	info;
1313 
1314 	static int notified;
1315 
1316 	/* we don't use the eventinfo */
1317 	error = apm_get_event(&event, &info);
1318 	if (error == APM_SUCCESS)
1319 		return event;
1320 
1321 	if ((error != APM_NO_EVENTS) && (notified++ == 0))
1322 		apm_error("get_event", error);
1323 
1324 	return 0;
1325 }
1326 
1327 static void check_events(void)
1328 {
1329 	apm_event_t event;
1330 	static unsigned long last_resume;
1331 	static int ignore_bounce;
1332 
1333 	while ((event = get_event()) != 0) {
1334 		if (debug) {
1335 			if (event <= NR_APM_EVENT_NAME)
1336 				printk(KERN_DEBUG "apm: received %s notify\n",
1337 				       apm_event_name[event - 1]);
1338 			else
1339 				printk(KERN_DEBUG "apm: received unknown "
1340 				       "event 0x%02x\n", event);
1341 		}
1342 		if (ignore_bounce
1343 		    && (time_after(jiffies, last_resume + bounce_interval)))
1344 			ignore_bounce = 0;
1345 
1346 		switch (event) {
1347 		case APM_SYS_STANDBY:
1348 		case APM_USER_STANDBY:
1349 			queue_event(event, NULL);
1350 			if (standbys_pending <= 0)
1351 				standby();
1352 			break;
1353 
1354 		case APM_USER_SUSPEND:
1355 #ifdef CONFIG_APM_IGNORE_USER_SUSPEND
1356 			if (apm_info.connection_version > 0x100)
1357 				set_system_power_state(APM_STATE_REJECT);
1358 			break;
1359 #endif
1360 		case APM_SYS_SUSPEND:
1361 			if (ignore_bounce) {
1362 				if (apm_info.connection_version > 0x100)
1363 					set_system_power_state(APM_STATE_REJECT);
1364 				break;
1365 			}
1366 			/*
1367 			 * If we are already processing a SUSPEND,
1368 			 * then further SUSPEND events from the BIOS
1369 			 * will be ignored.  We also return here to
1370 			 * cope with the fact that the Thinkpads keep
1371 			 * sending a SUSPEND event until something else
1372 			 * happens!
1373 			 */
1374 			if (ignore_sys_suspend)
1375 				return;
1376 			ignore_sys_suspend = 1;
1377 			queue_event(event, NULL);
1378 			if (suspends_pending <= 0)
1379 				(void) suspend(1);
1380 			break;
1381 
1382 		case APM_NORMAL_RESUME:
1383 		case APM_CRITICAL_RESUME:
1384 		case APM_STANDBY_RESUME:
1385 			ignore_sys_suspend = 0;
1386 			last_resume = jiffies;
1387 			ignore_bounce = 1;
1388 			if ((event != APM_NORMAL_RESUME)
1389 			    || (ignore_normal_resume == 0)) {
1390 				dpm_resume_end(PMSG_RESUME);
1391 				queue_event(event, NULL);
1392 			}
1393 			ignore_normal_resume = 0;
1394 			break;
1395 
1396 		case APM_CAPABILITY_CHANGE:
1397 		case APM_LOW_BATTERY:
1398 		case APM_POWER_STATUS_CHANGE:
1399 			queue_event(event, NULL);
1400 			/* If needed, notify drivers here */
1401 			break;
1402 
1403 		case APM_UPDATE_TIME:
1404 			break;
1405 
1406 		case APM_CRITICAL_SUSPEND:
1407 			/*
1408 			 * We are not allowed to reject a critical suspend.
1409 			 */
1410 			(void)suspend(0);
1411 			break;
1412 		}
1413 	}
1414 }
1415 
1416 static void apm_event_handler(void)
1417 {
1418 	static int pending_count = 4;
1419 	int err;
1420 
1421 	if ((standbys_pending > 0) || (suspends_pending > 0)) {
1422 		if ((apm_info.connection_version > 0x100) &&
1423 		    (pending_count-- <= 0)) {
1424 			pending_count = 4;
1425 			if (debug)
1426 				printk(KERN_DEBUG "apm: setting state busy\n");
1427 			err = set_system_power_state(APM_STATE_BUSY);
1428 			if (err)
1429 				apm_error("busy", err);
1430 		}
1431 	} else
1432 		pending_count = 4;
1433 	check_events();
1434 }
1435 
1436 /*
1437  * This is the APM thread main loop.
1438  */
1439 
1440 static void apm_mainloop(void)
1441 {
1442 	DECLARE_WAITQUEUE(wait, current);
1443 
1444 	add_wait_queue(&apm_waitqueue, &wait);
1445 	set_current_state(TASK_INTERRUPTIBLE);
1446 	for (;;) {
1447 		schedule_timeout(APM_CHECK_TIMEOUT);
1448 		if (kthread_should_stop())
1449 			break;
1450 		/*
1451 		 * Ok, check all events, check for idle (and mark us sleeping
1452 		 * so as not to count towards the load average)..
