xref: /openbmc/linux/arch/x86/kernel/apm_32.c (revision 7dd65feb)
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 complier/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@suse.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 via anonymous ftp from
193  * ftp://ftp.intel.com/pub/IAL/software_specs/apmv11.doc.  It is also
194  * available from Microsoft by calling 206.882.8080.]
195  *
196  * APM 1.2 Reference:
197  *   Intel Corporation, Microsoft Corporation. Advanced Power Management
198  *   (APM) BIOS Interface Specification, Revision 1.2, February 1996.
199  *
200  * [This document is available from Microsoft at:
201  *    http://www.microsoft.com/whdc/archive/amp_12.mspx]
202  */
203 
204 #include <linux/module.h>
205 
206 #include <linux/poll.h>
207 #include <linux/types.h>
208 #include <linux/stddef.h>
209 #include <linux/timer.h>
210 #include <linux/fcntl.h>
211 #include <linux/slab.h>
212 #include <linux/stat.h>
213 #include <linux/proc_fs.h>
214 #include <linux/seq_file.h>
215 #include <linux/miscdevice.h>
216 #include <linux/apm_bios.h>
217 #include <linux/init.h>
218 #include <linux/time.h>
219 #include <linux/sched.h>
220 #include <linux/pm.h>
221 #include <linux/capability.h>
222 #include <linux/device.h>
223 #include <linux/kernel.h>
224 #include <linux/freezer.h>
225 #include <linux/smp.h>
226 #include <linux/dmi.h>
227 #include <linux/suspend.h>
228 #include <linux/kthread.h>
229 #include <linux/jiffies.h>
230 
231 #include <asm/system.h>
232 #include <asm/uaccess.h>
233 #include <asm/desc.h>
234 #include <asm/i8253.h>
235 #include <asm/olpc.h>
236 #include <asm/paravirt.h>
237 #include <asm/reboot.h>
238 
239 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
240 extern int (*console_blank_hook)(int);
241 #endif
242 
243 /*
244  * The apm_bios device is one of the misc char devices.
245  * This is its minor number.
246  */
247 #define	APM_MINOR_DEV	134
248 
249 /*
250  * See Documentation/Config.help for the configuration options.
251  *
252  * Various options can be changed at boot time as follows:
253  * (We allow underscores for compatibility with the modules code)
254  *	apm=on/off			enable/disable APM
255  *	    [no-]allow[-_]ints		allow interrupts during BIOS calls
256  *	    [no-]broken[-_]psr		BIOS has a broken GetPowerStatus call
257  *	    [no-]realmode[-_]power[-_]off	switch to real mode before
258  *	    					powering off
259  *	    [no-]debug			log some debugging messages
260  *	    [no-]power[-_]off		power off on shutdown
261  *	    [no-]smp			Use apm even on an SMP box
262  *	    bounce[-_]interval=<n>	number of ticks to ignore suspend
263  *	    				bounces
264  *          idle[-_]threshold=<n>       System idle percentage above which to
265  *                                      make APM BIOS idle calls. Set it to
266  *                                      100 to disable.
267  *          idle[-_]period=<n>          Period (in 1/100s of a second) over
268  *                                      which the idle percentage is
269  *                                      calculated.
270  */
271 
272 /* KNOWN PROBLEM MACHINES:
273  *
274  * U: TI 4000M TravelMate: BIOS is *NOT* APM compliant
275  *                         [Confirmed by TI representative]
276  * ?: ACER 486DX4/75: uses dseg 0040, in violation of APM specification
277  *                    [Confirmed by BIOS disassembly]
278  *                    [This may work now ...]
279  * P: Toshiba 1950S: battery life information only gets updated after resume
280  * P: Midwest Micro Soundbook Elite DX2/66 monochrome: screen blanking
281  * 	broken in BIOS [Reported by Garst R. Reese <reese@isn.net>]
282  * ?: AcerNote-950: oops on reading /proc/apm - workaround is a WIP
283  * 	Neale Banks <neale@lowendale.com.au> December 2000
284  *
285  * Legend: U = unusable with APM patches
286  *         P = partially usable with APM patches
287  */
288 
289 /*
290  * Define as 1 to make the driver always call the APM BIOS busy
291  * routine even if the clock was not reported as slowed by the
292  * idle routine.  Otherwise, define as 0.
293  */
294 #define ALWAYS_CALL_BUSY   1
295 
296 /*
297  * Define to make the APM BIOS calls zero all data segment registers (so
298  * that an incorrect BIOS implementation will cause a kernel panic if it
299  * tries to write to arbitrary memory).
300  */
301 #define APM_ZERO_SEGS
302 
303 #include <asm/apm.h>
304 
305 /*
306  * Define to re-initialize the interrupt 0 timer to 100 Hz after a suspend.
307  * This patched by Chad Miller <cmiller@surfsouth.com>, original code by
308  * David Chen <chen@ctpa04.mit.edu>
309  */
310 #undef INIT_TIMER_AFTER_SUSPEND
311 
312 #ifdef INIT_TIMER_AFTER_SUSPEND
313 #include <linux/timex.h>
314 #include <asm/io.h>
315 #include <linux/delay.h>
316 #endif
317 
318 /*
319  * Need to poll the APM BIOS every second
320  */
321 #define APM_CHECK_TIMEOUT	(HZ)
322 
323 /*
324  * Ignore suspend events for this amount of time after a resume
325  */
326 #define DEFAULT_BOUNCE_INTERVAL	(3 * HZ)
327 
328 /*
329  * Maximum number of events stored
330  */
331 #define APM_MAX_EVENTS		20
332 
333 /*
334  * The per-file APM data
335  */
336 struct apm_user {
337 	int		magic;
338 	struct apm_user *next;
339 	unsigned int	suser: 1;
340 	unsigned int	writer: 1;
341 	unsigned int	reader: 1;
342 	unsigned int	suspend_wait: 1;
343 	int		suspend_result;
344 	int		suspends_pending;
345 	int		standbys_pending;
346 	int		suspends_read;
347 	int		standbys_read;
348 	int		event_head;
349 	int		event_tail;
350 	apm_event_t	events[APM_MAX_EVENTS];
351 };
352 
353 /*
354  * The magic number in apm_user
355  */
356 #define APM_BIOS_MAGIC		0x4101
357 
358 /*
359  * idle percentage above which bios idle calls are done
360  */
361 #ifdef CONFIG_APM_CPU_IDLE
362 #define DEFAULT_IDLE_THRESHOLD	95
363 #else
364 #define DEFAULT_IDLE_THRESHOLD	100
365 #endif
366 #define DEFAULT_IDLE_PERIOD	(100 / 3)
367 
368 /*
369  * Local variables
370  */
371 static struct {
372 	unsigned long	offset;
373 	unsigned short	segment;
374 } apm_bios_entry;
375 static int clock_slowed;
376 static int idle_threshold __read_mostly = DEFAULT_IDLE_THRESHOLD;
377 static int idle_period __read_mostly = DEFAULT_IDLE_PERIOD;
378 static int set_pm_idle;
379 static int suspends_pending;
380 static int standbys_pending;
381 static int ignore_sys_suspend;
382 static int ignore_normal_resume;
383 static int bounce_interval __read_mostly = DEFAULT_BOUNCE_INTERVAL;
384 
385 static int debug __read_mostly;
386 static int smp __read_mostly;
387 static int apm_disabled = -1;
388 #ifdef CONFIG_SMP
389 static int power_off;
390 #else
391 static int power_off = 1;
392 #endif
393 static int realmode_power_off;
394 #ifdef CONFIG_APM_ALLOW_INTS
395 static int allow_ints = 1;
396 #else
397 static int allow_ints;
398 #endif
399 static int broken_psr;
400 
401 static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
402 static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
403 static struct apm_user *user_list;
404 static DEFINE_SPINLOCK(user_list_lock);
405 static DEFINE_MUTEX(apm_mutex);
406 
407 /*
408  * Set up a segment that references the real mode segment 0x40
409  * that extends up to the end of page zero (that we have reserved).
410  * This is for buggy BIOS's that refer to (real mode) segment 0x40
411  * even though they are called in protected mode.
412  */
413 static struct desc_struct bad_bios_desc = GDT_ENTRY_INIT(0x4092,
414 			(unsigned long)__va(0x400UL), PAGE_SIZE - 0x400 - 1);
415 
416 static const char driver_version[] = "1.16ac";	/* no spaces */
417 
418 static struct task_struct *kapmd_task;
419 
420 /*
421  *	APM event names taken from the APM 1.2 specification. These are
422  *	the message codes that the BIOS uses to tell us about events
423  */
424 static const char * const apm_event_name[] = {
425 	"system standby",
426 	"system suspend",
427 	"normal resume",
428 	"critical resume",
429 	"low battery",
430 	"power status change",
431 	"update time",
432 	"critical suspend",
433 	"user standby",
434 	"user suspend",
435 	"system standby resume",
436 	"capabilities change"
437 };
438 #define NR_APM_EVENT_NAME ARRAY_SIZE(apm_event_name)
439 
440 typedef struct lookup_t {
441 	int	key;
442 	char 	*msg;
443 } lookup_t;
444 
445 /*
446  *	The BIOS returns a set of standard error codes in AX when the
447  *	carry flag is set.
448  */
449 
450 static const lookup_t error_table[] = {
451 /* N/A	{ APM_SUCCESS,		"Operation succeeded" }, */
452 	{ APM_DISABLED,		"Power management disabled" },
453 	{ APM_CONNECTED,	"Real mode interface already connected" },
454 	{ APM_NOT_CONNECTED,	"Interface not connected" },
455 	{ APM_16_CONNECTED,	"16 bit interface already connected" },
456 /* N/A	{ APM_16_UNSUPPORTED,	"16 bit interface not supported" }, */
457 	{ APM_32_CONNECTED,	"32 bit interface already connected" },
458 	{ APM_32_UNSUPPORTED,	"32 bit interface not supported" },
459 	{ APM_BAD_DEVICE,	"Unrecognized device ID" },
460 	{ APM_BAD_PARAM,	"Parameter out of range" },
461 	{ APM_NOT_ENGAGED,	"Interface not engaged" },
462 	{ APM_BAD_FUNCTION,     "Function not supported" },
463 	{ APM_RESUME_DISABLED,	"Resume timer disabled" },
464 	{ APM_BAD_STATE,	"Unable to enter requested state" },
465 /* N/A	{ APM_NO_EVENTS,	"No events pending" }, */
466 	{ APM_NO_ERROR,		"BIOS did not set a return code" },
467 	{ APM_NOT_PRESENT,	"No APM present" }
468 };
469 #define ERROR_COUNT	ARRAY_SIZE(error_table)
470 
471 /**
472  *	apm_error	-	display an APM error
473  *	@str: information string
474  *	@err: APM BIOS return code
475  *
476  *	Write a meaningful log entry to the kernel log in the event of
477  *	an APM error.  Note that this also handles (negative) kernel errors.
