xref: /openbmc/linux/arch/x86/kernel/apm_32.c (revision d0b73b48)
1 /* -*- linux-c -*-
2  * APM BIOS driver for Linux
3  * Copyright 1994-2001 Stephen Rothwell (sfr@canb.auug.org.au)
4  *
5  * Initial development of this driver was funded by NEC Australia P/L
6  *	and NEC Corporation
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms of the GNU General Public License as published by the
10  * Free Software Foundation; either version 2, or (at your option) any
11  * later version.
12  *
13  * This program is distributed in the hope that it will be useful, but
14  * WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * General Public License for more details.
17  *
18  * October 1995, Rik Faith (faith@cs.unc.edu):
19  *    Minor enhancements and updates (to the patch set) for 1.3.x
20  *    Documentation
21  * January 1996, Rik Faith (faith@cs.unc.edu):
22  *    Make /proc/apm easy to format (bump driver version)
23  * March 1996, Rik Faith (faith@cs.unc.edu):
24  *    Prohibit APM BIOS calls unless apm_enabled.
25  *    (Thanks to Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>)
26  * April 1996, Stephen Rothwell (sfr@canb.auug.org.au)
27  *    Version 1.0 and 1.1
28  * May 1996, Version 1.2
29  * Feb 1998, Version 1.3
30  * Feb 1998, Version 1.4
31  * Aug 1998, Version 1.5
32  * Sep 1998, Version 1.6
33  * Nov 1998, Version 1.7
34  * Jan 1999, Version 1.8
35  * Jan 1999, Version 1.9
36  * Oct 1999, Version 1.10
37  * Nov 1999, Version 1.11
38  * Jan 2000, Version 1.12
39  * Feb 2000, Version 1.13
40  * Nov 2000, Version 1.14
41  * Oct 2001, Version 1.15
42  * Jan 2002, Version 1.16
43  * Oct 2002, Version 1.16ac
44  *
45  * History:
46  *    0.6b: first version in official kernel, Linux 1.3.46
47  *    0.7: changed /proc/apm format, Linux 1.3.58
48  *    0.8: fixed gcc 2.7.[12] compilation problems, Linux 1.3.59
49  *    0.9: only call bios if bios is present, Linux 1.3.72
50  *    1.0: use fixed device number, consolidate /proc/apm into this file,
51  *         Linux 1.3.85
52  *    1.1: support user-space standby and suspend, power off after system
53  *         halted, Linux 1.3.98
54  *    1.2: When resetting RTC after resume, take care so that the time
55  *         is only incorrect by 30-60mS (vs. 1S previously) (Gabor J. Toth
56  *         <jtoth@princeton.edu>); improve interaction between
57  *         screen-blanking and gpm (Stephen Rothwell); Linux 1.99.4
58  *    1.2a:Simple change to stop mysterious bug reports with SMP also added
59  *	   levels to the printk calls. APM is not defined for SMP machines.
60  *         The new replacement for it is, but Linux doesn't yet support this.
61  *         Alan Cox Linux 2.1.55
62  *    1.3: Set up a valid data descriptor 0x40 for buggy BIOS's
63  *    1.4: Upgraded to support APM 1.2. Integrated ThinkPad suspend patch by
64  *         Dean Gaudet <dgaudet@arctic.org>.
65  *         C. Scott Ananian <cananian@alumni.princeton.edu> Linux 2.1.87
66  *    1.5: Fix segment register reloading (in case of bad segments saved
67  *         across BIOS call).
68  *         Stephen Rothwell
69  *    1.6: Cope with compiler/assembler differences.
70  *         Only try to turn off the first display device.
71  *         Fix OOPS at power off with no APM BIOS by Jan Echternach
72  *                   <echter@informatik.uni-rostock.de>
73  *         Stephen Rothwell
74  *    1.7: Modify driver's cached copy of the disabled/disengaged flags
75  *         to reflect current state of APM BIOS.
76  *         Chris Rankin <rankinc@bellsouth.net>
77  *         Reset interrupt 0 timer to 100Hz after suspend
78  *         Chad Miller <cmiller@surfsouth.com>
79  *         Add CONFIG_APM_IGNORE_SUSPEND_BOUNCE
80  *         Richard Gooch <rgooch@atnf.csiro.au>
81  *         Allow boot time disabling of APM
82  *         Make boot messages far less verbose by default
83  *         Make asm safer
84  *         Stephen Rothwell
85  *    1.8: Add CONFIG_APM_RTC_IS_GMT
86  *         Richard Gooch <rgooch@atnf.csiro.au>
87  *         change APM_NOINTS to CONFIG_APM_ALLOW_INTS
88  *         remove dependency on CONFIG_PROC_FS
89  *         Stephen Rothwell
90  *    1.9: Fix small typo.  <laslo@wodip.opole.pl>
91  *         Try to cope with BIOS's that need to have all display
92  *         devices blanked and not just the first one.
93  *         Ross Paterson <ross@soi.city.ac.uk>
94  *         Fix segment limit setting it has always been wrong as
95  *         the segments needed to have byte granularity.
96  *         Mark a few things __init.
97  *         Add hack to allow power off of SMP systems by popular request.
98  *         Use CONFIG_SMP instead of __SMP__
99  *         Ignore BOUNCES for three seconds.
100  *         Stephen Rothwell
101  *   1.10: Fix for Thinkpad return code.
102  *         Merge 2.2 and 2.3 drivers.
103  *         Remove APM dependencies in arch/i386/kernel/process.c
104  *         Remove APM dependencies in drivers/char/sysrq.c
105  *         Reset time across standby.
106  *         Allow more inititialisation on SMP.