1453 		 */
1454 		set_current_state(TASK_INTERRUPTIBLE);
1455 		apm_event_handler();
1456 	}
1457 	remove_wait_queue(&apm_waitqueue, &wait);
1458 }
1459 
1460 static int check_apm_user(struct apm_user *as, const char *func)
1461 {
1462 	if (as == NULL || as->magic != APM_BIOS_MAGIC) {
1463 		pr_err("%s passed bad filp\n", func);
1464 		return 1;
1465 	}
1466 	return 0;
1467 }
1468 
1469 static ssize_t do_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
1470 {
1471 	struct apm_user *as;
1472 	int i;
1473 	apm_event_t event;
1474 
1475 	as = fp->private_data;
1476 	if (check_apm_user(as, "read"))
1477 		return -EIO;
1478 	if ((int)count < sizeof(apm_event_t))
1479 		return -EINVAL;
1480 	if ((queue_empty(as)) && (fp->f_flags & O_NONBLOCK))
1481 		return -EAGAIN;
1482 	wait_event_interruptible(apm_waitqueue, !queue_empty(as));
1483 	i = count;
1484 	while ((i >= sizeof(event)) && !queue_empty(as)) {
1485 		event = get_queued_event(as);
1486 		if (copy_to_user(buf, &event, sizeof(event))) {
1487 			if (i < count)
1488 				break;
1489 			return -EFAULT;
1490 		}
1491 		switch (event) {
1492 		case APM_SYS_SUSPEND:
1493 		case APM_USER_SUSPEND:
1494 			as->suspends_read++;
1495 			break;
1496 
1497 		case APM_SYS_STANDBY:
1498 		case APM_USER_STANDBY:
1499 			as->standbys_read++;
1500 			break;
1501 		}
1502 		buf += sizeof(event);
1503 		i -= sizeof(event);
1504 	}
1505 	if (i < count)
1506 		return count - i;
1507 	if (signal_pending(current))
1508 		return -ERESTARTSYS;
1509 	return 0;
1510 }
1511 
1512 static __poll_t do_poll(struct file *fp, poll_table *wait)
1513 {
1514 	struct apm_user *as;
1515 
1516 	as = fp->private_data;
1517 	if (check_apm_user(as, "poll"))
1518 		return 0;
1519 	poll_wait(fp, &apm_waitqueue, wait);
1520 	if (!queue_empty(as))
1521 		return EPOLLIN | EPOLLRDNORM;
1522 	return 0;
1523 }
1524 
1525 static long do_ioctl(struct file *filp, u_int cmd, u_long arg)
1526 {
1527 	struct apm_user *as;
1528 	int ret;
1529 
1530 	as = filp->private_data;
1531 	if (check_apm_user(as, "ioctl"))
1532 		return -EIO;
1533 	if (!as->suser || !as->writer)
1534 		return -EPERM;
1535 	switch (cmd) {
1536 	case APM_IOC_STANDBY:
1537 		mutex_lock(&apm_mutex);
1538 		if (as->standbys_read > 0) {
1539 			as->standbys_read--;
1540 			as->standbys_pending--;
1541 			standbys_pending--;
1542 		} else
1543 			queue_event(APM_USER_STANDBY, as);
1544 		if (standbys_pending <= 0)
1545 			standby();
1546 		mutex_unlock(&apm_mutex);
1547 		break;
1548 	case APM_IOC_SUSPEND:
1549 		mutex_lock(&apm_mutex);
1550 		if (as->suspends_read > 0) {
1551 			as->suspends_read--;
1552 			as->suspends_pending--;
1553 			suspends_pending--;
1554 		} else
1555 			queue_event(APM_USER_SUSPEND, as);
1556 		if (suspends_pending <= 0) {
1557 			ret = suspend(1);
1558 			mutex_unlock(&apm_mutex);
1559 		} else {
1560 			as->suspend_wait = 1;
1561 			mutex_unlock(&apm_mutex);
1562 			wait_event_interruptible(apm_suspend_waitqueue,
1563 					as->suspend_wait == 0);
1564 			ret = as->suspend_result;
1565 		}
1566 		return ret;
1567 	default:
1568 		return -ENOTTY;
1569 	}
1570 	return 0;
1571 }
1572 
1573 static int do_release(struct inode *inode, struct file *filp)
1574 {
1575 	struct apm_user *as;
1576 
1577 	as = filp->private_data;
1578 	if (check_apm_user(as, "release"))
1579 		return 0;
1580 	filp->private_data = NULL;
1581 	if (as->standbys_pending > 0) {
1582 		standbys_pending -= as->standbys_pending;
1583 		if (standbys_pending <= 0)
1584 			standby();
1585 	}
1586 	if (as->suspends_pending > 0) {
1587 		suspends_pending -= as->suspends_pending;
1588 		if (suspends_pending <= 0)
1589 			(void) suspend(1);
1590 	}
1591 	spin_lock(&user_list_lock);
1592 	if (user_list == as)
1593 		user_list = as->next;
1594 	else {
1595 		struct apm_user *as1;
1596 
1597 		for (as1 = user_list;
1598 		     (as1 != NULL) && (as1->next != as);
1599 		     as1 = as1->next)
1600 			;
1601 		if (as1 == NULL)
1602 			pr_err("filp not in user list\n");
1603 		else
1604 			as1->next = as->next;
1605 	}
1606 	spin_unlock(&user_list_lock);
1607 	kfree(as);
1608 	return 0;
1609 }
1610 
1611 static int do_open(struct inode *inode, struct file *filp)
1612 {
1613 	struct apm_user *as;
1614 
1615 	as = kmalloc(sizeof(*as), GFP_KERNEL);
1616 	if (as == NULL)
1617 		return -ENOMEM;
1618 
1619 	as->magic = APM_BIOS_MAGIC;
1620 	as->event_tail = as->event_head = 0;
1621 	as->suspends_pending = as->standbys_pending = 0;
1622 	as->suspends_read = as->standbys_read = 0;
1623 	/*
1624 	 * XXX - this is a tiny bit broken, when we consider BSD
1625 	 * process accounting. If the device is opened by root, we
1626 	 * instantly flag that we used superuser privs. Who knows,
1627 	 * we might close the device immediately without doing a
1628 	 * privileged operation -- cevans
1629 	 */
1630 	as->suser = capable(CAP_SYS_ADMIN);
1631 	as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
1632 	as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
1633 	spin_lock(&user_list_lock);
1634 	as->next = user_list;
1635 	user_list = as;
1636 	spin_unlock(&user_list_lock);
1637 	filp->private_data = as;
1638 	return 0;
1639 }
1640 
1641 #ifdef CONFIG_PROC_FS
1642 static int proc_apm_show(struct seq_file *m, void *v)
1643 {
1644 	unsigned short	bx;
1645 	unsigned short	cx;
1646 	unsigned short	dx;
1647 	int		error;
1648 	unsigned short  ac_line_status = 0xff;
1649 	unsigned short  battery_status = 0xff;
1650 	unsigned short  battery_flag   = 0xff;
1651 	int		percentage     = -1;
1652 	int             time_units     = -1;
1653 	char            *units         = "?";
1654 
1655 	if ((num_online_cpus() == 1) &&
1656 	    !(error = apm_get_power_status(&bx, &cx, &dx))) {
1657 		ac_line_status = (bx >> 8) & 0xff;
1658 		battery_status = bx & 0xff;
1659 		if ((cx & 0xff) != 0xff)
1660 			percentage = cx & 0xff;
1661 
1662 		if (apm_info.connection_version > 0x100) {
1663 			battery_flag = (cx >> 8) & 0xff;
1664 			if (dx != 0xffff) {
1665 				units = (dx & 0x8000) ? "min" : "sec";
1666 				time_units = dx & 0x7fff;
1667 			}
1668 		}
1669 	}
1670 	/* Arguments, with symbols from linux/apm_bios.h.  Information is
1671 	   from the Get Power Status (0x0a) call unless otherwise noted.