478  */
479 
480 static void apm_error(char *str, int err)
481 {
482 	int i;
483 
484 	for (i = 0; i < ERROR_COUNT; i++)
485 		if (error_table[i].key == err)
486 			break;
487 	if (i < ERROR_COUNT)
488 		printk(KERN_NOTICE "apm: %s: %s\n", str, error_table[i].msg);
489 	else if (err < 0)
490 		printk(KERN_NOTICE "apm: %s: linux error code %i\n", str, err);
491 	else
492 		printk(KERN_NOTICE "apm: %s: unknown error code %#2.2x\n",
493 		       str, err);
494 }
495 
496 /*
497  * These are the actual BIOS calls.  Depending on APM_ZERO_SEGS and
498  * apm_info.allow_ints, we are being really paranoid here!  Not only
499  * are interrupts disabled, but all the segment registers (except SS)
500  * are saved and zeroed this means that if the BIOS tries to reference
501  * any data without explicitly loading the segment registers, the kernel
502  * will fault immediately rather than have some unforeseen circumstances
503  * for the rest of the kernel.  And it will be very obvious!  :-) Doing
504  * this depends on CS referring to the same physical memory as DS so that
505  * DS can be zeroed before the call. Unfortunately, we can't do anything
506  * about the stack segment/pointer.  Also, we tell the compiler that
507  * everything could change.
508  *
509  * Also, we KNOW that for the non error case of apm_bios_call, there
510  * is no useful data returned in the low order 8 bits of eax.
511  */
512 
513 static inline unsigned long __apm_irq_save(void)
514 {
515 	unsigned long flags;
516 	local_save_flags(flags);
517 	if (apm_info.allow_ints) {
518 		if (irqs_disabled_flags(flags))
519 			local_irq_enable();
520 	} else
521 		local_irq_disable();
522 
523 	return flags;
524 }
525 
526 #define apm_irq_save(flags) \
527 	do { flags = __apm_irq_save(); } while (0)
528 
529 static inline void apm_irq_restore(unsigned long flags)
530 {
531 	if (irqs_disabled_flags(flags))
532 		local_irq_disable();
533 	else if (irqs_disabled())
534 		local_irq_enable();
535 }
536 
537 #ifdef APM_ZERO_SEGS
538 #	define APM_DECL_SEGS \
539 		unsigned int saved_fs; unsigned int saved_gs;
540 #	define APM_DO_SAVE_SEGS \
541 		savesegment(fs, saved_fs); savesegment(gs, saved_gs)
542 #	define APM_DO_RESTORE_SEGS \
543 		loadsegment(fs, saved_fs); loadsegment(gs, saved_gs)
544 #else
545 #	define APM_DECL_SEGS
546 #	define APM_DO_SAVE_SEGS
547 #	define APM_DO_RESTORE_SEGS
548 #endif
549 
550 struct apm_bios_call {
551 	u32 func;
552 	/* In and out */
553 	u32 ebx;
554 	u32 ecx;
555 	/* Out only */
556 	u32 eax;
557 	u32 edx;
558 	u32 esi;
559 
560 	/* Error: -ENOMEM, or bits 8-15 of eax */
561 	int err;
562 };
563 
564 /**
565  *	__apm_bios_call - Make an APM BIOS 32bit call
566  *	@_call: pointer to struct apm_bios_call.
567  *
568  *	Make an APM call using the 32bit protected mode interface. The
569  *	caller is responsible for knowing if APM BIOS is configured and
570  *	enabled. This call can disable interrupts for a long period of
571  *	time on some laptops.  The return value is in AH and the carry
572  *	flag is loaded into AL.  If there is an error, then the error
573  *	code is returned in AH (bits 8-15 of eax) and this function
574  *	returns non-zero.
575  *
576  *	Note: this makes the call on the current CPU.
577  */
578 static long __apm_bios_call(void *_call)
579 {
580 	APM_DECL_SEGS
581 	unsigned long		flags;
582 	int			cpu;
583 	struct desc_struct	save_desc_40;
584 	struct desc_struct	*gdt;
585 	struct apm_bios_call	*call = _call;
586 
587 	cpu = get_cpu();
588 	BUG_ON(cpu != 0);
589 	gdt = get_cpu_gdt_table(cpu);
590 	save_desc_40 = gdt[0x40 / 8];
591 	gdt[0x40 / 8] = bad_bios_desc;
592 
593 	apm_irq_save(flags);
594 	APM_DO_SAVE_SEGS;
595 	apm_bios_call_asm(call->func, call->ebx, call->ecx,
596 			  &call->eax, &call->ebx, &call->ecx, &call->edx,
597 			  &call->esi);
598 	APM_DO_RESTORE_SEGS;
599 	apm_irq_restore(flags);
600 	gdt[0x40 / 8] = save_desc_40;
601 	put_cpu();
602 
603 	return call->eax & 0xff;
604 }
605 
606 /* Run __apm_bios_call or __apm_bios_call_simple on CPU 0 */
607 static int on_cpu0(long (*fn)(void *), struct apm_bios_call *call)
608 {
609 	int ret;
610 
611 	/* Don't bother with work_on_cpu in the common case, so we don't
612 	 * have to worry about OOM or overhead. */
613 	if (get_cpu() == 0) {
614 		ret = fn(call);
615 		put_cpu();
616 	} else {
617 		put_cpu();
618 		ret = work_on_cpu(0, fn, call);
619 	}
620 
621 	/* work_on_cpu can fail with -ENOMEM */
622 	if (ret < 0)
623 		call->err = ret;
624 	else
625 		call->err = (call->eax >> 8) & 0xff;
626 
627 	return ret;
628 }
629 
630 /**
631  *	apm_bios_call	-	Make an APM BIOS 32bit call (on CPU 0)
632  *	@call: the apm_bios_call registers.
633  *
634  *	If there is an error, it is returned in @call.err.
635  */
636 static int apm_bios_call(struct apm_bios_call *call)
637 {
638 	return on_cpu0(__apm_bios_call, call);
639 }
640 
641 /**
642  *	__apm_bios_call_simple - Make an APM BIOS 32bit call (on CPU 0)
643  *	@_call: pointer to struct apm_bios_call.
644  *
645  *	Make a BIOS call that returns one value only, or just status.
646  *	If there is an error, then the error code is returned in AH
647  *	(bits 8-15 of eax) and this function returns non-zero (it can
648  *	also return -ENOMEM). This is used for simpler BIOS operations.
649  *	This call may hold interrupts off for a long time on some laptops.
650  *
651  *	Note: this makes the call on the current CPU.
652  */
653 static long __apm_bios_call_simple(void *_call)
654 {
655 	u8			error;
656 	APM_DECL_SEGS
657 	unsigned long		flags;
658 	int			cpu;
659 	struct desc_struct	save_desc_40;
660 	struct desc_struct	*gdt;
661 	struct apm_bios_call	*call = _call;
662 
663 	cpu = get_cpu();
664 	BUG_ON(cpu != 0);
665 	gdt = get_cpu_gdt_table(cpu);
666 	save_desc_40 = gdt[0x40 / 8];
667 	gdt[0x40 / 8] = bad_bios_desc;
668 
669 	apm_irq_save(flags);
670 	APM_DO_SAVE_SEGS;
671 	error = apm_bios_call_simple_asm(call->func, call->ebx, call->ecx,
672 					 &call->eax);
673 	APM_DO_RESTORE_SEGS;
674 	apm_irq_restore(flags);
675 	gdt[0x40 / 8] = save_desc_40;
676 	put_cpu();
677 	return error;
678 }
679 
680 /**
681  *	apm_bios_call_simple	-	make a simple APM BIOS 32bit call
682  *	@func: APM function to invoke
683  *	@ebx_in: EBX register value for BIOS call
684  *	@ecx_in: ECX register value for BIOS call
685  *	@eax: EAX register on return from the BIOS call
686  *	@err: bits
687  *
688  *	Make a BIOS call that returns one value only, or just status.
689  *	If there is an error, then the error code is returned in @err
690  *	and this function returns non-zero. This is used for simpler
691  *	BIOS operations.  This call may hold interrupts off for a long
692  *	time on some laptops.
693  */
694 static int apm_bios_call_simple(u32 func, u32 ebx_in, u32 ecx_in, u32 *eax,
695 				int *err)
696 {
697 	struct apm_bios_call call;
698 	int ret;
699 
700 	call.func = func;
701 	call.ebx = ebx_in;
702 	call.ecx = ecx_in;
703 
704 	ret = on_cpu0(__apm_bios_call_simple, &call);
705 	*eax = call.eax;
706 	*err = call.err;
707 	return ret;
708 }
709 
710 /**
711  *	apm_driver_version	-	APM driver version
712  *	@val:	loaded with the APM version on return
713  *
714  *	Retrieve the APM version supported by the BIOS. This is only
715  *	supported for APM 1.1 or higher. An error indicates APM 1.0 is
716  *	probably present.
717  *
718  *	On entry val should point to a value indicating the APM driver
719  *	version with the high byte being the major and the low byte the
720  *	minor number both in BCD
721  *
722  *	On return it will hold the BIOS revision supported in the
723  *	same format.