107  *         Remove CONFIG_APM_POWER_OFF and make it boot time
108  *         configurable (default on).
109  *         Make debug only a boot time parameter (remove APM_DEBUG).
110  *         Try to blank all devices on any error.
111  *   1.11: Remove APM dependencies in drivers/char/console.c
112  *         Check nr_running to detect if we are idle (from
113  *         Borislav Deianov <borislav@lix.polytechnique.fr>)
114  *         Fix for bioses that don't zero the top part of the
115  *         entrypoint offset (Mario Sitta <sitta@al.unipmn.it>)
116  *         (reported by Panos Katsaloulis <teras@writeme.com>).
117  *         Real mode power off patch (Walter Hofmann
118  *         <Walter.Hofmann@physik.stud.uni-erlangen.de>).
119  *   1.12: Remove CONFIG_SMP as the compiler will optimize
120  *         the code away anyway (smp_num_cpus == 1 in UP)
121  *         noted by Artur Skawina <skawina@geocities.com>.
122  *         Make power off under SMP work again.
123  *         Fix thinko with initial engaging of BIOS.
124  *         Make sure power off only happens on CPU 0
125  *         (Paul "Rusty" Russell <rusty@rustcorp.com.au>).
126  *         Do error notification to user mode if BIOS calls fail.
127  *         Move entrypoint offset fix to ...boot/setup.S
128  *         where it belongs (Cosmos <gis88564@cis.nctu.edu.tw>).
129  *         Remove smp-power-off. SMP users must now specify
130  *         "apm=power-off" on the kernel command line. Suggested
131  *         by Jim Avera <jima@hal.com>, modified by Alan Cox
132  *         <alan@lxorguk.ukuu.org.uk>.
133  *         Register the /proc/apm entry even on SMP so that
134  *         scripts that check for it before doing power off
135  *         work (Jim Avera <jima@hal.com>).
136  *   1.13: Changes for new pm_ interfaces (Andy Henroid
137  *         <andy_henroid@yahoo.com>).
138  *         Modularize the code.
139  *         Fix the Thinkpad (again) :-( (CONFIG_APM_IGNORE_MULTIPLE_SUSPENDS
140  *         is now the way life works).
141  *         Fix thinko in suspend() (wrong return).
142  *         Notify drivers on critical suspend.
143  *         Make kapmd absorb more idle time (Pavel Machek <pavel@ucw.cz>
144  *         modified by sfr).
145  *         Disable interrupts while we are suspended (Andy Henroid
146  *         <andy_henroid@yahoo.com> fixed by sfr).
147  *         Make power off work on SMP again (Tony Hoyle
148  *         <tmh@magenta-logic.com> and <zlatko@iskon.hr>) modified by sfr.
149  *         Remove CONFIG_APM_SUSPEND_BOUNCE.  The bounce ignore
150  *         interval is now configurable.
151  *   1.14: Make connection version persist across module unload/load.
152  *         Enable and engage power management earlier.
153  *         Disengage power management on module unload.
154  *         Changed to use the sysrq-register hack for registering the
155  *         power off function called by magic sysrq based upon discussions
156  *         in irc://irc.openprojects.net/#kernelnewbies
157  *         (Crutcher Dunnavant <crutcher+kernel@datastacks.com>).
158  *         Make CONFIG_APM_REAL_MODE_POWER_OFF run time configurable.
159  *         (Arjan van de Ven <arjanv@redhat.com>) modified by sfr.
160  *         Work around byte swap bug in one of the Vaio's BIOS's
161  *         (Marc Boucher <marc@mbsi.ca>).
162  *         Exposed the disable flag to dmi so that we can handle known
163  *         broken APM (Alan Cox <alan@lxorguk.ukuu.org.uk>).
164  *   1.14ac: If the BIOS says "I slowed the CPU down" then don't spin
165  *         calling it - instead idle. (Alan Cox <alan@lxorguk.ukuu.org.uk>)
166  *         If an APM idle fails log it and idle sensibly
167  *   1.15: Don't queue events to clients who open the device O_WRONLY.
168  *         Don't expect replies from clients who open the device O_RDONLY.
169  *         (Idea from Thomas Hood)
170  *         Minor waitqueue cleanups. (John Fremlin <chief@bandits.org>)
171  *   1.16: Fix idle calling. (Andreas Steinmetz <ast@domdv.de> et al.)
172  *         Notify listeners of standby or suspend events before notifying
173  *         drivers. Return EBUSY to ioctl() if suspend is rejected.
174  *         (Russell King <rmk@arm.linux.org.uk> and Thomas Hood)
175  *         Ignore first resume after we generate our own resume event
176  *         after a suspend (Thomas Hood)
177  *         Daemonize now gets rid of our controlling terminal (sfr).
178  *         CONFIG_APM_CPU_IDLE now just affects the default value of
179  *         idle_threshold (sfr).
180  *         Change name of kernel apm daemon (as it no longer idles) (sfr).
181  *   1.16ac: Fix up SMP support somewhat. You can now force SMP on and we
182  *	   make _all_ APM calls on the CPU#0. Fix unsafe sign bug.
183  *	   TODO: determine if its "boot CPU" or "CPU0" we want to lock to.
184  *
185  * APM 1.1 Reference:
186  *
187  *   Intel Corporation, Microsoft Corporation. Advanced Power Management
188  *   (APM) BIOS Interface Specification, Revision 1.1, September 1993.
189  *   Intel Order Number 241704-001.  Microsoft Part Number 781-110-X01.
190  *
191  * [This document is available free from Intel by calling 800.628.8686 (fax
192  * 916.356.6100) or 800.548.4725; or from
193  * http://www.microsoft.com/whdc/archive/amp_12.mspx  It is also
194  * available from Microsoft by calling 206.882.8080.]