1672 
1673 	   0) Linux driver version (this will change if format changes)
1674 	   1) APM BIOS Version.  Usually 1.0, 1.1 or 1.2.
1675 	   2) APM flags from APM Installation Check (0x00):
1676 	      bit 0: APM_16_BIT_SUPPORT
1677 	      bit 1: APM_32_BIT_SUPPORT
1678 	      bit 2: APM_IDLE_SLOWS_CLOCK
1679 	      bit 3: APM_BIOS_DISABLED
1680 	      bit 4: APM_BIOS_DISENGAGED
1681 	   3) AC line status
1682 	      0x00: Off-line
1683 	      0x01: On-line
1684 	      0x02: On backup power (BIOS >= 1.1 only)
1685 	      0xff: Unknown
1686 	   4) Battery status
1687 	      0x00: High
1688 	      0x01: Low
1689 	      0x02: Critical
1690 	      0x03: Charging
1691 	      0x04: Selected battery not present (BIOS >= 1.2 only)
1692 	      0xff: Unknown
1693 	   5) Battery flag
1694 	      bit 0: High
1695 	      bit 1: Low
1696 	      bit 2: Critical
1697 	      bit 3: Charging
1698 	      bit 7: No system battery
1699 	      0xff: Unknown
1700 	   6) Remaining battery life (percentage of charge):
1701 	      0-100: valid
1702 	      -1: Unknown
1703 	   7) Remaining battery life (time units):
1704 	      Number of remaining minutes or seconds
1705 	      -1: Unknown
1706 	   8) min = minutes; sec = seconds */
1707 
1708 	seq_printf(m, "%s %d.%d 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
1709 		   driver_version,
1710 		   (apm_info.bios.version >> 8) & 0xff,
1711 		   apm_info.bios.version & 0xff,
1712 		   apm_info.bios.flags,
1713 		   ac_line_status,
1714 		   battery_status,
1715 		   battery_flag,
1716 		   percentage,
1717 		   time_units,
1718 		   units);
1719 	return 0;
1720 }
1721 #endif
1722 
1723 static int apm(void *unused)
1724 {
1725 	unsigned short	bx;
1726 	unsigned short	cx;
1727 	unsigned short	dx;
1728 	int		error;
1729 	char 		*power_stat;
1730 	char 		*bat_stat;
1731 
1732 	/* 2002/08/01 - WT
1733 	 * This is to avoid random crashes at boot time during initialization
1734 	 * on SMP systems in case of "apm=power-off" mode. Seen on ASUS A7M266D.
1735 	 * Some bioses don't like being called from CPU != 0.
1736 	 * Method suggested by Ingo Molnar.
1737 	 */
1738 	set_cpus_allowed_ptr(current, cpumask_of(0));
1739 	BUG_ON(smp_processor_id() != 0);
1740 
1741 	if (apm_info.connection_version == 0) {
1742 		apm_info.connection_version = apm_info.bios.version;
1743 		if (apm_info.connection_version > 0x100) {
1744 			/*
1745 			 * We only support BIOSs up to version 1.2
1746 			 */
1747 			if (apm_info.connection_version > 0x0102)
1748 				apm_info.connection_version = 0x0102;
1749 			error = apm_driver_version(&apm_info.connection_version);
1750 			if (error != APM_SUCCESS) {
1751 				apm_error("driver version", error);
1752 				/* Fall back to an APM 1.0 connection. */
1753 				apm_info.connection_version = 0x100;
1754 			}
1755 		}
1756 	}
1757 
1758 	if (debug)
1759 		printk(KERN_INFO "apm: Connection version %d.%d\n",
1760 			(apm_info.connection_version >> 8) & 0xff,
1761 			apm_info.connection_version & 0xff);
1762 
1763 #ifdef CONFIG_APM_DO_ENABLE
1764 	if (apm_info.bios.flags & APM_BIOS_DISABLED) {
1765 		/*
1766 		 * This call causes my NEC UltraLite Versa 33/C to hang if it
1767 		 * is booted with PM disabled but not in the docking station.
1768 		 * Unfortunate ...