724  */
725 
726 static int apm_driver_version(u_short *val)
727 {
728 	u32 eax;
729 	int err;
730 
731 	if (apm_bios_call_simple(APM_FUNC_VERSION, 0, *val, &eax, &err))
732 		return err;
733 	*val = eax;
734 	return APM_SUCCESS;
735 }
736 
737 /**
738  *	apm_get_event	-	get an APM event from the BIOS
739  *	@event: pointer to the event
740  *	@info: point to the event information
741  *
742  *	The APM BIOS provides a polled information for event
743  *	reporting. The BIOS expects to be polled at least every second
744  *	when events are pending. When a message is found the caller should
745  *	poll until no more messages are present.  However, this causes
746  *	problems on some laptops where a suspend event notification is
747  *	not cleared until it is acknowledged.
748  *
749  *	Additional information is returned in the info pointer, providing
750  *	that APM 1.2 is in use. If no messges are pending the value 0x80
751  *	is returned (No power management events pending).
752  */
753 static int apm_get_event(apm_event_t *event, apm_eventinfo_t *info)
754 {
755 	struct apm_bios_call call;
756 
757 	call.func = APM_FUNC_GET_EVENT;
758 	call.ebx = call.ecx = 0;
759 
760 	if (apm_bios_call(&call))
761 		return call.err;
762 
763 	*event = call.ebx;
764 	if (apm_info.connection_version < 0x0102)
765 		*info = ~0; /* indicate info not valid */
766 	else
767 		*info = call.ecx;
768 	return APM_SUCCESS;
769 }
770 
771 /**
772  *	set_power_state	-	set the power management state
773  *	@what: which items to transition
774  *	@state: state to transition to
775  *
776  *	Request an APM change of state for one or more system devices. The
777  *	processor state must be transitioned last of all. what holds the
778  *	class of device in the upper byte and the device number (0xFF for
779  *	all) for the object to be transitioned.
780  *
781  *	The state holds the state to transition to, which may in fact
782  *	be an acceptance of a BIOS requested state change.
783  */
784 
785 static int set_power_state(u_short what, u_short state)
786 {
787 	u32 eax;
788 	int err;
789 
790 	if (apm_bios_call_simple(APM_FUNC_SET_STATE, what, state, &eax, &err))
791 		return err;
792 	return APM_SUCCESS;
793 }
794 
795 /**
796  *	set_system_power_state - set system wide power state
797  *	@state: which state to enter
798  *
799  *	Transition the entire system into a new APM power state.
800  */
801 
802 static int set_system_power_state(u_short state)
803 {
804 	return set_power_state(APM_DEVICE_ALL, state);
805 }
806 
807 /**
808  *	apm_do_idle	-	perform power saving
809  *
810  *	This function notifies the BIOS that the processor is (in the view
811  *	of the OS) idle. It returns -1 in the event that the BIOS refuses
812  *	to handle the idle request. On a success the function returns 1
813  *	if the BIOS did clock slowing or 0 otherwise.
814  */
815 
816 static int apm_do_idle(void)
817 {
818 	u32 eax;
819 	u8 ret = 0;
820 	int idled = 0;
821 	int polling;
822 	int err = 0;
823 
824 	polling = !!(current_thread_info()->status & TS_POLLING);
825 	if (polling) {
826 		current_thread_info()->status &= ~TS_POLLING;
827 		/*
828 		 * TS_POLLING-cleared state must be visible before we
829 		 * test NEED_RESCHED:
830 		 */
831 		smp_mb();
832 	}
833 	if (!need_resched()) {
834 		idled = 1;
835 		ret = apm_bios_call_simple(APM_FUNC_IDLE, 0, 0, &eax, &err);
836 	}
837 	if (polling)
838 		current_thread_info()->status |= TS_POLLING;
839 
840 	if (!idled)
841 		return 0;
842 
843 	if (ret) {
844 		static unsigned long t;
845 
846 		/* This always fails on some SMP boards running UP kernels.
847 		 * Only report the failure the first 5 times.
848 		 */
849 		if (++t < 5) {
850 			printk(KERN_DEBUG "apm_do_idle failed (%d)\n", err);
851 			t = jiffies;
852 		}
853 		return -1;
854 	}
855 	clock_slowed = (apm_info.bios.flags & APM_IDLE_SLOWS_CLOCK) != 0;
856 	return clock_slowed;
857 }
858 
859 /**
860  *	apm_do_busy	-	inform the BIOS the CPU is busy
861  *
862  *	Request that the BIOS brings the CPU back to full performance.
863  */
864 
865 static void apm_do_busy(void)
866 {
867 	u32 dummy;
868 	int err;
869 
870 	if (clock_slowed || ALWAYS_CALL_BUSY) {
871 		(void)apm_bios_call_simple(APM_FUNC_BUSY, 0, 0, &dummy, &err);
872 		clock_slowed = 0;
873 	}
874 }
875 
876 /*
877  * If no process has really been interested in
878  * the CPU for some time, we want to call BIOS
879  * power management - we probably want
880  * to conserve power.
881  */
882 #define IDLE_CALC_LIMIT	(HZ * 100)
883 #define IDLE_LEAKY_MAX	16
884 
885 static void (*original_pm_idle)(void) __read_mostly;
886 
887 /**
888  * apm_cpu_idle		-	cpu idling for APM capable Linux
889  *
890  * This is the idling function the kernel executes when APM is available. It
891  * tries to do BIOS powermanagement based on the average system idle time.
892  * Furthermore it calls the system default idle routine.
893  */
894 
895 static void apm_cpu_idle(void)
896 {
897 	static int use_apm_idle; /* = 0 */
898 	static unsigned int last_jiffies; /* = 0 */
899 	static unsigned int last_stime; /* = 0 */
900 
901 	int apm_idle_done = 0;
902 	unsigned int jiffies_since_last_check = jiffies - last_jiffies;
903 	unsigned int bucket;
904 
905 recalc:
906 	if (jiffies_since_last_check > IDLE_CALC_LIMIT) {
907 		use_apm_idle = 0;
908 		last_jiffies = jiffies;
909 		last_stime = current->stime;
910 	} else if (jiffies_since_last_check > idle_period) {
911 		unsigned int idle_percentage;
912 
913 		idle_percentage = current->stime - last_stime;
914 		idle_percentage *= 100;
915 		idle_percentage /= jiffies_since_last_check;
916 		use_apm_idle = (idle_percentage > idle_threshold);
917 		if (apm_info.forbid_idle)
918 			use_apm_idle = 0;
919 		last_jiffies = jiffies;
920 		last_stime = current->stime;
921 	}
922 
923 	bucket = IDLE_LEAKY_MAX;
924 
925 	while (!need_resched()) {
926 		if (use_apm_idle) {
927 			unsigned int t;
928 
929 			t = jiffies;
930 			switch (apm_do_idle()) {
931 			case 0:
932 				apm_idle_done = 1;
933 				if (t != jiffies) {
934 					if (bucket) {
935 						bucket = IDLE_LEAKY_MAX;
936 						continue;
937 					}
938 				} else if (bucket) {
939 					bucket--;
940 					continue;
941 				}
942 				break;
943 			case 1:
944 				apm_idle_done = 1;
945 				break;
946 			default: /* BIOS refused */
947 				break;
948 			}
949 		}
950 		if (original_pm_idle)
951 			original_pm_idle();
952 		else
953 			default_idle();
954 		local_irq_disable();
955 		jiffies_since_last_check = jiffies - last_jiffies;
956 		if (jiffies_since_last_check > idle_period)
957 			goto recalc;
958 	}
959 
960 	if (apm_idle_done)
961 		apm_do_busy();
962 
963 	local_irq_enable();
964 }
965 
966 /**
967  *	apm_power_off	-	ask the BIOS to power off
968  *
969  *	Handle the power off sequence. This is the one piece of code we
970  *	will execute even on SMP machines. In order to deal with BIOS
971  *	bugs we support real mode APM BIOS power off calls. We also make
972  *	the SMP call on CPU0 as some systems will only honour this call
973  *	on their first cpu.
974  */
975 
976 static void apm_power_off(void)
977 {
978 	unsigned char po_bios_call[] = {
979 		0xb8, 0x00, 0x10,	/* movw  $0x1000,ax  */
980 		0x8e, 0xd0,		/* movw  ax,ss       */
981 		0xbc, 0x00, 0xf0,	/* movw  $0xf000,sp  */
982 		0xb8, 0x07, 0x53,	/* movw  $0x5307,ax  */
983 		0xbb, 0x01, 0x00,	/* movw  $0x0001,bx  */
984 		0xb9, 0x03, 0x00,	/* movw  $0x0003,cx  */
985 		0xcd, 0x15		/* int   $0x15       */
986 	};
987 
988 	/* Some bioses don't like being called from CPU != 0 */
989 	if (apm_info.realmode_power_off) {
990 		set_cpus_allowed_ptr(current, cpumask_of(0));
991 		machine_real_restart(po_bios_call, sizeof(po_bios_call));
992 	} else {
993 		(void)set_system_power_state(APM_STATE_OFF);
994 	}
995 }
996 
997 #ifdef CONFIG_APM_DO_ENABLE
998 
999 /**
1000  *	apm_enable_power_management - enable BIOS APM power management
1001  *	@enable: enable yes/no
1002  *
1003  *	Enable or disable the APM BIOS power services.
1004  */
1005 
1006 static int apm_enable_power_management(int enable)
1007 {
1008 	u32 eax;
1009 	int err;
1010 
1011 	if ((enable == 0) && (apm_info.bios.flags & APM_BIOS_DISENGAGED))
1012 		return APM_NOT_ENGAGED;
1013 	if (apm_bios_call_simple(APM_FUNC_ENABLE_PM, APM_DEVICE_BALL,
1014 				 enable, &eax, &err))
1015 		return err;
1016 	if (enable)
1017 		apm_info.bios.flags &= ~APM_BIOS_DISABLED;
1018 	else
1019 		apm_info.bios.flags |= APM_BIOS_DISABLED;
1020 	return APM_SUCCESS;
1021 }
1022 #endif
1023 
1024 /**
1025  *	apm_get_power_status	-	get current power state
1026  *	@status: returned status
1027  *	@bat: battery info
1028  *	@life: estimated life
1029  *
1030  *	Obtain the current power status from the APM BIOS. We return a
1031  *	status which gives the rough battery status, and current power
1032  *	source. The bat value returned give an estimate as a percentage
1033  *	of life and a status value for the battery. The estimated life
1034  *	if reported is a lifetime in secodnds/minutes at current powwer
1035  *	consumption.