195  *
196  * APM 1.2 Reference:
197  *   Intel Corporation, Microsoft Corporation. Advanced Power Management
198  *   (APM) BIOS Interface Specification, Revision 1.2, February 1996.
199  *
200  * [This document is available from Microsoft at:
201  *    http://www.microsoft.com/whdc/archive/amp_12.mspx]
202  */
203 
204 #define pr_fmt(fmt) "apm: " fmt
205 
206 #include <linux/module.h>
207 
208 #include <linux/poll.h>
209 #include <linux/types.h>
210 #include <linux/stddef.h>
211 #include <linux/timer.h>
212 #include <linux/fcntl.h>
213 #include <linux/slab.h>
214 #include <linux/stat.h>
215 #include <linux/proc_fs.h>
216 #include <linux/seq_file.h>
217 #include <linux/miscdevice.h>
218 #include <linux/apm_bios.h>
219 #include <linux/init.h>
220 #include <linux/time.h>
221 #include <linux/sched.h>
222 #include <linux/pm.h>
223 #include <linux/capability.h>
224 #include <linux/device.h>
225 #include <linux/kernel.h>
226 #include <linux/freezer.h>
227 #include <linux/smp.h>
228 #include <linux/dmi.h>
229 #include <linux/suspend.h>
230 #include <linux/kthread.h>
231 #include <linux/jiffies.h>
232 #include <linux/acpi.h>
233 #include <linux/syscore_ops.h>
234 #include <linux/i8253.h>
235 
236 #include <asm/uaccess.h>
237 #include <asm/desc.h>
238 #include <asm/olpc.h>
239 #include <asm/paravirt.h>
240 #include <asm/reboot.h>
241 
242 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
243 extern int (*console_blank_hook)(int);
244 #endif
245 
246 /*
247  * The apm_bios device is one of the misc char devices.
248  * This is its minor number.
249  */
250 #define	APM_MINOR_DEV	134
251 
252 /*
253  * Various options can be changed at boot time as follows:
254  * (We allow underscores for compatibility with the modules code)
255  *	apm=on/off			enable/disable APM
256  *	    [no-]allow[-_]ints		allow interrupts during BIOS calls
257  *	    [no-]broken[-_]psr		BIOS has a broken GetPowerStatus call
258  *	    [no-]realmode[-_]power[-_]off	switch to real mode before
259  *	    					powering off
260  *	    [no-]debug			log some debugging messages
261  *	    [no-]power[-_]off		power off on shutdown
262  *	    [no-]smp			Use apm even on an SMP box
263  *	    bounce[-_]interval=<n>	number of ticks to ignore suspend
264  *	    				bounces
265  *          idle[-_]threshold=<n>       System idle percentage above which to
266  *                                      make APM BIOS idle calls. Set it to
267  *                                      100 to disable.
268  *          idle[-_]period=<n>          Period (in 1/100s of a second) over
269  *                                      which the idle percentage is
270  *                                      calculated.
271  */
272 
273 /* KNOWN PROBLEM MACHINES:
274  *
275  * U: TI 4000M TravelMate: BIOS is *NOT* APM compliant
276  *                         [Confirmed by TI representative]
277  * ?: ACER 486DX4/75: uses dseg 0040, in violation of APM specification
278  *                    [Confirmed by BIOS disassembly]
279  *                    [This may work now ...]
280  * P: Toshiba 1950S: battery life information only gets updated after resume
281  * P: Midwest Micro Soundbook Elite DX2/66 monochrome: screen blanking
282  * 	broken in BIOS [Reported by Garst R. Reese <reese@isn.net>]
283  * ?: AcerNote-950: oops on reading /proc/apm - workaround is a WIP
284  * 	Neale Banks <neale@lowendale.com.au> December 2000
285  *
286  * Legend: U = unusable with APM patches
287  *         P = partially usable with APM patches
288  */
289 
290 /*
291  * Define as 1 to make the driver always call the APM BIOS busy
292  * routine even if the clock was not reported as slowed by the
293  * idle routine.  Otherwise, define as 0.
294  */
295 #define ALWAYS_CALL_BUSY   1
296 
297 /*
298  * Define to make the APM BIOS calls zero all data segment registers (so
299  * that an incorrect BIOS implementation will cause a kernel panic if it
300  * tries to write to arbitrary memory).
301  */
302 #define APM_ZERO_SEGS
303 
304 #include <asm/apm.h>
305 
306 /*
307  * Define to re-initialize the interrupt 0 timer to 100 Hz after a suspend.