1769 		 */
1770 		error = apm_enable_power_management(1);
1771 		if (error) {
1772 			apm_error("enable power management", error);
1773 			return -1;
1774 		}
1775 	}
1776 #endif
1777 
1778 	if ((apm_info.bios.flags & APM_BIOS_DISENGAGED)
1779 	    && (apm_info.connection_version > 0x0100)) {
1780 		error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1781 		if (error) {
1782 			apm_error("engage power management", error);
1783 			return -1;
1784 		}
1785 	}
1786 
1787 	if (debug && (num_online_cpus() == 1 || smp)) {
1788 		error = apm_get_power_status(&bx, &cx, &dx);
1789 		if (error)
1790 			printk(KERN_INFO "apm: power status not available\n");
1791 		else {
1792 			switch ((bx >> 8) & 0xff) {
1793 			case 0:
1794 				power_stat = "off line";
1795 				break;
1796 			case 1:
1797 				power_stat = "on line";
1798 				break;
1799 			case 2:
1800 				power_stat = "on backup power";
1801 				break;
1802 			default:
1803 				power_stat = "unknown";
1804 				break;
1805 			}
1806 			switch (bx & 0xff) {
1807 			case 0:
1808 				bat_stat = "high";
1809 				break;
1810 			case 1:
1811 				bat_stat = "low";
1812 				break;
1813 			case 2:
1814 				bat_stat = "critical";
1815 				break;
1816 			case 3:
1817 				bat_stat = "charging";
1818 				break;
1819 			default:
1820 				bat_stat = "unknown";
1821 				break;
1822 			}
1823 			printk(KERN_INFO
1824 			       "apm: AC %s, battery status %s, battery life ",
1825 			       power_stat, bat_stat);
1826 			if ((cx & 0xff) == 0xff)
1827 				printk("unknown\n");
1828 			else
1829 				printk("%d%%\n", cx & 0xff);
1830 			if (apm_info.connection_version > 0x100) {
1831 				printk(KERN_INFO
1832 				       "apm: battery flag 0x%02x, battery life ",
1833 				       (cx >> 8) & 0xff);
1834 				if (dx == 0xffff)
1835 					printk("unknown\n");
1836 				else
1837 					printk("%d %s\n", dx & 0x7fff,
1838 					       (dx & 0x8000) ?
1839 					       "minutes" : "seconds");
1840 			}
1841 		}
1842 	}
1843 
1844 	/* Install our power off handler.. */
1845 	if (power_off)
1846 		pm_power_off = apm_power_off;
1847 
1848 	if (num_online_cpus() == 1 || smp) {
1849 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1850 		console_blank_hook = apm_console_blank;
1851 #endif
1852 		apm_mainloop();
1853 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1854 		console_blank_hook = NULL;
1855 #endif
1856 	}
1857 
1858 	return 0;
1859 }
1860 
1861 #ifndef MODULE
1862 static int __init apm_setup(char *str)
1863 {
1864 	int invert;
1865 
1866 	while ((str != NULL) && (*str != '\0')) {
1867 		if (strncmp(str, "off", 3) == 0)
1868 			apm_disabled = 1;
1869 		if (strncmp(str, "on", 2) == 0)
1870 			apm_disabled = 0;
1871 		if ((strncmp(str, "bounce-interval=", 16) == 0) ||
1872 		    (strncmp(str, "bounce_interval=", 16) == 0))
1873 			bounce_interval = simple_strtol(str + 16, NULL, 0);
1874 		if ((strncmp(str, "idle-threshold=", 15) == 0) ||
1875 		    (strncmp(str, "idle_threshold=", 15) == 0))
1876 			idle_threshold = simple_strtol(str + 15, NULL, 0);
1877 		if ((strncmp(str, "idle-period=", 12) == 0) ||
1878 		    (strncmp(str, "idle_period=", 12) == 0))
1879 			idle_period = simple_strtol(str + 12, NULL, 0);
1880 		invert = (strncmp(str, "no-", 3) == 0) ||
1881 			(strncmp(str, "no_", 3) == 0);
1882 		if (invert)
1883 			str += 3;
1884 		if (strncmp(str, "debug", 5) == 0)
1885 			debug = !invert;
1886 		if ((strncmp(str, "power-off", 9) == 0) ||
1887 		    (strncmp(str, "power_off", 9) == 0))
1888 			power_off = !invert;
1889 		if (strncmp(str, "smp", 3) == 0) {
1890 			smp = !invert;
1891 			idle_threshold = 100;
1892 		}
1893 		if ((strncmp(str, "allow-ints", 10) == 0) ||
1894 		    (strncmp(str, "allow_ints", 10) == 0))
1895 			apm_info.allow_ints = !invert;
1896 		if ((strncmp(str, "broken-psr", 10) == 0) ||
1897 		    (strncmp(str, "broken_psr", 10) == 0))
1898 			apm_info.get_power_status_broken = !invert;
1899 		if ((strncmp(str, "realmode-power-off", 18) == 0) ||
1900 		    (strncmp(str, "realmode_power_off", 18) == 0))
1901 			apm_info.realmode_power_off = !invert;
1902 		str = strchr(str, ',');
1903 		if (str != NULL)
1904 			str += strspn(str, ", \t");
1905 	}
1906 	return 1;
1907 }
1908 
1909 __setup("apm=", apm_setup);
1910 #endif
1911 
1912 static const struct file_operations apm_bios_fops = {
1913 	.owner		= THIS_MODULE,
1914 	.read		= do_read,
1915 	.poll		= do_poll,
1916 	.unlocked_ioctl	= do_ioctl,
1917 	.open		= do_open,
1918 	.release	= do_release,
1919 	.llseek		= noop_llseek,
1920 };
1921 
1922 static struct miscdevice apm_device = {
1923 	APM_MINOR_DEV,
1924 	"apm_bios",
1925 	&apm_bios_fops
1926 };
1927 
1928 
1929 /* Simple "print if true" callback */
1930 static int __init print_if_true(const struct dmi_system_id *d)
1931 {
1932 	printk("%s\n", d->ident);
1933 	return 0;
1934 }
1935 
1936 /*
1937  * Some Bioses enable the PS/2 mouse (touchpad) at resume, even if it was
1938  * disabled before the suspend. Linux used to get terribly confused by that.