1036  */
1037 
1038 static int apm_get_power_status(u_short *status, u_short *bat, u_short *life)
1039 {
1040 	struct apm_bios_call call;
1041 
1042 	call.func = APM_FUNC_GET_STATUS;
1043 	call.ebx = APM_DEVICE_ALL;
1044 	call.ecx = 0;
1045 
1046 	if (apm_info.get_power_status_broken)
1047 		return APM_32_UNSUPPORTED;
1048 	if (apm_bios_call(&call))
1049 		return call.err;
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 deactive 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 			    printk(KERN_ERR "apm: 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 	spin_lock_irqsave(&i8253_lock, flags);
1228 	/* set the clock to HZ */
1229 	outb_pit(0x34, PIT_MODE);		/* binary, mode 2, LSB/MSB, ch 0 */
1230 	udelay(10);
1231 	outb_pit(LATCH & 0xff, PIT_CH0);	/* LSB */
1232 	udelay(10);
1233 	outb_pit(LATCH >> 8, PIT_CH0);	/* MSB */
1234 	udelay(10);
1235 	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 
1246 	dpm_suspend_noirq(PMSG_SUSPEND);
1247 
1248 	local_irq_disable();
1249 	sysdev_suspend(PMSG_SUSPEND);
1250 
1251 	local_irq_enable();
1252 
1253 	save_processor_state();
1254 	err = set_system_power_state(APM_STATE_SUSPEND);
1255 	ignore_normal_resume = 1;
1256 	restore_processor_state();
1257 
1258 	local_irq_disable();
1259 	reinit_timer();
1260 
1261 	if (err == APM_NO_ERROR)
1262 		err = APM_SUCCESS;
1263 	if (err != APM_SUCCESS)
1264 		apm_error("suspend", err);
1265 	err = (err == APM_SUCCESS) ? 0 : -EIO;
1266 
1267 	sysdev_resume();
1268 	local_irq_enable();
1269 
1270 	dpm_resume_noirq(PMSG_RESUME);
1271 
1272 	dpm_resume_end(PMSG_RESUME);
1273 	queue_event(APM_NORMAL_RESUME, NULL);
1274 	spin_lock(&user_list_lock);
1275 	for (as = user_list; as != NULL; as = as->next) {
1276 		as->suspend_wait = 0;
1277 		as->suspend_result = err;
1278 	}
1279 	spin_unlock(&user_list_lock);
1280 	wake_up_interruptible(&apm_suspend_waitqueue);
1281 	return err;
1282 }
1283 
1284 static void standby(void)
1285 {
1286 	int err;
1287 
1288 	dpm_suspend_noirq(PMSG_SUSPEND);
1289 
1290 	local_irq_disable();
1291 	sysdev_suspend(PMSG_SUSPEND);
1292 	local_irq_enable();
1293 
1294 	err = set_system_power_state(APM_STATE_STANDBY);
1295 	if ((err != APM_SUCCESS) && (err != APM_NO_ERROR))
1296 		apm_error("standby", err);
1297 
1298 	local_irq_disable();
1299 	sysdev_resume();
1300 	local_irq_enable();
1301 
1302 	dpm_resume_noirq(PMSG_RESUME);
1303 }
1304 
1305 static apm_event_t get_event(void)
1306 {
1307 	int error;
1308 	apm_event_t event = APM_NO_EVENTS; /* silence gcc */
1309 	apm_eventinfo_t	info;
1310 
1311 	static int notified;
1312 
1313 	/* we don't use the eventinfo */
1314 	error = apm_get_event(&event, &info);
1315 	if (error == APM_SUCCESS)
1316 		return event;
1317 
1318 	if ((error != APM_NO_EVENTS) && (notified++ == 0))
1319 		apm_error("get_event", error);
1320 
1321 	return 0;
1322 }
1323 
1324 static void check_events(void)
1325 {
1326 	apm_event_t event;
1327 	static unsigned long last_resume;
1328 	static int ignore_bounce;
1329 
1330 	while ((event = get_event()) != 0) {
1331 		if (debug) {
1332 			if (event <= NR_APM_EVENT_NAME)
1333 				printk(KERN_DEBUG "apm: received %s notify\n",
1334 				       apm_event_name[event - 1]);
1335 			else
1336 				printk(KERN_DEBUG "apm: received unknown "
1337 				       "event 0x%02x\n", event);
1338 		}
1339 		if (ignore_bounce
1340 		    && (time_after(jiffies, last_resume + bounce_interval)))
1341 			ignore_bounce = 0;
1342 
1343 		switch (event) {
1344 		case APM_SYS_STANDBY:
1345 		case APM_USER_STANDBY:
1346 			queue_event(event, NULL);
1347 			if (standbys_pending <= 0)
1348 				standby();
1349 			break;
1350 
1351 		case APM_USER_SUSPEND:
1352 #ifdef CONFIG_APM_IGNORE_USER_SUSPEND
1353 			if (apm_info.connection_version > 0x100)
1354 				set_system_power_state(APM_STATE_REJECT);
1355 			break;
1356 #endif
1357 		case APM_SYS_SUSPEND:
1358 			if (ignore_bounce) {
1359 				if (apm_info.connection_version > 0x100)
1360 					set_system_power_state(APM_STATE_REJECT);
1361 				break;
1362 			}
1363 			/*
1364 			 * If we are already processing a SUSPEND,
1365 			 * then further SUSPEND events from the BIOS
1366 			 * will be ignored.  We also return here to
1367 			 * cope with the fact that the Thinkpads keep
1368 			 * sending a SUSPEND event until something else
1369 			 * happens!
1370 			 */
1371 			if (ignore_sys_suspend)
1372 				return;
1373 			ignore_sys_suspend = 1;
1374 			queue_event(event, NULL);
1375 			if (suspends_pending <= 0)
1376 				(void) suspend(1);
1377 			break;
1378 
1379 		case APM_NORMAL_RESUME:
1380 		case APM_CRITICAL_RESUME:
1381 		case APM_STANDBY_RESUME:
1382 			ignore_sys_suspend = 0;
1383 			last_resume = jiffies;
1384 			ignore_bounce = 1;
1385 			if ((event != APM_NORMAL_RESUME)
1386 			    || (ignore_normal_resume == 0)) {
1387 				dpm_resume_end(PMSG_RESUME);
1388 				queue_event(event, NULL);
1389 			}
1390 			ignore_normal_resume = 0;
1391 			break;
1392 
1393 		case APM_CAPABILITY_CHANGE:
1394 		case APM_LOW_BATTERY:
1395 		case APM_POWER_STATUS_CHANGE:
1396 			queue_event(event, NULL);
1397 			/* If needed, notify drivers here */
1398 			break;
1399 
1400 		case APM_UPDATE_TIME:
1401 			break;
1402 
1403 		case APM_CRITICAL_SUSPEND:
1404 			/*
1405 			 * We are not allowed to reject a critical suspend.
1406 			 */
1407 			(void)suspend(0);
1408 			break;
1409 		}
1410 	}
1411 }
1412 
1413 static void apm_event_handler(void)
1414 {
1415 	static int pending_count = 4;
1416 	int err;
1417 
1418 	if ((standbys_pending > 0) || (suspends_pending > 0)) {
1419 		if ((apm_info.connection_version > 0x100) &&
1420 		    (pending_count-- <= 0)) {
1421 			pending_count = 4;
1422 			if (debug)
1423 				printk(KERN_DEBUG "apm: setting state busy\n");
1424 			err = set_system_power_state(APM_STATE_BUSY);
1425 			if (err)
1426 				apm_error("busy", err);
1427 		}
1428 	} else
1429 		pending_count = 4;
1430 	check_events();
1431 }
1432 
1433 /*
1434  * This is the APM thread main loop.
1435  */
1436 
1437 static void apm_mainloop(void)
1438 {
1439 	DECLARE_WAITQUEUE(wait, current);
1440 
1441 	add_wait_queue(&apm_waitqueue, &wait);
1442 	set_current_state(TASK_INTERRUPTIBLE);
1443 	for (;;) {
1444 		schedule_timeout(APM_CHECK_TIMEOUT);
1445 		if (kthread_should_stop())
1446 			break;
1447 		/*
1448 		 * Ok, check all events, check for idle (and mark us sleeping
1449 		 * so as not to count towards the load average)..