308  * This patched by Chad Miller <cmiller@surfsouth.com>, original code by
309  * David Chen <chen@ctpa04.mit.edu>
310  */
311 #undef INIT_TIMER_AFTER_SUSPEND
312 
313 #ifdef INIT_TIMER_AFTER_SUSPEND
314 #include <linux/timex.h>
315 #include <asm/io.h>
316 #include <linux/delay.h>
317 #endif
318 
319 /*
320  * Need to poll the APM BIOS every second
321  */
322 #define APM_CHECK_TIMEOUT	(HZ)
323 
324 /*
325  * Ignore suspend events for this amount of time after a resume
326  */
327 #define DEFAULT_BOUNCE_INTERVAL	(3 * HZ)
328 
329 /*
330  * Maximum number of events stored
331  */
332 #define APM_MAX_EVENTS		20
333 
334 /*
335  * The per-file APM data
336  */
337 struct apm_user {
338 	int		magic;
339 	struct apm_user *next;
340 	unsigned int	suser: 1;
341 	unsigned int	writer: 1;
342 	unsigned int	reader: 1;
343 	unsigned int	suspend_wait: 1;
344 	int		suspend_result;
345 	int		suspends_pending;
346 	int		standbys_pending;
347 	int		suspends_read;
348 	int		standbys_read;
349 	int		event_head;
350 	int		event_tail;
351 	apm_event_t	events[APM_MAX_EVENTS];
352 };
353 
354 /*
355  * The magic number in apm_user
356  */
357 #define APM_BIOS_MAGIC		0x4101
358 
359 /*
360  * idle percentage above which bios idle calls are done
361  */
362 #ifdef CONFIG_APM_CPU_IDLE
363 #warning deprecated CONFIG_APM_CPU_IDLE will be deleted in 2012
364 #define DEFAULT_IDLE_THRESHOLD	95
365 #else
366 #define DEFAULT_IDLE_THRESHOLD	100
367 #endif
368 #define DEFAULT_IDLE_PERIOD	(100 / 3)
369 
370 /*
371  * Local variables
372  */
373 static struct {
374 	unsigned long	offset;
375 	unsigned short	segment;
376 } apm_bios_entry;
377 static int clock_slowed;
378 static int idle_threshold __read_mostly = DEFAULT_IDLE_THRESHOLD;
379 static int idle_period __read_mostly = DEFAULT_IDLE_PERIOD;
380 static int set_pm_idle;
381 static int suspends_pending;
382 static int standbys_pending;
383 static int ignore_sys_suspend;
384 static int ignore_normal_resume;
385 static int bounce_interval __read_mostly = DEFAULT_BOUNCE_INTERVAL;
386 
387 static bool debug __read_mostly;
388 static bool smp __read_mostly;
389 static int apm_disabled = -1;
390 #ifdef CONFIG_SMP
391 static bool power_off;
392 #else
393 static bool power_off = 1;
394 #endif
395 static bool realmode_power_off;
396 #ifdef CONFIG_APM_ALLOW_INTS
397 static bool allow_ints = 1;
398 #else
399 static bool allow_ints;
400 #endif
401 static bool broken_psr;
402 
403 static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
404 static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
405 static struct apm_user *user_list;
406 static DEFINE_SPINLOCK(user_list_lock);
407 static DEFINE_MUTEX(apm_mutex);
408 
409 /*
410  * Set up a segment that references the real mode segment 0x40
411  * that extends up to the end of page zero (that we have reserved).
412  * This is for buggy BIOS's that refer to (real mode) segment 0x40
413  * even though they are called in protected mode.
414  */
415 static struct desc_struct bad_bios_desc = GDT_ENTRY_INIT(0x4092,
416 			(unsigned long)__va(0x400UL), PAGE_SIZE - 0x400 - 1);
417 
418 static const char driver_version[] = "1.16ac";	/* no spaces */
419 
420 static struct task_struct *kapmd_task;
421 
422 /*
423  *	APM event names taken from the APM 1.2 specification. These are
424  *	the message codes that the BIOS uses to tell us about events
425  */
426 static const char * const apm_event_name[] = {
427 	"system standby",
428 	"system suspend",
429 	"normal resume",
430 	"critical resume",
431 	"low battery",
432 	"power status change",
433 	"update time",
434 	"critical suspend",
435 	"user standby",
436 	"user suspend",
437 	"system standby resume",
438 	"capabilities change"
439 };
440 #define NR_APM_EVENT_NAME ARRAY_SIZE(apm_event_name)
441 
442 typedef struct lookup_t {
443 	int	key;
444 	char 	*msg;
445 } lookup_t;
446 
447 /*
448  *	The BIOS returns a set of standard error codes in AX when the
449  *	carry flag is set.
450  */
451 
452 static const lookup_t error_table[] = {
453 /* N/A	{ APM_SUCCESS,		"Operation succeeded" }, */
454 	{ APM_DISABLED,		"Power management disabled" },
455 	{ APM_CONNECTED,	"Real mode interface already connected" },
456 	{ APM_NOT_CONNECTED,	"Interface not connected" },
457 	{ APM_16_CONNECTED,	"16 bit interface already connected" },
458 /* N/A	{ APM_16_UNSUPPORTED,	"16 bit interface not supported" }, */
459 	{ APM_32_CONNECTED,	"32 bit interface already connected" },
460 	{ APM_32_UNSUPPORTED,	"32 bit interface not supported" },
461 	{ APM_BAD_DEVICE,	"Unrecognized device ID" },
462 	{ APM_BAD_PARAM,	"Parameter out of range" },
463 	{ APM_NOT_ENGAGED,	"Interface not engaged" },
464 	{ APM_BAD_FUNCTION,     "Function not supported" },
465 	{ APM_RESUME_DISABLED,	"Resume timer disabled" },
466 	{ APM_BAD_STATE,	"Unable to enter requested state" },
467 /* N/A	{ APM_NO_EVENTS,	"No events pending" }, */
468 	{ APM_NO_ERROR,		"BIOS did not set a return code" },
469 	{ APM_NOT_PRESENT,	"No APM present" }
470 };
471 #define ERROR_COUNT	ARRAY_SIZE(error_table)
472 
473 /**
474  *	apm_error	-	display an APM error
475  *	@str: information string
476  *	@err: APM BIOS return code
477  *
478  *	Write a meaningful log entry to the kernel log in the event of
479  *	an APM error.  Note that this also handles (negative) kernel errors.