1939  */
1940 static int __init broken_ps2_resume(const struct dmi_system_id *d)
1941 {
1942 	printk(KERN_INFO "%s machine detected. Mousepad Resume Bug "
1943 	       "workaround hopefully not needed.\n", d->ident);
1944 	return 0;
1945 }
1946 
1947 /* Some bioses have a broken protected mode poweroff and need to use realmode */
1948 static int __init set_realmode_power_off(const struct dmi_system_id *d)
1949 {
1950 	if (apm_info.realmode_power_off == 0) {
1951 		apm_info.realmode_power_off = 1;
1952 		printk(KERN_INFO "%s bios detected. "
1953 		       "Using realmode poweroff only.\n", d->ident);
1954 	}
1955 	return 0;
1956 }
1957 
1958 /* Some laptops require interrupts to be enabled during APM calls */
1959 static int __init set_apm_ints(const struct dmi_system_id *d)
1960 {
1961 	if (apm_info.allow_ints == 0) {
1962 		apm_info.allow_ints = 1;
1963 		printk(KERN_INFO "%s machine detected. "
1964 		       "Enabling interrupts during APM calls.\n", d->ident);
1965 	}
1966 	return 0;
1967 }
1968 
1969 /* Some APM bioses corrupt memory or just plain do not work */
1970 static int __init apm_is_horked(const struct dmi_system_id *d)
1971 {
1972 	if (apm_info.disabled == 0) {
1973 		apm_info.disabled = 1;
1974 		printk(KERN_INFO "%s machine detected. "
1975 		       "Disabling APM.\n", d->ident);
1976 	}
1977 	return 0;
1978 }
1979 
1980 static int __init apm_is_horked_d850md(const struct dmi_system_id *d)
1981 {
1982 	if (apm_info.disabled == 0) {
1983 		apm_info.disabled = 1;
1984 		printk(KERN_INFO "%s machine detected. "
1985 		       "Disabling APM.\n", d->ident);
1986 		printk(KERN_INFO "This bug is fixed in bios P15 which is available for\n");
1987 		printk(KERN_INFO "download from support.intel.com\n");
1988 	}
1989 	return 0;
1990 }
1991 
1992 /* Some APM bioses hang on APM idle calls */
1993 static int __init apm_likes_to_melt(const struct dmi_system_id *d)
1994 {
1995 	if (apm_info.forbid_idle == 0) {
1996 		apm_info.forbid_idle = 1;
1997 		printk(KERN_INFO "%s machine detected. "
1998 		       "Disabling APM idle calls.\n", d->ident);
1999 	}
2000 	return 0;
2001 }
2002 
2003 /*
2004  *  Check for clue free BIOS implementations who use
2005  *  the following QA technique
2006  *
2007  *      [ Write BIOS Code ]<------
2008  *               |                ^
2009  *      < Does it Compile >----N--
2010  *               |Y               ^
2011  *	< Does it Boot Win98 >-N--
2012  *               |Y
2013  *           [Ship It]
2014  *
2015  *	Phoenix A04  08/24/2000 is known bad (Dell Inspiron 5000e)
2016  *	Phoenix A07  09/29/2000 is known good (Dell Inspiron 5000)
2017  */
2018 static int __init broken_apm_power(const struct dmi_system_id *d)
2019 {
2020 	apm_info.get_power_status_broken = 1;
2021 	printk(KERN_WARNING "BIOS strings suggest APM bugs, "
2022 	       "disabling power status reporting.\n");
2023 	return 0;
2024 }
2025 
2026 /*
2027  * This bios swaps the APM minute reporting bytes over (Many sony laptops
2028  * have this problem).
2029  */
2030 static int __init swab_apm_power_in_minutes(const struct dmi_system_id *d)
2031 {
2032 	apm_info.get_power_status_swabinminutes = 1;
2033 	printk(KERN_WARNING "BIOS strings suggest APM reports battery life "
2034 	       "in minutes and wrong byte order.\n");
2035 	return 0;
2036 }
2037 
2038 static const struct dmi_system_id apm_dmi_table[] __initconst = {
2039 	{
2040 		print_if_true,
2041 		KERN_WARNING "IBM T23 - BIOS 1.03b+ and controller firmware 1.02+ may be needed for Linux APM.",
2042 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
2043 			DMI_MATCH(DMI_BIOS_VERSION, "1AET38WW (1.01b)"), },
2044 	},
2045 	{	/* Handle problems with APM on the C600 */
2046 		broken_ps2_resume, "Dell Latitude C600",
2047 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
2048 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C600"), },
2049 	},
2050 	{	/* Allow interrupts during suspend on Dell Latitude laptops*/
2051 		set_apm_ints, "Dell Latitude",
2052 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2053 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C510"), }
2054 	},
2055 	{	/* APM crashes */
2056 		apm_is_horked, "Dell Inspiron 2500",
2057 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2058 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2059 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2060 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2061 	},
2062 	{	/* Allow interrupts during suspend on Dell Inspiron laptops*/
2063 		set_apm_ints, "Dell Inspiron", {
2064 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2065 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 4000"), },
2066 	},
2067 	{	/* Handle problems with APM on Inspiron 5000e */
2068 		broken_apm_power, "Dell Inspiron 5000e",
2069 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2070 			DMI_MATCH(DMI_BIOS_VERSION, "A04"),
2071 			DMI_MATCH(DMI_BIOS_DATE, "08/24/2000"), },
2072 	},
2073 	{	/* Handle problems with APM on Inspiron 2500 */
2074 		broken_apm_power, "Dell Inspiron 2500",
2075 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2076 			DMI_MATCH(DMI_BIOS_VERSION, "A12"),