1450 		 */
1451 		set_current_state(TASK_INTERRUPTIBLE);
1452 		apm_event_handler();
1453 	}
1454 	remove_wait_queue(&apm_waitqueue, &wait);
1455 }
1456 
1457 static int check_apm_user(struct apm_user *as, const char *func)
1458 {
1459 	if (as == NULL || as->magic != APM_BIOS_MAGIC) {
1460 		printk(KERN_ERR "apm: %s passed bad filp\n", func);
1461 		return 1;
1462 	}
1463 	return 0;
1464 }
1465 
1466 static ssize_t do_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
1467 {
1468 	struct apm_user *as;
1469 	int i;
1470 	apm_event_t event;
1471 
1472 	as = fp->private_data;
1473 	if (check_apm_user(as, "read"))
1474 		return -EIO;
1475 	if ((int)count < sizeof(apm_event_t))
1476 		return -EINVAL;
1477 	if ((queue_empty(as)) && (fp->f_flags & O_NONBLOCK))
1478 		return -EAGAIN;
1479 	wait_event_interruptible(apm_waitqueue, !queue_empty(as));
1480 	i = count;
1481 	while ((i >= sizeof(event)) && !queue_empty(as)) {
1482 		event = get_queued_event(as);
1483 		if (copy_to_user(buf, &event, sizeof(event))) {
1484 			if (i < count)
1485 				break;
1486 			return -EFAULT;
1487 		}
1488 		switch (event) {
1489 		case APM_SYS_SUSPEND:
1490 		case APM_USER_SUSPEND:
1491 			as->suspends_read++;
1492 			break;
1493 
1494 		case APM_SYS_STANDBY:
1495 		case APM_USER_STANDBY:
1496 			as->standbys_read++;
1497 			break;
1498 		}
1499 		buf += sizeof(event);
1500 		i -= sizeof(event);
1501 	}
1502 	if (i < count)
1503 		return count - i;
1504 	if (signal_pending(current))
1505 		return -ERESTARTSYS;
1506 	return 0;
1507 }
1508 
1509 static unsigned int do_poll(struct file *fp, poll_table *wait)
1510 {
1511 	struct apm_user *as;
1512 
1513 	as = fp->private_data;
1514 	if (check_apm_user(as, "poll"))
1515 		return 0;
1516 	poll_wait(fp, &apm_waitqueue, wait);
1517 	if (!queue_empty(as))
1518 		return POLLIN | POLLRDNORM;
1519 	return 0;
1520 }
1521 
1522 static long do_ioctl(struct file *filp, u_int cmd, u_long arg)
1523 {
1524 	struct apm_user *as;
1525 	int ret;
1526 
1527 	as = filp->private_data;
1528 	if (check_apm_user(as, "ioctl"))
1529 		return -EIO;
1530 	if (!as->suser || !as->writer)
1531 		return -EPERM;
1532 	switch (cmd) {
1533 	case APM_IOC_STANDBY:
1534 		mutex_lock(&apm_mutex);
1535 		if (as->standbys_read > 0) {
1536 			as->standbys_read--;
1537 			as->standbys_pending--;
1538 			standbys_pending--;
1539 		} else
1540 			queue_event(APM_USER_STANDBY, as);
1541 		if (standbys_pending <= 0)
1542 			standby();
1543 		mutex_unlock(&apm_mutex);
1544 		break;
1545 	case APM_IOC_SUSPEND:
1546 		mutex_lock(&apm_mutex);
1547 		if (as->suspends_read > 0) {
1548 			as->suspends_read--;
1549 			as->suspends_pending--;
1550 			suspends_pending--;
1551 		} else
1552 			queue_event(APM_USER_SUSPEND, as);
1553 		if (suspends_pending <= 0) {
1554 			ret = suspend(1);
1555 			mutex_unlock(&apm_mutex);
1556 		} else {
1557 			as->suspend_wait = 1;
1558 			mutex_unlock(&apm_mutex);
1559 			wait_event_interruptible(apm_suspend_waitqueue,
1560 					as->suspend_wait == 0);
1561 			ret = as->suspend_result;
1562 		}
1563 		return ret;
1564 	default:
1565 		return -ENOTTY;
1566 	}
1567 	return 0;
1568 }
1569 
1570 static int do_release(struct inode *inode, struct file *filp)
1571 {
1572 	struct apm_user *as;
1573 
1574 	as = filp->private_data;
1575 	if (check_apm_user(as, "release"))
1576 		return 0;
1577 	filp->private_data = NULL;
1578 	if (as->standbys_pending > 0) {
1579 		standbys_pending -= as->standbys_pending;
1580 		if (standbys_pending <= 0)
1581 			standby();
1582 	}
1583 	if (as->suspends_pending > 0) {
1584 		suspends_pending -= as->suspends_pending;
1585 		if (suspends_pending <= 0)
1586 			(void) suspend(1);
1587 	}
1588 	spin_lock(&user_list_lock);
1589 	if (user_list == as)
1590 		user_list = as->next;
1591 	else {
1592 		struct apm_user *as1;
1593 
1594 		for (as1 = user_list;
1595 		     (as1 != NULL) && (as1->next != as);
1596 		     as1 = as1->next)
1597 			;
1598 		if (as1 == NULL)
1599 			printk(KERN_ERR "apm: filp not in user list\n");
1600 		else
1601 			as1->next = as->next;
1602 	}
1603 	spin_unlock(&user_list_lock);
1604 	kfree(as);
1605 	return 0;
1606 }
1607 
1608 static int do_open(struct inode *inode, struct file *filp)
1609 {
1610 	struct apm_user *as;
1611 
1612 	as = kmalloc(sizeof(*as), GFP_KERNEL);
1613 	if (as == NULL) {
1614 		printk(KERN_ERR "apm: cannot allocate struct of size %d bytes\n",
1615 		       sizeof(*as));
1616 		return -ENOMEM;
1617 	}
1618 	as->magic = APM_BIOS_MAGIC;
1619 	as->event_tail = as->event_head = 0;
1620 	as->suspends_pending = as->standbys_pending = 0;
1621 	as->suspends_read = as->standbys_read = 0;
1622 	/*
1623 	 * XXX - this is a tiny bit broken, when we consider BSD
1624 	 * process accounting. If the device is opened by root, we
1625 	 * instantly flag that we used superuser privs. Who knows,
1626 	 * we might close the device immediately without doing a
1627 	 * privileged operation -- cevans
1628 	 */
1629 	as->suser = capable(CAP_SYS_ADMIN);
1630 	as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
1631 	as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
1632 	spin_lock(&user_list_lock);
1633 	as->next = user_list;
1634 	user_list = as;
1635 	spin_unlock(&user_list_lock);
1636 	filp->private_data = as;
1637 	return 0;
1638 }
1639 
1640 static int proc_apm_show(struct seq_file *m, void *v)
1641 {
1642 	unsigned short	bx;
1643 	unsigned short	cx;
1644 	unsigned short	dx;
1645 	int		error;
1646 	unsigned short  ac_line_status = 0xff;
1647 	unsigned short  battery_status = 0xff;
1648 	unsigned short  battery_flag   = 0xff;
1649 	int		percentage     = -1;
1650 	int             time_units     = -1;
1651 	char            *units         = "?";
1652 
1653 	if ((num_online_cpus() == 1) &&
1654 	    !(error = apm_get_power_status(&bx, &cx, &dx))) {
1655 		ac_line_status = (bx >> 8) & 0xff;
1656 		battery_status = bx & 0xff;
1657 		if ((cx & 0xff) != 0xff)
1658 			percentage = cx & 0xff;
1659 
1660 		if (apm_info.connection_version > 0x100) {
1661 			battery_flag = (cx >> 8) & 0xff;
1662 			if (dx != 0xffff) {
1663 				units = (dx & 0x8000) ? "min" : "sec";
1664 				time_units = dx & 0x7fff;
1665 			}
1666 		}
1667 	}
1668 	/* Arguments, with symbols from linux/apm_bios.h.  Information is
1669 	   from the Get Power Status (0x0a) call unless otherwise noted.
1670 
1671 	   0) Linux driver version (this will change if format changes)
1672 	   1) APM BIOS Version.  Usually 1.0, 1.1 or 1.2.
1673 	   2) APM flags from APM Installation Check (0x00):
1674 	      bit 0: APM_16_BIT_SUPPORT
1675 	      bit 1: APM_32_BIT_SUPPORT
1676 	      bit 2: APM_IDLE_SLOWS_CLOCK
1677 	      bit 3: APM_BIOS_DISABLED
1678 	      bit 4: APM_BIOS_DISENGAGED
1679 	   3) AC line status
1680 	      0x00: Off-line
1681 	      0x01: On-line
1682 	      0x02: On backup power (BIOS >= 1.1 only)
1683 	      0xff: Unknown
1684 	   4) Battery status
1685 	      0x00: High
1686 	      0x01: Low
1687 	      0x02: Critical
1688 	      0x03: Charging
1689 	      0x04: Selected battery not present (BIOS >= 1.2 only)
1690 	      0xff: Unknown
1691 	   5) Battery flag
1692 	      bit 0: High
1693 	      bit 1: Low
1694 	      bit 2: Critical
1695 	      bit 3: Charging
1696 	      bit 7: No system battery
1697 	      0xff: Unknown
1698 	   6) Remaining battery life (percentage of charge):
1699 	      0-100: valid
1700 	      -1: Unknown
1701 	   7) Remaining battery life (time units):
1702 	      Number of remaining minutes or seconds
1703 	      -1: Unknown
1704 	   8) min = minutes; sec = seconds */
1705 
1706 	seq_printf(m, "%s %d.%d 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
1707 		   driver_version,
1708 		   (apm_info.bios.version >> 8) & 0xff,
1709 		   apm_info.bios.version & 0xff,
1710 		   apm_info.bios.flags,
1711 		   ac_line_status,
1712 		   battery_status,
1713 		   battery_flag,
1714 		   percentage,
1715 		   time_units,
1716 		   units);
1717 	return 0;
1718 }
1719 
1720 static int proc_apm_open(struct inode *inode, struct file *file)
1721 {
1722 	return single_open(file, proc_apm_show, NULL);
1723 }
1724 
1725 static const struct file_operations apm_file_ops = {
1726 	.owner		= THIS_MODULE,
1727 	.open		= proc_apm_open,
1728 	.read		= seq_read,
1729 	.llseek		= seq_lseek,
1730 	.release	= single_release,
1731 };
1732 
1733 static int apm(void *unused)
1734 {
1735 	unsigned short	bx;
1736 	unsigned short	cx;
1737 	unsigned short	dx;
1738 	int		error;
1739 	char 		*power_stat;
1740 	char 		*bat_stat;
1741 
1742 	/* 2002/08/01 - WT
1743 	 * This is to avoid random crashes at boot time during initialization
1744 	 * on SMP systems in case of "apm=power-off" mode. Seen on ASUS A7M266D.
1745 	 * Some bioses don't like being called from CPU != 0.
1746 	 * Method suggested by Ingo Molnar.
1747 	 */
1748 	set_cpus_allowed_ptr(current, cpumask_of(0));
1749 	BUG_ON(smp_processor_id() != 0);
1750 
1751 	if (apm_info.connection_version == 0) {
1752 		apm_info.connection_version = apm_info.bios.version;
1753 		if (apm_info.connection_version > 0x100) {
1754 			/*
1755 			 * We only support BIOSs up to version 1.2
1756 			 */
1757 			if (apm_info.connection_version > 0x0102)
1758 				apm_info.connection_version = 0x0102;
1759 			error = apm_driver_version(&apm_info.connection_version);
1760 			if (error != APM_SUCCESS) {
1761 				apm_error("driver version", error);
1762 				/* Fall back to an APM 1.0 connection. */
1763 				apm_info.connection_version = 0x100;
1764 			}
1765 		}
1766 	}
1767 
1768 	if (debug)
1769 		printk(KERN_INFO "apm: Connection version %d.%d\n",
1770 			(apm_info.connection_version >> 8) & 0xff,
1771 			apm_info.connection_version & 0xff);
1772 
1773 #ifdef CONFIG_APM_DO_ENABLE
1774 	if (apm_info.bios.flags & APM_BIOS_DISABLED) {
1775 		/*
1776 		 * This call causes my NEC UltraLite Versa 33/C to hang if it
1777 		 * is booted with PM disabled but not in the docking station.