480  */
481 
482 static void apm_error(char *str, int err)
483 {
484 	int i;
485 
486 	for (i = 0; i < ERROR_COUNT; i++)
487 		if (error_table[i].key == err)
488 			break;
489 	if (i < ERROR_COUNT)
490 		pr_notice("%s: %s\n", str, error_table[i].msg);
491 	else if (err < 0)
492 		pr_notice("%s: linux error code %i\n", str, err);
493 	else
494 		pr_notice("%s: unknown error code %#2.2x\n",
495 		       str, err);
496 }
497 
498 /*
499  * These are the actual BIOS calls.  Depending on APM_ZERO_SEGS and
500  * apm_info.allow_ints, we are being really paranoid here!  Not only
501  * are interrupts disabled, but all the segment registers (except SS)
502  * are saved and zeroed this means that if the BIOS tries to reference
503  * any data without explicitly loading the segment registers, the kernel
504  * will fault immediately rather than have some unforeseen circumstances
505  * for the rest of the kernel.  And it will be very obvious!  :-) Doing
506  * this depends on CS referring to the same physical memory as DS so that
507  * DS can be zeroed before the call. Unfortunately, we can't do anything
508  * about the stack segment/pointer.  Also, we tell the compiler that
509  * everything could change.
510  *
511  * Also, we KNOW that for the non error case of apm_bios_call, there
512  * is no useful data returned in the low order 8 bits of eax.
513  */
514 
515 static inline unsigned long __apm_irq_save(void)
516 {
517 	unsigned long flags;
518 	local_save_flags(flags);
519 	if (apm_info.allow_ints) {
520 		if (irqs_disabled_flags(flags))
521 			local_irq_enable();
522 	} else
523 		local_irq_disable();
524 
525 	return flags;
526 }
527 
528 #define apm_irq_save(flags) \
529 	do { flags = __apm_irq_save(); } while (0)
530 
531 static inline void apm_irq_restore(unsigned long flags)
532 {
533 	if (irqs_disabled_flags(flags))
534 		local_irq_disable();
535 	else if (irqs_disabled())
536 		local_irq_enable();
537 }
538 
539 #ifdef APM_ZERO_SEGS
540 #	define APM_DECL_SEGS \
541 		unsigned int saved_fs; unsigned int saved_gs;
542 #	define APM_DO_SAVE_SEGS \
543 		savesegment(fs, saved_fs); savesegment(gs, saved_gs)
544 #	define APM_DO_RESTORE_SEGS \
545 		loadsegment(fs, saved_fs); loadsegment(gs, saved_gs)
546 #else
547 #	define APM_DECL_SEGS
548 #	define APM_DO_SAVE_SEGS
549 #	define APM_DO_RESTORE_SEGS
550 #endif
551 
552 struct apm_bios_call {
553 	u32 func;
554 	/* In and out */
555 	u32 ebx;
556 	u32 ecx;
557 	/* Out only */
558 	u32 eax;
559 	u32 edx;
560 	u32 esi;
561 
562 	/* Error: -ENOMEM, or bits 8-15 of eax */
563 	int err;
564 };
565 
566 /**
567  *	__apm_bios_call - Make an APM BIOS 32bit call
568  *	@_call: pointer to struct apm_bios_call.
569  *
570  *	Make an APM call using the 32bit protected mode interface. The
571  *	caller is responsible for knowing if APM BIOS is configured and
572  *	enabled. This call can disable interrupts for a long period of
573  *	time on some laptops.  The return value is in AH and the carry
574  *	flag is loaded into AL.  If there is an error, then the error
575  *	code is returned in AH (bits 8-15 of eax) and this function
576  *	returns non-zero.
577  *
578  *	Note: this makes the call on the current CPU.
579  */
580 static long __apm_bios_call(void *_call)
581 {
582 	APM_DECL_SEGS
583 	unsigned long		flags;
584 	int			cpu;
585 	struct desc_struct	save_desc_40;
586 	struct desc_struct	*gdt;
587 	struct apm_bios_call	*call = _call;
588 
589 	cpu = get_cpu();
590 	BUG_ON(cpu != 0);
591 	gdt = get_cpu_gdt_table(cpu);
592 	save_desc_40 = gdt[0x40 / 8];
593 	gdt[0x40 / 8] = bad_bios_desc;
594 
595 	apm_irq_save(flags);
596 	APM_DO_SAVE_SEGS;
597 	apm_bios_call_asm(call->func, call->ebx, call->ecx,
598 			  &call->eax, &call->ebx, &call->ecx, &call->edx,
599 			  &call->esi);
600 	APM_DO_RESTORE_SEGS;
601 	apm_irq_restore(flags);
602 	gdt[0x40 / 8] = save_desc_40;
603 	put_cpu();
604 
605 	return call->eax & 0xff;
606 }
607 
608 /* Run __apm_bios_call or __apm_bios_call_simple on CPU 0 */
609 static int on_cpu0(long (*fn)(void *), struct apm_bios_call *call)
610 {
611 	int ret;
612 
613 	/* Don't bother with work_on_cpu in the common case, so we don't
614 	 * have to worry about OOM or overhead. */
615 	if (get_cpu() == 0) {
616 		ret = fn(call);
617 		put_cpu();
618 	} else {
619 		put_cpu();
620 		ret = work_on_cpu(0, fn, call);
621 	}
622 
623 	/* work_on_cpu can fail with -ENOMEM */
624 	if (ret < 0)
625 		call->err = ret;
626 	else
627 		call->err = (call->eax >> 8) & 0xff;
628 
629 	return ret;
630 }
631 
632 /**
633  *	apm_bios_call	-	Make an APM BIOS 32bit call (on CPU 0)
634  *	@call: the apm_bios_call registers.
635  *
636  *	If there is an error, it is returned in @call.err.