2077 			DMI_MATCH(DMI_BIOS_DATE, "02/04/2002"), },
2078 	},
2079 	{	/* APM crashes */
2080 		apm_is_horked, "Dell Dimension 4100",
2081 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2082 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"),
2083 			DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2084 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2085 	},
2086 	{	/* Allow interrupts during suspend on Compaq Laptops*/
2087 		set_apm_ints, "Compaq 12XL125",
2088 		{	DMI_MATCH(DMI_SYS_VENDOR, "Compaq"),
2089 			DMI_MATCH(DMI_PRODUCT_NAME, "Compaq PC"),
2090 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2091 			DMI_MATCH(DMI_BIOS_VERSION, "4.06"), },
2092 	},
2093 	{	/* Allow interrupts during APM or the clock goes slow */
2094 		set_apm_ints, "ASUSTeK",
2095 		{	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
2096 			DMI_MATCH(DMI_PRODUCT_NAME, "L8400K series Notebook PC"), },
2097 	},
2098 	{	/* APM blows on shutdown */
2099 		apm_is_horked, "ABIT KX7-333[R]",
2100 		{	DMI_MATCH(DMI_BOARD_VENDOR, "ABIT"),
2101 			DMI_MATCH(DMI_BOARD_NAME, "VT8367-8233A (KX7-333[R])"), },
2102 	},
2103 	{	/* APM crashes */
2104 		apm_is_horked, "Trigem Delhi3",
2105 		{	DMI_MATCH(DMI_SYS_VENDOR, "TriGem Computer, Inc"),
2106 			DMI_MATCH(DMI_PRODUCT_NAME, "Delhi3"), },
2107 	},
2108 	{	/* APM crashes */
2109 		apm_is_horked, "Fujitsu-Siemens",
2110 		{	DMI_MATCH(DMI_BIOS_VENDOR, "hoenix/FUJITSU SIEMENS"),
2111 			DMI_MATCH(DMI_BIOS_VERSION, "Version1.01"), },
2112 	},
2113 	{	/* APM crashes */
2114 		apm_is_horked_d850md, "Intel D850MD",
2115 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2116 			DMI_MATCH(DMI_BIOS_VERSION, "MV85010A.86A.0016.P07.0201251536"), },
2117 	},
2118 	{	/* APM crashes */
2119 		apm_is_horked, "Intel D810EMO",
2120 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2121 			DMI_MATCH(DMI_BIOS_VERSION, "MO81010A.86A.0008.P04.0004170800"), },
2122 	},
2123 	{	/* APM crashes */
2124 		apm_is_horked, "Dell XPS-Z",
2125 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2126 			DMI_MATCH(DMI_BIOS_VERSION, "A11"),
2127 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"), },
2128 	},
2129 	{	/* APM crashes */
2130 		apm_is_horked, "Sharp PC-PJ/AX",
2131 		{	DMI_MATCH(DMI_SYS_VENDOR, "SHARP"),
2132 			DMI_MATCH(DMI_PRODUCT_NAME, "PC-PJ/AX"),
2133 			DMI_MATCH(DMI_BIOS_VENDOR, "SystemSoft"),
2134 			DMI_MATCH(DMI_BIOS_VERSION, "Version R2.08"), },
2135 	},
2136 	{	/* APM crashes */
2137 		apm_is_horked, "Dell Inspiron 2500",
2138 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2139 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2140 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2141 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2142 	},
2143 	{	/* APM idle hangs */
2144 		apm_likes_to_melt, "Jabil AMD",
2145 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2146 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP06"), },
2147 	},
2148 	{	/* APM idle hangs */
2149 		apm_likes_to_melt, "AMI Bios",
2150 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2151 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP05"), },
2152 	},
2153 	{	/* Handle problems with APM on Sony Vaio PCG-N505X(DE) */
2154 		swab_apm_power_in_minutes, "Sony VAIO",
2155 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2156 			DMI_MATCH(DMI_BIOS_VERSION, "R0206H"),
2157 			DMI_MATCH(DMI_BIOS_DATE, "08/23/99"), },
2158 	},
2159 	{	/* Handle problems with APM on Sony Vaio PCG-N505VX */
2160 		swab_apm_power_in_minutes, "Sony VAIO",
2161 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2162 			DMI_MATCH(DMI_BIOS_VERSION, "W2K06H0"),
2163 			DMI_MATCH(DMI_BIOS_DATE, "02/03/00"), },
2164 	},
2165 	{	/* Handle problems with APM on Sony Vaio PCG-XG29 */
2166 		swab_apm_power_in_minutes, "Sony VAIO",
2167 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2168 			DMI_MATCH(DMI_BIOS_VERSION, "R0117A0"),
2169 			DMI_MATCH(DMI_BIOS_DATE, "04/25/00"), },
2170 	},
2171 	{	/* Handle problems with APM on Sony Vaio PCG-Z600NE */
2172 		swab_apm_power_in_minutes, "Sony VAIO",
2173 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2174 			DMI_MATCH(DMI_BIOS_VERSION, "R0121Z1"),
2175 			DMI_MATCH(DMI_BIOS_DATE, "05/11/00"), },
2176 	},
2177 	{	/* Handle problems with APM on Sony Vaio PCG-Z600NE */
2178 		swab_apm_power_in_minutes, "Sony VAIO",
2179 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2180 			DMI_MATCH(DMI_BIOS_VERSION, "WME01Z1"),
2181 			DMI_MATCH(DMI_BIOS_DATE, "08/11/00"), },
2182 	},
2183 	{	/* Handle problems with APM on Sony Vaio PCG-Z600LEK(DE) */
2184 		swab_apm_power_in_minutes, "Sony VAIO",
2185 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2186 			DMI_MATCH(DMI_BIOS_VERSION, "R0206Z3"),
2187 			DMI_MATCH(DMI_BIOS_DATE, "12/25/00"), },
2188 	},
2189 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS */
2190 		swab_apm_power_in_minutes, "Sony VAIO",
2191 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2192 			DMI_MATCH(DMI_BIOS_VERSION, "R0203D0"),
2193 			DMI_MATCH(DMI_BIOS_DATE, "05/12/00"), },