1778 		 * Unfortunate ...
1779 		 */
1780 		error = apm_enable_power_management(1);
1781 		if (error) {
1782 			apm_error("enable power management", error);
1783 			return -1;
1784 		}
1785 	}
1786 #endif
1787 
1788 	if ((apm_info.bios.flags & APM_BIOS_DISENGAGED)
1789 	    && (apm_info.connection_version > 0x0100)) {
1790 		error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1791 		if (error) {
1792 			apm_error("engage power management", error);
1793 			return -1;
1794 		}
1795 	}
1796 
1797 	if (debug && (num_online_cpus() == 1 || smp)) {
1798 		error = apm_get_power_status(&bx, &cx, &dx);
1799 		if (error)
1800 			printk(KERN_INFO "apm: power status not available\n");
1801 		else {
1802 			switch ((bx >> 8) & 0xff) {
1803 			case 0:
1804 				power_stat = "off line";
1805 				break;
1806 			case 1:
1807 				power_stat = "on line";
1808 				break;
1809 			case 2:
1810 				power_stat = "on backup power";
1811 				break;
1812 			default:
1813 				power_stat = "unknown";
1814 				break;
1815 			}
1816 			switch (bx & 0xff) {
1817 			case 0:
1818 				bat_stat = "high";
1819 				break;
1820 			case 1:
1821 				bat_stat = "low";
1822 				break;
1823 			case 2:
1824 				bat_stat = "critical";
1825 				break;
1826 			case 3:
1827 				bat_stat = "charging";
1828 				break;
1829 			default:
1830 				bat_stat = "unknown";
1831 				break;
1832 			}
1833 			printk(KERN_INFO
1834 			       "apm: AC %s, battery status %s, battery life ",
1835 			       power_stat, bat_stat);
1836 			if ((cx & 0xff) == 0xff)
1837 				printk("unknown\n");
1838 			else
1839 				printk("%d%%\n", cx & 0xff);
1840 			if (apm_info.connection_version > 0x100) {
1841 				printk(KERN_INFO
1842 				       "apm: battery flag 0x%02x, battery life ",
1843 				       (cx >> 8) & 0xff);
1844 				if (dx == 0xffff)
1845 					printk("unknown\n");
1846 				else
1847 					printk("%d %s\n", dx & 0x7fff,
1848 					       (dx & 0x8000) ?
1849 					       "minutes" : "seconds");
1850 			}
1851 		}
1852 	}
1853 
1854 	/* Install our power off handler.. */
1855 	if (power_off)
1856 		pm_power_off = apm_power_off;
1857 
1858 	if (num_online_cpus() == 1 || smp) {
1859 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1860 		console_blank_hook = apm_console_blank;
1861 #endif
1862 		apm_mainloop();
1863 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1864 		console_blank_hook = NULL;
1865 #endif
1866 	}
1867 
1868 	return 0;
1869 }
1870 
1871 #ifndef MODULE
1872 static int __init apm_setup(char *str)
1873 {
1874 	int invert;
1875 
1876 	while ((str != NULL) && (*str != '\0')) {
1877 		if (strncmp(str, "off", 3) == 0)
1878 			apm_disabled = 1;
1879 		if (strncmp(str, "on", 2) == 0)
1880 			apm_disabled = 0;
1881 		if ((strncmp(str, "bounce-interval=", 16) == 0) ||
1882 		    (strncmp(str, "bounce_interval=", 16) == 0))
1883 			bounce_interval = simple_strtol(str + 16, NULL, 0);
1884 		if ((strncmp(str, "idle-threshold=", 15) == 0) ||
1885 		    (strncmp(str, "idle_threshold=", 15) == 0))
1886 			idle_threshold = simple_strtol(str + 15, NULL, 0);
1887 		if ((strncmp(str, "idle-period=", 12) == 0) ||
1888 		    (strncmp(str, "idle_period=", 12) == 0))
1889 			idle_period = simple_strtol(str + 12, NULL, 0);
1890 		invert = (strncmp(str, "no-", 3) == 0) ||
1891 			(strncmp(str, "no_", 3) == 0);
1892 		if (invert)
1893 			str += 3;
1894 		if (strncmp(str, "debug", 5) == 0)
1895 			debug = !invert;
1896 		if ((strncmp(str, "power-off", 9) == 0) ||
1897 		    (strncmp(str, "power_off", 9) == 0))
1898 			power_off = !invert;
1899 		if (strncmp(str, "smp", 3) == 0) {
1900 			smp = !invert;
1901 			idle_threshold = 100;
1902 		}
1903 		if ((strncmp(str, "allow-ints", 10) == 0) ||
1904 		    (strncmp(str, "allow_ints", 10) == 0))
1905 			apm_info.allow_ints = !invert;
1906 		if ((strncmp(str, "broken-psr", 10) == 0) ||
1907 		    (strncmp(str, "broken_psr", 10) == 0))
1908 			apm_info.get_power_status_broken = !invert;
1909 		if ((strncmp(str, "realmode-power-off", 18) == 0) ||
1910 		    (strncmp(str, "realmode_power_off", 18) == 0))
1911 			apm_info.realmode_power_off = !invert;
1912 		str = strchr(str, ',');
1913 		if (str != NULL)
1914 			str += strspn(str, ", \t");
1915 	}
1916 	return 1;
1917 }
1918 
1919 __setup("apm=", apm_setup);
1920 #endif
1921 
1922 static const struct file_operations apm_bios_fops = {
1923 	.owner		= THIS_MODULE,
1924 	.read		= do_read,
1925 	.poll		= do_poll,
1926 	.unlocked_ioctl	= do_ioctl,
1927 	.open		= do_open,
1928 	.release	= do_release,
1929 };
1930 
1931 static struct miscdevice apm_device = {
1932 	APM_MINOR_DEV,
1933 	"apm_bios",
1934 	&apm_bios_fops
1935 };
1936 
1937 
1938 /* Simple "print if true" callback */
1939 static int __init print_if_true(const struct dmi_system_id *d)
1940 {
1941 	printk("%s\n", d->ident);
1942 	return 0;
1943 }
1944 
1945 /*
1946  * Some Bioses enable the PS/2 mouse (touchpad) at resume, even if it was
1947  * disabled before the suspend. Linux used to get terribly confused by that.
1948  */
1949 static int __init broken_ps2_resume(const struct dmi_system_id *d)
1950 {
1951 	printk(KERN_INFO "%s machine detected. Mousepad Resume Bug "
1952 	       "workaround hopefully not needed.\n", d->ident);
1953 	return 0;
1954 }
1955 
1956 /* Some bioses have a broken protected mode poweroff and need to use realmode */
1957 static int __init set_realmode_power_off(const struct dmi_system_id *d)
1958 {
1959 	if (apm_info.realmode_power_off == 0) {
1960 		apm_info.realmode_power_off = 1;
1961 		printk(KERN_INFO "%s bios detected. "
1962 		       "Using realmode poweroff only.\n", d->ident);
1963 	}
1964 	return 0;
1965 }
1966 
1967 /* Some laptops require interrupts to be enabled during APM calls */
1968 static int __init set_apm_ints(const struct dmi_system_id *d)
1969 {
1970 	if (apm_info.allow_ints == 0) {
1971 		apm_info.allow_ints = 1;
1972 		printk(KERN_INFO "%s machine detected. "
1973 		       "Enabling interrupts during APM calls.\n", d->ident);
1974 	}
1975 	return 0;
1976 }
1977 
1978 /* Some APM bioses corrupt memory or just plain do not work */
1979 static int __init apm_is_horked(const struct dmi_system_id *d)
1980 {
1981 	if (apm_info.disabled == 0) {
1982 		apm_info.disabled = 1;
1983 		printk(KERN_INFO "%s machine detected. "
1984 		       "Disabling APM.\n", d->ident);
1985 	}
1986 	return 0;
1987 }
1988 
1989 static int __init apm_is_horked_d850md(const struct dmi_system_id *d)
1990 {
1991 	if (apm_info.disabled == 0) {
1992 		apm_info.disabled = 1;
1993 		printk(KERN_INFO "%s machine detected. "
1994 		       "Disabling APM.\n", d->ident);
1995 		printk(KERN_INFO "This bug is fixed in bios P15 which is available for \n");
1996 		printk(KERN_INFO "download from support.intel.com \n");
1997 	}
1998 	return 0;
1999 }
2000 
2001 /* Some APM bioses hang on APM idle calls */
2002 static int __init apm_likes_to_melt(const struct dmi_system_id *d)
2003 {
2004 	if (apm_info.forbid_idle == 0) {
2005 		apm_info.forbid_idle = 1;
2006 		printk(KERN_INFO "%s machine detected. "
2007 		       "Disabling APM idle calls.\n", d->ident);
2008 	}
2009 	return 0;
2010 }
2011 
2012 /*
2013  *  Check for clue free BIOS implementations who use
2014  *  the following QA technique
2015  *
2016  *      [ Write BIOS Code ]<------
2017  *               |                ^
2018  *      < Does it Compile >----N--
2019  *               |Y               ^
2020  *	< Does it Boot Win98 >-N--
2021  *               |Y
2022  *           [Ship It]
2023  *
2024  *	Phoenix A04  08/24/2000 is known bad (Dell Inspiron 5000e)
2025  *	Phoenix A07  09/29/2000 is known good (Dell Inspiron 5000)
2026  */
2027 static int __init broken_apm_power(const struct dmi_system_id *d)
2028 {
2029 	apm_info.get_power_status_broken = 1;
2030 	printk(KERN_WARNING "BIOS strings suggest APM bugs, "
2031 	       "disabling power status reporting.\n");
2032 	return 0;
2033 }
2034 
2035 /*
2036  * This bios swaps the APM minute reporting bytes over (Many sony laptops
2037  * have this problem).