637  */
638 static int apm_bios_call(struct apm_bios_call *call)
639 {
640 	return on_cpu0(__apm_bios_call, call);
641 }
642 
643 /**
644  *	__apm_bios_call_simple - Make an APM BIOS 32bit call (on CPU 0)
645  *	@_call: pointer to struct apm_bios_call.
646  *
647  *	Make a BIOS call that returns one value only, or just status.
648  *	If there is an error, then the error code is returned in AH
649  *	(bits 8-15 of eax) and this function returns non-zero (it can
650  *	also return -ENOMEM). This is used for simpler BIOS operations.
651  *	This call may hold interrupts off for a long time on some laptops.
652  *
653  *	Note: this makes the call on the current CPU.
654  */
655 static long __apm_bios_call_simple(void *_call)
656 {
657 	u8			error;
658 	APM_DECL_SEGS
659 	unsigned long		flags;
660 	int			cpu;
661 	struct desc_struct	save_desc_40;
662 	struct desc_struct	*gdt;
663 	struct apm_bios_call	*call = _call;
664 
665 	cpu = get_cpu();
666 	BUG_ON(cpu != 0);
667 	gdt = get_cpu_gdt_table(cpu);
668 	save_desc_40 = gdt[0x40 / 8];
669 	gdt[0x40 / 8] = bad_bios_desc;
670 
671 	apm_irq_save(flags);
672 	APM_DO_SAVE_SEGS;
673 	error = apm_bios_call_simple_asm(call->func, call->ebx, call->ecx,
674 					 &call->eax);
675 	APM_DO_RESTORE_SEGS;
676 	apm_irq_restore(flags);
677 	gdt[0x40 / 8] = save_desc_40;
678 	put_cpu();
679 	return error;
680 }
681 
682 /**
683  *	apm_bios_call_simple	-	make a simple APM BIOS 32bit call
684  *	@func: APM function to invoke
685  *	@ebx_in: EBX register value for BIOS call
686  *	@ecx_in: ECX register value for BIOS call
687  *	@eax: EAX register on return from the BIOS call
688  *	@err: bits
689  *
690  *	Make a BIOS call that returns one value only, or just status.
691  *	If there is an error, then the error code is returned in @err
692  *	and this function returns non-zero. This is used for simpler
693  *	BIOS operations.  This call may hold interrupts off for a long
694  *	time on some laptops.
695  */
696 static int apm_bios_call_simple(u32 func, u32 ebx_in, u32 ecx_in, u32 *eax,
697 				int *err)
698 {
699 	struct apm_bios_call call;
700 	int ret;
701 
702 	call.func = func;
703 	call.ebx = ebx_in;
704 	call.ecx = ecx_in;
705 
706 	ret = on_cpu0(__apm_bios_call_simple, &call);
707 	*eax = call.eax;
708 	*err = call.err;
709 	return ret;
710 }
711 
712 /**
713  *	apm_driver_version	-	APM driver version
714  *	@val:	loaded with the APM version on return
715  *
716  *	Retrieve the APM version supported by the BIOS. This is only
717  *	supported for APM 1.1 or higher. An error indicates APM 1.0 is
718  *	probably present.
719  *
720  *	On entry val should point to a value indicating the APM driver
721  *	version with the high byte being the major and the low byte the
722  *	minor number both in BCD
723  *
724  *	On return it will hold the BIOS revision supported in the
725  *	same format.
726  */
727 
728 static int apm_driver_version(u_short *val)
729 {
730 	u32 eax;
731 	int err;
732 
733 	if (apm_bios_call_simple(APM_FUNC_VERSION, 0, *val, &eax, &err))
734 		return err;
735 	*val = eax;
736 	return APM_SUCCESS;
737 }
738 
739 /**
740  *	apm_get_event	-	get an APM event from the BIOS
741  *	@event: pointer to the event
742  *	@info: point to the event information
743  *
744  *	The APM BIOS provides a polled information for event
745  *	reporting. The BIOS expects to be polled at least every second
746  *	when events are pending. When a message is found the caller should
747  *	poll until no more messages are present.  However, this causes
748  *	problems on some laptops where a suspend event notification is
749  *	not cleared until it is acknowledged.
750  *
751  *	Additional information is returned in the info pointer, providing
752  *	that APM 1.2 is in use. If no messges are pending the value 0x80
753  *	is returned (No power management events pending).
754  */
755 static int apm_get_event(apm_event_t *event, apm_eventinfo_t *info)
756 {
757 	struct apm_bios_call call;
758 
759 	call.func = APM_FUNC_GET_EVENT;
760 	call.ebx = call.ecx = 0;
761 
762 	if (apm_bios_call(&call))
763 		return call.err;
764 
765 	*event = call.ebx;
766 	if (apm_info.connection_version < 0x0102)
767 		*info = ~0; /* indicate info not valid */
768 	else
769 		*info = call.ecx;
770 	return APM_SUCCESS;
771 }
772 
773 /**
774  *	set_power_state	-	set the power management state
775  *	@what: which items to transition
776  *	@state: state to transition to
777  *
778  *	Request an APM change of state for one or more system devices. The
779  *	processor state must be transitioned last of all. what holds the
780  *	class of device in the upper byte and the device number (0xFF for
781  *	all) for the object to be transitioned.
782  *
783  *	The state holds the state to transition to, which may in fact
784  *	be an acceptance of a BIOS requested state change.
785  */
786 
787 static int set_power_state(u_short what, u_short state)
788 {
789 	u32 eax;
790 	int err;
791 
792 	if (apm_bios_call_simple(APM_FUNC_SET_STATE, what, state, &eax, &err))
793 		return err;
794 	return APM_SUCCESS;
795 }
796 
797 /**
798  *	set_system_power_state - set system wide power state
799  *	@state: which state to enter
800  *
801  *	Transition the entire system into a new APM power state.