2194 	},
2195 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS */
2196 		swab_apm_power_in_minutes, "Sony VAIO",
2197 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2198 			DMI_MATCH(DMI_BIOS_VERSION, "R0203Z3"),
2199 			DMI_MATCH(DMI_BIOS_DATE, "08/25/00"), },
2200 	},
2201 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS (with updated BIOS) */
2202 		swab_apm_power_in_minutes, "Sony VAIO",
2203 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2204 			DMI_MATCH(DMI_BIOS_VERSION, "R0209Z3"),
2205 			DMI_MATCH(DMI_BIOS_DATE, "05/12/01"), },
2206 	},
2207 	{	/* Handle problems with APM on Sony Vaio PCG-F104K */
2208 		swab_apm_power_in_minutes, "Sony VAIO",
2209 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2210 			DMI_MATCH(DMI_BIOS_VERSION, "R0204K2"),
2211 			DMI_MATCH(DMI_BIOS_DATE, "08/28/00"), },
2212 	},
2213 
2214 	{	/* Handle problems with APM on Sony Vaio PCG-C1VN/C1VE */
2215 		swab_apm_power_in_minutes, "Sony VAIO",
2216 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2217 			DMI_MATCH(DMI_BIOS_VERSION, "R0208P1"),
2218 			DMI_MATCH(DMI_BIOS_DATE, "11/09/00"), },
2219 	},
2220 	{	/* Handle problems with APM on Sony Vaio PCG-C1VE */
2221 		swab_apm_power_in_minutes, "Sony VAIO",
2222 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2223 			DMI_MATCH(DMI_BIOS_VERSION, "R0204P1"),
2224 			DMI_MATCH(DMI_BIOS_DATE, "09/12/00"), },
2225 	},
2226 	{	/* Handle problems with APM on Sony Vaio PCG-C1VE */
2227 		swab_apm_power_in_minutes, "Sony VAIO",
2228 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2229 			DMI_MATCH(DMI_BIOS_VERSION, "WXPO1Z3"),
2230 			DMI_MATCH(DMI_BIOS_DATE, "10/26/01"), },
2231 	},
2232 	{	/* broken PM poweroff bios */
2233 		set_realmode_power_off, "Award Software v4.60 PGMA",
2234 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Award Software International, Inc."),
2235 			DMI_MATCH(DMI_BIOS_VERSION, "4.60 PGMA"),
2236 			DMI_MATCH(DMI_BIOS_DATE, "134526184"), },
2237 	},
2238 
2239 	/* Generic per vendor APM settings  */
2240 
2241 	{	/* Allow interrupts during suspend on IBM laptops */
2242 		set_apm_ints, "IBM",
2243 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"), },
2244 	},
2245 
2246 	{ }
2247 };
2248 
2249 /*
2250  * Just start the APM thread. We do NOT want to do APM BIOS
2251  * calls from anything but the APM thread, if for no other reason
2252  * than the fact that we don't trust the APM BIOS. This way,
2253  * most common APM BIOS problems that lead to protection errors
2254  * etc will have at least some level of being contained...
2255  *
2256  * In short, if something bad happens, at least we have a choice
2257  * of just killing the apm thread..
2258  */
2259 static int __init apm_init(void)
2260 {
2261 	struct desc_struct *gdt;
2262 	int err;
2263 
2264 	dmi_check_system(apm_dmi_table);
2265 
2266 	if (apm_info.bios.version == 0 || machine_is_olpc()) {
2267 		printk(KERN_INFO "apm: BIOS not found.\n");
2268 		return -ENODEV;
2269 	}
2270 	printk(KERN_INFO
2271 	       "apm: BIOS version %d.%d Flags 0x%02x (Driver version %s)\n",
2272 	       ((apm_info.bios.version >> 8) & 0xff),
2273 	       (apm_info.bios.version & 0xff),
2274 	       apm_info.bios.flags,
2275 	       driver_version);
2276 	if ((apm_info.bios.flags & APM_32_BIT_SUPPORT) == 0) {
2277 		printk(KERN_INFO "apm: no 32 bit BIOS support\n");
2278 		return -ENODEV;
2279 	}
2280 
2281 	if (allow_ints)
2282 		apm_info.allow_ints = 1;
2283 	if (broken_psr)
2284 		apm_info.get_power_status_broken = 1;
2285 	if (realmode_power_off)
2286 		apm_info.realmode_power_off = 1;
2287 	/* User can override, but default is to trust DMI */
2288 	if (apm_disabled != -1)
2289 		apm_info.disabled = apm_disabled;
2290 
2291 	/*
2292 	 * Fix for the Compaq Contura 3/25c which reports BIOS version 0.1
2293 	 * but is reportedly a 1.0 BIOS.
2294 	 */
2295 	if (apm_info.bios.version == 0x001)
2296 		apm_info.bios.version = 0x100;
2297 
2298 	/* BIOS < 1.2 doesn't set cseg_16_len */
2299 	if (apm_info.bios.version < 0x102)
2300 		apm_info.bios.cseg_16_len = 0; /* 64k */
2301 
2302 	if (debug) {
2303 		printk(KERN_INFO "apm: entry %x:%x cseg16 %x dseg %x",
2304 			apm_info.bios.cseg, apm_info.bios.offset,
2305 			apm_info.bios.cseg_16, apm_info.bios.dseg);
2306 		if (apm_info.bios.version > 0x100)
2307 			printk(" cseg len %x, dseg len %x",
2308 				apm_info.bios.cseg_len,
2309 				apm_info.bios.dseg_len);
2310 		if (apm_info.bios.version > 0x101)
2311 			printk(" cseg16 len %x", apm_info.bios.cseg_16_len);
2312 		printk("\n");
2313 	}
2314 
2315 	if (apm_info.disabled) {
2316 		pr_notice("disabled on user request.\n");
2317 		return -ENODEV;
2318 	}
2319 	if ((num_online_cpus() > 1) && !power_off && !smp) {
2320 		pr_notice("disabled - APM is not SMP safe.\n");
2321 		apm_info.disabled = 1;
2322 		return -ENODEV;
2323 	}
2324 	if (!acpi_disabled) {
2325 		pr_notice("overridden by ACPI.\n");
2326 		apm_info.disabled = 1;
2327 		return -ENODEV;
2328 	}
2329 
2330 	/*
2331 	 * Set up the long jump entry point to the APM BIOS, which is called
2332 	 * from inline assembly.