2038  */
2039 static int __init swab_apm_power_in_minutes(const struct dmi_system_id *d)
2040 {
2041 	apm_info.get_power_status_swabinminutes = 1;
2042 	printk(KERN_WARNING "BIOS strings suggest APM reports battery life "
2043 	       "in minutes and wrong byte order.\n");
2044 	return 0;
2045 }
2046 
2047 static struct dmi_system_id __initdata apm_dmi_table[] = {
2048 	{
2049 		print_if_true,
2050 		KERN_WARNING "IBM T23 - BIOS 1.03b+ and controller firmware 1.02+ may be needed for Linux APM.",
2051 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
2052 			DMI_MATCH(DMI_BIOS_VERSION, "1AET38WW (1.01b)"), },
2053 	},
2054 	{	/* Handle problems with APM on the C600 */
2055 		broken_ps2_resume, "Dell Latitude C600",
2056 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
2057 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C600"), },
2058 	},
2059 	{	/* Allow interrupts during suspend on Dell Latitude laptops*/
2060 		set_apm_ints, "Dell Latitude",
2061 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2062 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C510"), }
2063 	},
2064 	{	/* APM crashes */
2065 		apm_is_horked, "Dell Inspiron 2500",
2066 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2067 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2068 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2069 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2070 	},
2071 	{	/* Allow interrupts during suspend on Dell Inspiron laptops*/
2072 		set_apm_ints, "Dell Inspiron", {
2073 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2074 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 4000"), },
2075 	},
2076 	{	/* Handle problems with APM on Inspiron 5000e */
2077 		broken_apm_power, "Dell Inspiron 5000e",
2078 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2079 			DMI_MATCH(DMI_BIOS_VERSION, "A04"),
2080 			DMI_MATCH(DMI_BIOS_DATE, "08/24/2000"), },
2081 	},
2082 	{	/* Handle problems with APM on Inspiron 2500 */
2083 		broken_apm_power, "Dell Inspiron 2500",
2084 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2085 			DMI_MATCH(DMI_BIOS_VERSION, "A12"),
2086 			DMI_MATCH(DMI_BIOS_DATE, "02/04/2002"), },
2087 	},
2088 	{	/* APM crashes */
2089 		apm_is_horked, "Dell Dimension 4100",
2090 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2091 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"),
2092 			DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2093 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2094 	},
2095 	{	/* Allow interrupts during suspend on Compaq Laptops*/
2096 		set_apm_ints, "Compaq 12XL125",
2097 		{	DMI_MATCH(DMI_SYS_VENDOR, "Compaq"),
2098 			DMI_MATCH(DMI_PRODUCT_NAME, "Compaq PC"),
2099 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2100 			DMI_MATCH(DMI_BIOS_VERSION, "4.06"), },
2101 	},
2102 	{	/* Allow interrupts during APM or the clock goes slow */
2103 		set_apm_ints, "ASUSTeK",
2104 		{	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
2105 			DMI_MATCH(DMI_PRODUCT_NAME, "L8400K series Notebook PC"), },
2106 	},
2107 	{	/* APM blows on shutdown */
2108 		apm_is_horked, "ABIT KX7-333[R]",
2109 		{	DMI_MATCH(DMI_BOARD_VENDOR, "ABIT"),
2110 			DMI_MATCH(DMI_BOARD_NAME, "VT8367-8233A (KX7-333[R])"), },
2111 	},
2112 	{	/* APM crashes */
2113 		apm_is_horked, "Trigem Delhi3",
2114 		{	DMI_MATCH(DMI_SYS_VENDOR, "TriGem Computer, Inc"),
2115 			DMI_MATCH(DMI_PRODUCT_NAME, "Delhi3"), },
2116 	},
2117 	{	/* APM crashes */
2118 		apm_is_horked, "Fujitsu-Siemens",
2119 		{	DMI_MATCH(DMI_BIOS_VENDOR, "hoenix/FUJITSU SIEMENS"),
2120 			DMI_MATCH(DMI_BIOS_VERSION, "Version1.01"), },
2121 	},
2122 	{	/* APM crashes */
2123 		apm_is_horked_d850md, "Intel D850MD",
2124 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2125 			DMI_MATCH(DMI_BIOS_VERSION, "MV85010A.86A.0016.P07.0201251536"), },
2126 	},
2127 	{	/* APM crashes */
2128 		apm_is_horked, "Intel D810EMO",
2129 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2130 			DMI_MATCH(DMI_BIOS_VERSION, "MO81010A.86A.0008.P04.0004170800"), },
2131 	},
2132 	{	/* APM crashes */
2133 		apm_is_horked, "Dell XPS-Z",
2134 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2135 			DMI_MATCH(DMI_BIOS_VERSION, "A11"),
2136 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"), },
2137 	},
2138 	{	/* APM crashes */
2139 		apm_is_horked, "Sharp PC-PJ/AX",
2140 		{	DMI_MATCH(DMI_SYS_VENDOR, "SHARP"),
2141 			DMI_MATCH(DMI_PRODUCT_NAME, "PC-PJ/AX"),
2142 			DMI_MATCH(DMI_BIOS_VENDOR, "SystemSoft"),
2143 			DMI_MATCH(DMI_BIOS_VERSION, "Version R2.08"), },
2144 	},
2145 	{	/* APM crashes */
2146 		apm_is_horked, "Dell Inspiron 2500",
2147 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2148 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2149 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2150 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2151 	},
2152 	{	/* APM idle hangs */
2153 		apm_likes_to_melt, "Jabil AMD",
2154 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2155 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP06"), },
2156 	},
2157 	{	/* APM idle hangs */
2158 		apm_likes_to_melt, "AMI Bios",
2159 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2160 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP05"), },
2161 	},
2162 	{	/* Handle problems with APM on Sony Vaio PCG-N505X(DE) */
2163 		swab_apm_power_in_minutes, "Sony VAIO",
2164 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2165 			DMI_MATCH(DMI_BIOS_VERSION, "R0206H"),
2166 			DMI_MATCH(DMI_BIOS_DATE, "08/23/99"), },
2167 	},
2168 	{	/* Handle problems with APM on Sony Vaio PCG-N505VX */
2169 		swab_apm_power_in_minutes, "Sony VAIO",
2170 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2171 			DMI_MATCH(DMI_BIOS_VERSION, "W2K06H0"),
2172 			DMI_MATCH(DMI_BIOS_DATE, "02/03/00"), },
2173 	},
2174 	{	/* Handle problems with APM on Sony Vaio PCG-XG29 */
2175 		swab_apm_power_in_minutes, "Sony VAIO",
2176 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2177 			DMI_MATCH(DMI_BIOS_VERSION, "R0117A0"),
2178 			DMI_MATCH(DMI_BIOS_DATE, "04/25/00"), },
2179 	},
2180 	{	/* Handle problems with APM on Sony Vaio PCG-Z600NE */
2181 		swab_apm_power_in_minutes, "Sony VAIO",
2182 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2183 			DMI_MATCH(DMI_BIOS_VERSION, "R0121Z1"),
2184 			DMI_MATCH(DMI_BIOS_DATE, "05/11/00"), },
2185 	},
2186 	{	/* Handle problems with APM on Sony Vaio PCG-Z600NE */
2187 		swab_apm_power_in_minutes, "Sony VAIO",
2188 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2189 			DMI_MATCH(DMI_BIOS_VERSION, "WME01Z1"),
2190 			DMI_MATCH(DMI_BIOS_DATE, "08/11/00"), },
2191 	},
2192 	{	/* Handle problems with APM on Sony Vaio PCG-Z600LEK(DE) */
2193 		swab_apm_power_in_minutes, "Sony VAIO",
2194 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2195 			DMI_MATCH(DMI_BIOS_VERSION, "R0206Z3"),
2196 			DMI_MATCH(DMI_BIOS_DATE, "12/25/00"), },
2197 	},
2198 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS */
2199 		swab_apm_power_in_minutes, "Sony VAIO",
2200 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2201 			DMI_MATCH(DMI_BIOS_VERSION, "R0203D0"),
2202 			DMI_MATCH(DMI_BIOS_DATE, "05/12/00"), },
2203 	},
2204 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS */
2205 		swab_apm_power_in_minutes, "Sony VAIO",
2206 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2207 			DMI_MATCH(DMI_BIOS_VERSION, "R0203Z3"),
2208 			DMI_MATCH(DMI_BIOS_DATE, "08/25/00"), },
2209 	},
2210 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS (with updated BIOS) */
2211 		swab_apm_power_in_minutes, "Sony VAIO",
2212 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2213 			DMI_MATCH(DMI_BIOS_VERSION, "R0209Z3"),
2214 			DMI_MATCH(DMI_BIOS_DATE, "05/12/01"), },
2215 	},
2216 	{	/* Handle problems with APM on Sony Vaio PCG-F104K */
2217 		swab_apm_power_in_minutes, "Sony VAIO",
2218 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2219 			DMI_MATCH(DMI_BIOS_VERSION, "R0204K2"),
2220 			DMI_MATCH(DMI_BIOS_DATE, "08/28/00"), },
2221 	},
2222 
2223 	{	/* Handle problems with APM on Sony Vaio PCG-C1VN/C1VE */
2224 		swab_apm_power_in_minutes, "Sony VAIO",
2225 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2226 			DMI_MATCH(DMI_BIOS_VERSION, "R0208P1"),
2227 			DMI_MATCH(DMI_BIOS_DATE, "11/09/00"), },
2228 	},
2229 	{	/* Handle problems with APM on Sony Vaio PCG-C1VE */
2230 		swab_apm_power_in_minutes, "Sony VAIO",
2231 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2232 			DMI_MATCH(DMI_BIOS_VERSION, "R0204P1"),
2233 			DMI_MATCH(DMI_BIOS_DATE, "09/12/00"), },
2234 	},
2235 	{	/* Handle problems with APM on Sony Vaio PCG-C1VE */
2236 		swab_apm_power_in_minutes, "Sony VAIO",
2237 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2238 			DMI_MATCH(DMI_BIOS_VERSION, "WXPO1Z3"),
2239 			DMI_MATCH(DMI_BIOS_DATE, "10/26/01"), },
2240 	},
2241 	{	/* broken PM poweroff bios */
2242 		set_realmode_power_off, "Award Software v4.60 PGMA",
2243 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Award Software International, Inc."),
2244 			DMI_MATCH(DMI_BIOS_VERSION, "4.60 PGMA"),
2245 			DMI_MATCH(DMI_BIOS_DATE, "134526184"), },
2246 	},
2247 
2248 	/* Generic per vendor APM settings  */
2249 
2250 	{	/* Allow interrupts during suspend on IBM laptops */
2251 		set_apm_ints, "IBM",
2252 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"), },
2253 	},
2254 
2255 	{ }
2256 };
2257 
2258 /*
2259  * Just start the APM thread. We do NOT want to do APM BIOS
2260  * calls from anything but the APM thread, if for no other reason
2261  * than the fact that we don't trust the APM BIOS. This way,
2262  * most common APM BIOS problems that lead to protection errors
2263  * etc will have at least some level of being contained...