802  */
803 
804 static int set_system_power_state(u_short state)
805 {
806 	return set_power_state(APM_DEVICE_ALL, state);
807 }
808 
809 /**
810  *	apm_do_idle	-	perform power saving
811  *
812  *	This function notifies the BIOS that the processor is (in the view
813  *	of the OS) idle. It returns -1 in the event that the BIOS refuses
814  *	to handle the idle request. On a success the function returns 1
815  *	if the BIOS did clock slowing or 0 otherwise.
816  */
817 
818 static int apm_do_idle(void)
819 {
820 	u32 eax;
821 	u8 ret = 0;
822 	int idled = 0;
823 	int polling;
824 	int err = 0;
825 
826 	polling = !!(current_thread_info()->status & TS_POLLING);
827 	if (polling) {
828 		current_thread_info()->status &= ~TS_POLLING;
829 		/*
830 		 * TS_POLLING-cleared state must be visible before we
831 		 * test NEED_RESCHED:
832 		 */
833 		smp_mb();
834 	}
835 	if (!need_resched()) {
836 		idled = 1;
837 		ret = apm_bios_call_simple(APM_FUNC_IDLE, 0, 0, &eax, &err);
838 	}
839 	if (polling)
840 		current_thread_info()->status |= TS_POLLING;
841 
842 	if (!idled)
843 		return 0;
844 
845 	if (ret) {
846 		static unsigned long t;
847 
848 		/* This always fails on some SMP boards running UP kernels.
849 		 * Only report the failure the first 5 times.
850 		 */
851 		if (++t < 5) {
852 			printk(KERN_DEBUG "apm_do_idle failed (%d)\n", err);
853 			t = jiffies;
854 		}
855 		return -1;
856 	}
857 	clock_slowed = (apm_info.bios.flags & APM_IDLE_SLOWS_CLOCK) != 0;
858 	return clock_slowed;
859 }
860 
861 /**
862  *	apm_do_busy	-	inform the BIOS the CPU is busy
863  *
864  *	Request that the BIOS brings the CPU back to full performance.
865  */
866 
867 static void apm_do_busy(void)
868 {
869 	u32 dummy;
870 	int err;
871 
872 	if (clock_slowed || ALWAYS_CALL_BUSY) {
873 		(void)apm_bios_call_simple(APM_FUNC_BUSY, 0, 0, &dummy, &err);
874 		clock_slowed = 0;
875 	}
876 }
877 
878 /*
879  * If no process has really been interested in
880  * the CPU for some time, we want to call BIOS
881  * power management - we probably want
882  * to conserve power.
883  */
884 #define IDLE_CALC_LIMIT	(HZ * 100)
885 #define IDLE_LEAKY_MAX	16
886 
887 static void (*original_pm_idle)(void) __read_mostly;
888 
889 /**
890  * apm_cpu_idle		-	cpu idling for APM capable Linux
891  *
892  * This is the idling function the kernel executes when APM is available. It
893  * tries to do BIOS powermanagement based on the average system idle time.
894  * Furthermore it calls the system default idle routine.
895  */
896 
897 static void apm_cpu_idle(void)
898 {
899 	static int use_apm_idle; /* = 0 */
900 	static unsigned int last_jiffies; /* = 0 */
901 	static unsigned int last_stime; /* = 0 */
902 
903 	int apm_idle_done = 0;
904 	unsigned int jiffies_since_last_check = jiffies - last_jiffies;
905 	unsigned int bucket;
906 
907 	WARN_ONCE(1, "deprecated apm_cpu_idle will be deleted in 2012");
908 recalc:
909 	if (jiffies_since_last_check > IDLE_CALC_LIMIT) {
910 		use_apm_idle = 0;
911 		last_jiffies = jiffies;
912 		last_stime = current->stime;
913 	} else if (jiffies_since_last_check > idle_period) {
914 		unsigned int idle_percentage;
915 
916 		idle_percentage = current->stime - last_stime;
917 		idle_percentage *= 100;
918 		idle_percentage /= jiffies_since_last_check;
919 		use_apm_idle = (idle_percentage > idle_threshold);
920 		if (apm_info.forbid_idle)
921 			use_apm_idle = 0;
922 		last_jiffies = jiffies;
923 		last_stime = current->stime;
924 	}
925 
926 	bucket = IDLE_LEAKY_MAX;
927 
928 	while (!need_resched()) {
929 		if (use_apm_idle) {
930 			unsigned int t;
931 
932 			t = jiffies;
933 			switch (apm_do_idle()) {
934 			case 0:
935 				apm_idle_done = 1;
936 				if (t != jiffies) {
937 					if (bucket) {
938 						bucket = IDLE_LEAKY_MAX;
939 						continue;
940 					}
941 				} else if (bucket) {
942 					bucket--;
943 					continue;
944 				}
945 				break;
946 			case 1:
947 				apm_idle_done = 1;
948 				break;
949 			default: /* BIOS refused */
950 				break;
951 			}
952 		}
953 		if (original_pm_idle)
954 			original_pm_idle();
955 		else
956 			default_idle();
957 		local_irq_disable();
958 		jiffies_since_last_check = jiffies - last_jiffies;
959 		if (jiffies_since_last_check > idle_period)
960 			goto recalc;
961 	}
962 
963 	if (apm_idle_done)
964 		apm_do_busy();
965 
966 	local_irq_enable();
967 }
968 
969 /**
970  *	apm_power_off	-	ask the BIOS to power off
971  *
972  *	Handle the power off sequence. This is the one piece of code we
973  *	will execute even on SMP machines. In order to deal with BIOS
974  *	bugs we support real mode APM BIOS power off calls. We also make
975  *	the SMP call on CPU0 as some systems will only honour this call
976  *	on their first cpu.