2333 	 */
2334 	apm_bios_entry.offset = apm_info.bios.offset;
2335 	apm_bios_entry.segment = APM_CS;
2336 
2337 	/*
2338 	 * The APM 1.1 BIOS is supposed to provide limit information that it
2339 	 * recognizes.  Many machines do this correctly, but many others do
2340 	 * not restrict themselves to their claimed limit.  When this happens,
2341 	 * they will cause a segmentation violation in the kernel at boot time.
2342 	 * Most BIOS's, however, will respect a 64k limit, so we use that.
2343 	 *
2344 	 * Note we only set APM segments on CPU zero, since we pin the APM
2345 	 * code to that CPU.
2346 	 */
2347 	gdt = get_cpu_gdt_rw(0);
2348 	set_desc_base(&gdt[APM_CS >> 3],
2349 		 (unsigned long)__va((unsigned long)apm_info.bios.cseg << 4));
2350 	set_desc_base(&gdt[APM_CS_16 >> 3],
2351 		 (unsigned long)__va((unsigned long)apm_info.bios.cseg_16 << 4));
2352 	set_desc_base(&gdt[APM_DS >> 3],
2353 		 (unsigned long)__va((unsigned long)apm_info.bios.dseg << 4));
2354 
2355 	proc_create_single("apm", 0, NULL, proc_apm_show);
2356 
2357 	kapmd_task = kthread_create(apm, NULL, "kapmd");
2358 	if (IS_ERR(kapmd_task)) {
2359 		pr_err("disabled - Unable to start kernel thread\n");
2360 		err = PTR_ERR(kapmd_task);
2361 		kapmd_task = NULL;
2362 		remove_proc_entry("apm", NULL);
2363 		return err;
2364 	}
2365 	wake_up_process(kapmd_task);
2366 
2367 	if (num_online_cpus() > 1 && !smp) {
2368 		printk(KERN_NOTICE
2369 		       "apm: disabled - APM is not SMP safe (power off active).\n");
2370 		return 0;
2371 	}
2372 
2373 	/*
2374 	 * Note we don't actually care if the misc_device cannot be registered.
2375 	 * this driver can do its job without it, even if userspace can't
2376 	 * control it.  just log the error
2377 	 */
2378 	if (misc_register(&apm_device))
2379 		printk(KERN_WARNING "apm: Could not register misc device.\n");
2380 
2381 	if (HZ != 100)
2382 		idle_period = (idle_period * HZ) / 100;
2383 	if (idle_threshold < 100) {
2384 		cpuidle_poll_state_init(&apm_idle_driver);
2385 		if (!cpuidle_register_driver(&apm_idle_driver))
2386 			if (cpuidle_register_device(&apm_cpuidle_device))
2387 				cpuidle_unregister_driver(&apm_idle_driver);
2388 	}
2389 
2390 	return 0;
2391 }
2392 
2393 static void __exit apm_exit(void)
2394 {
2395 	int error;
2396 
2397 	cpuidle_unregister_device(&apm_cpuidle_device);
2398 	cpuidle_unregister_driver(&apm_idle_driver);
2399 
2400 	if (((apm_info.bios.flags & APM_BIOS_DISENGAGED) == 0)
2401 	    && (apm_info.connection_version > 0x0100)) {
2402 		error = apm_engage_power_management(APM_DEVICE_ALL, 0);
2403 		if (error)
2404 			apm_error("disengage power management", error);
2405 	}
2406 	misc_deregister(&apm_device);
2407 	remove_proc_entry("apm", NULL);
2408 	if (power_off)
2409 		pm_power_off = NULL;
2410 	if (kapmd_task) {
2411 		kthread_stop(kapmd_task);
2412 		kapmd_task = NULL;
2413 	}
2414 }
2415 
2416 module_init(apm_init);
2417 module_exit(apm_exit);
2418 
2419 MODULE_AUTHOR("Stephen Rothwell");
2420 MODULE_DESCRIPTION("Advanced Power Management");
2421 MODULE_LICENSE("GPL");
2422 module_param(debug, bool, 0644);
2423 MODULE_PARM_DESC(debug, "Enable debug mode");
2424 module_param(power_off, bool, 0444);
2425 MODULE_PARM_DESC(power_off, "Enable power off");
2426 module_param(bounce_interval, int, 0444);
2427 MODULE_PARM_DESC(bounce_interval,
2428 		"Set the number of ticks to ignore suspend bounces");
2429 module_param(allow_ints, bool, 0444);
2430 MODULE_PARM_DESC(allow_ints, "Allow interrupts during BIOS calls");
2431 module_param(broken_psr, bool, 0444);
2432 MODULE_PARM_DESC(broken_psr, "BIOS has a broken GetPowerStatus call");
2433 module_param(realmode_power_off, bool, 0444);
2434 MODULE_PARM_DESC(realmode_power_off,
2435 		"Switch to real mode before powering off");
2436 module_param(idle_threshold, int, 0444);
2437 MODULE_PARM_DESC(idle_threshold,
2438 	"System idle percentage above which to make APM BIOS idle calls");
2439 module_param(idle_period, int, 0444);
2440 MODULE_PARM_DESC(idle_period,
2441 	"Period (in sec/100) over which to calculate the idle percentage");
2442 module_param(smp, bool, 0444);
2443 MODULE_PARM_DESC(smp,
2444 	"Set this to enable APM use on an SMP platform. Use with caution on older systems");
2445 MODULE_ALIAS_MISCDEV(APM_MINOR_DEV);
2446