2264  *
2265  * In short, if something bad happens, at least we have a choice
2266  * of just killing the apm thread..
2267  */
2268 static int __init apm_init(void)
2269 {
2270 	struct desc_struct *gdt;
2271 	int err;
2272 
2273 	dmi_check_system(apm_dmi_table);
2274 
2275 	if (apm_info.bios.version == 0 || paravirt_enabled() || machine_is_olpc()) {
2276 		printk(KERN_INFO "apm: BIOS not found.\n");
2277 		return -ENODEV;
2278 	}
2279 	printk(KERN_INFO
2280 	       "apm: BIOS version %d.%d Flags 0x%02x (Driver version %s)\n",
2281 	       ((apm_info.bios.version >> 8) & 0xff),
2282 	       (apm_info.bios.version & 0xff),
2283 	       apm_info.bios.flags,
2284 	       driver_version);
2285 	if ((apm_info.bios.flags & APM_32_BIT_SUPPORT) == 0) {
2286 		printk(KERN_INFO "apm: no 32 bit BIOS support\n");
2287 		return -ENODEV;
2288 	}
2289 
2290 	if (allow_ints)
2291 		apm_info.allow_ints = 1;
2292 	if (broken_psr)
2293 		apm_info.get_power_status_broken = 1;
2294 	if (realmode_power_off)
2295 		apm_info.realmode_power_off = 1;
2296 	/* User can override, but default is to trust DMI */
2297 	if (apm_disabled != -1)
2298 		apm_info.disabled = apm_disabled;
2299 
2300 	/*
2301 	 * Fix for the Compaq Contura 3/25c which reports BIOS version 0.1
2302 	 * but is reportedly a 1.0 BIOS.
2303 	 */
2304 	if (apm_info.bios.version == 0x001)
2305 		apm_info.bios.version = 0x100;
2306 
2307 	/* BIOS < 1.2 doesn't set cseg_16_len */
2308 	if (apm_info.bios.version < 0x102)
2309 		apm_info.bios.cseg_16_len = 0; /* 64k */
2310 
2311 	if (debug) {
2312 		printk(KERN_INFO "apm: entry %x:%x cseg16 %x dseg %x",
2313 			apm_info.bios.cseg, apm_info.bios.offset,
2314 			apm_info.bios.cseg_16, apm_info.bios.dseg);
2315 		if (apm_info.bios.version > 0x100)
2316 			printk(" cseg len %x, dseg len %x",
2317 				apm_info.bios.cseg_len,
2318 				apm_info.bios.dseg_len);
2319 		if (apm_info.bios.version > 0x101)
2320 			printk(" cseg16 len %x", apm_info.bios.cseg_16_len);
2321 		printk("\n");
2322 	}
2323 
2324 	if (apm_info.disabled) {
2325 		printk(KERN_NOTICE "apm: disabled on user request.\n");
2326 		return -ENODEV;
2327 	}
2328 	if ((num_online_cpus() > 1) && !power_off && !smp) {
2329 		printk(KERN_NOTICE "apm: disabled - APM is not SMP safe.\n");
2330 		apm_info.disabled = 1;
2331 		return -ENODEV;
2332 	}
2333 	if (pm_flags & PM_ACPI) {
2334 		printk(KERN_NOTICE "apm: overridden by ACPI.\n");
2335 		apm_info.disabled = 1;
2336 		return -ENODEV;
2337 	}
2338 	pm_flags |= PM_APM;
2339 
2340 	/*
2341 	 * Set up the long jump entry point to the APM BIOS, which is called
2342 	 * from inline assembly.
2343 	 */
2344 	apm_bios_entry.offset = apm_info.bios.offset;
2345 	apm_bios_entry.segment = APM_CS;
2346 
2347 	/*
2348 	 * The APM 1.1 BIOS is supposed to provide limit information that it
2349 	 * recognizes.  Many machines do this correctly, but many others do
2350 	 * not restrict themselves to their claimed limit.  When this happens,
2351 	 * they will cause a segmentation violation in the kernel at boot time.
2352 	 * Most BIOS's, however, will respect a 64k limit, so we use that.
2353 	 *
2354 	 * Note we only set APM segments on CPU zero, since we pin the APM
2355 	 * code to that CPU.
2356 	 */
2357 	gdt = get_cpu_gdt_table(0);
2358 	set_desc_base(&gdt[APM_CS >> 3],
2359 		 (unsigned long)__va((unsigned long)apm_info.bios.cseg << 4));
2360 	set_desc_base(&gdt[APM_CS_16 >> 3],
2361 		 (unsigned long)__va((unsigned long)apm_info.bios.cseg_16 << 4));
2362 	set_desc_base(&gdt[APM_DS >> 3],
2363 		 (unsigned long)__va((unsigned long)apm_info.bios.dseg << 4));
2364 
2365 	proc_create("apm", 0, NULL, &apm_file_ops);
2366 
2367 	kapmd_task = kthread_create(apm, NULL, "kapmd");
2368 	if (IS_ERR(kapmd_task)) {
2369 		printk(KERN_ERR "apm: disabled - Unable to start kernel "
2370 				"thread.\n");
2371 		err = PTR_ERR(kapmd_task);
2372 		kapmd_task = NULL;
2373 		remove_proc_entry("apm", NULL);
2374 		return err;
2375 	}
2376 	wake_up_process(kapmd_task);
2377 
2378 	if (num_online_cpus() > 1 && !smp) {
2379 		printk(KERN_NOTICE
2380 		       "apm: disabled - APM is not SMP safe (power off active).\n");
2381 		return 0;
2382 	}
2383 
2384 	/*
2385 	 * Note we don't actually care if the misc_device cannot be registered.
2386 	 * this driver can do its job without it, even if userspace can't
2387 	 * control it.  just log the error
2388 	 */
2389 	if (misc_register(&apm_device))
2390 		printk(KERN_WARNING "apm: Could not register misc device.\n");
2391 
2392 	if (HZ != 100)
2393 		idle_period = (idle_period * HZ) / 100;
2394 	if (idle_threshold < 100) {
2395 		original_pm_idle = pm_idle;
2396 		pm_idle  = apm_cpu_idle;
2397 		set_pm_idle = 1;
2398 	}
2399 
2400 	return 0;
2401 }
2402 
2403 static void __exit apm_exit(void)
2404 {
2405 	int error;
2406 
2407 	if (set_pm_idle) {
2408 		pm_idle = original_pm_idle;
2409 		/*
2410 		 * We are about to unload the current idle thread pm callback
2411 		 * (pm_idle), Wait for all processors to update cached/local
2412 		 * copies of pm_idle before proceeding.
2413 		 */
2414 		cpu_idle_wait();
2415 	}
2416 	if (((apm_info.bios.flags & APM_BIOS_DISENGAGED) == 0)
2417 	    && (apm_info.connection_version > 0x0100)) {
2418 		error = apm_engage_power_management(APM_DEVICE_ALL, 0);
2419 		if (error)
2420 			apm_error("disengage power management", error);
2421 	}
2422 	misc_deregister(&apm_device);
2423 	remove_proc_entry("apm", NULL);
2424 	if (power_off)
2425 		pm_power_off = NULL;
2426 	if (kapmd_task) {
2427 		kthread_stop(kapmd_task);
2428 		kapmd_task = NULL;
2429 	}
2430 	pm_flags &= ~PM_APM;
2431 }
2432 
2433 module_init(apm_init);
2434 module_exit(apm_exit);
2435 
2436 MODULE_AUTHOR("Stephen Rothwell");
2437 MODULE_DESCRIPTION("Advanced Power Management");
2438 MODULE_LICENSE("GPL");
2439 module_param(debug, bool, 0644);
2440 MODULE_PARM_DESC(debug, "Enable debug mode");
2441 module_param(power_off, bool, 0444);
2442 MODULE_PARM_DESC(power_off, "Enable power off");
2443 module_param(bounce_interval, int, 0444);
2444 MODULE_PARM_DESC(bounce_interval,
2445 		"Set the number of ticks to ignore suspend bounces");
2446 module_param(allow_ints, bool, 0444);
2447 MODULE_PARM_DESC(allow_ints, "Allow interrupts during BIOS calls");
2448 module_param(broken_psr, bool, 0444);
2449 MODULE_PARM_DESC(broken_psr, "BIOS has a broken GetPowerStatus call");
2450 module_param(realmode_power_off, bool, 0444);
2451 MODULE_PARM_DESC(realmode_power_off,
2452 		"Switch to real mode before powering off");
2453 module_param(idle_threshold, int, 0444);
2454 MODULE_PARM_DESC(idle_threshold,
2455 	"System idle percentage above which to make APM BIOS idle calls");
2456 module_param(idle_period, int, 0444);
2457 MODULE_PARM_DESC(idle_period,
2458 	"Period (in sec/100) over which to caculate the idle percentage");
2459 module_param(smp, bool, 0444);
2460 MODULE_PARM_DESC(smp,
2461 	"Set this to enable APM use on an SMP platform. Use with caution on older systems");
2462 MODULE_ALIAS_MISCDEV(APM_MINOR_DEV);
2463