977  */
978 
979 static void apm_power_off(void)
980 {
981 	/* Some bioses don't like being called from CPU != 0 */
982 	if (apm_info.realmode_power_off) {
983 		set_cpus_allowed_ptr(current, cpumask_of(0));
984 		machine_real_restart(MRR_APM);
985 	} else {
986 		(void)set_system_power_state(APM_STATE_OFF);
987 	}
988 }
989 
990 #ifdef CONFIG_APM_DO_ENABLE
991 
992 /**
993  *	apm_enable_power_management - enable BIOS APM power management
994  *	@enable: enable yes/no
995  *
996  *	Enable or disable the APM BIOS power services.
997  */
998 
999 static int apm_enable_power_management(int enable)
1000 {
1001 	u32 eax;
1002 	int err;
1003 
1004 	if ((enable == 0) && (apm_info.bios.flags & APM_BIOS_DISENGAGED))
1005 		return APM_NOT_ENGAGED;
1006 	if (apm_bios_call_simple(APM_FUNC_ENABLE_PM, APM_DEVICE_BALL,
1007 				 enable, &eax, &err))
1008 		return err;
1009 	if (enable)
1010 		apm_info.bios.flags &= ~APM_BIOS_DISABLED;
1011 	else
1012 		apm_info.bios.flags |= APM_BIOS_DISABLED;
1013 	return APM_SUCCESS;
1014 }
1015 #endif
1016 
1017 /**
1018  *	apm_get_power_status	-	get current power state
1019  *	@status: returned status
1020  *	@bat: battery info
1021  *	@life: estimated life
1022  *
1023  *	Obtain the current power status from the APM BIOS. We return a
1024  *	status which gives the rough battery status, and current power
1025  *	source. The bat value returned give an estimate as a percentage
1026  *	of life and a status value for the battery. The estimated life
1027  *	if reported is a lifetime in secodnds/minutes at current powwer
1028  *	consumption.
1029  */
1030 
1031 static int apm_get_power_status(u_short *status, u_short *bat, u_short *life)
1032 {
1033 	struct apm_bios_call call;
1034 
1035 	call.func = APM_FUNC_GET_STATUS;
1036 	call.ebx = APM_DEVICE_ALL;
1037 	call.ecx = 0;
1038 
1039 	if (apm_info.get_power_status_broken)
1040 		return APM_32_UNSUPPORTED;
1041 	if (apm_bios_call(&call))
1042 		return call.err;
1043 	*status = call.ebx;
1044 	*bat = call.ecx;
1045 	if (apm_info.get_power_status_swabinminutes) {
1046 		*life = swab16((u16)call.edx);
1047 		*life |= 0x8000;
1048 	} else
1049 		*life = call.edx;
1050 	return APM_SUCCESS;
1051 }
1052 
1053 #if 0
1054 static int apm_get_battery_status(u_short which, u_short *status,
1055 				  u_short *bat, u_short *life, u_short *nbat)
1056 {
1057 	u32 eax;
1058 	u32 ebx;
1059 	u32 ecx;
1060 	u32 edx;
1061 	u32 esi;
1062 
1063 	if (apm_info.connection_version < 0x0102) {
1064 		/* pretend we only have one battery. */
1065 		if (which != 1)
1066 			return APM_BAD_DEVICE;
1067 		*nbat = 1;
1068 		return apm_get_power_status(status, bat, life);
1069 	}
1070 
1071 	if (apm_bios_call(APM_FUNC_GET_STATUS, (0x8000 | (which)), 0, &eax,
1072 			  &ebx, &ecx, &edx, &esi))
1073 		return (eax >> 8) & 0xff;
1074 	*status = ebx;
1075 	*bat = ecx;
1076 	*life = edx;
1077 	*nbat = esi;
1078 	return APM_SUCCESS;
1079 }
1080 #endif
1081 
1082 /**
1083  *	apm_engage_power_management	-	enable PM on a device
1084  *	@device: identity of device
1085  *	@enable: on/off
1086  *
1087  *	Activate or deactive power management on either a specific device
1088  *	or the entire system (%APM_DEVICE_ALL).
1089  */
1090 
1091 static int apm_engage_power_management(u_short device, int enable)
1092 {
1093 	u32 eax;
1094 	int err;
1095 
1096 	if ((enable == 0) && (device == APM_DEVICE_ALL)
1097 	    && (apm_info.bios.flags & APM_BIOS_DISABLED))
1098 		return APM_DISABLED;
1099 	if (apm_bios_call_simple(APM_FUNC_ENGAGE_PM, device, enable,
1100 				 &eax, &err))
1101 		return err;
1102 	if (device == APM_DEVICE_ALL) {
1103 		if (enable)
1104 			apm_info.bios.flags &= ~APM_BIOS_DISENGAGED;
1105 		else
1106 			apm_info.bios.flags |= APM_BIOS_DISENGAGED;
1107 	}
1108 	return APM_SUCCESS;
1109 }
1110 
1111 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1112 
1113 /**
1114  *	apm_console_blank	-	blank the display
1115  *	@blank: on/off
1116  *
1117  *	Attempt to blank the console, firstly by blanking just video device
1118  *	zero, and if that fails (some BIOSes don't support it) then it blanks
1119  *	all video devices. Typically the BIOS will do laptop backlight and
1120  *	monitor powerdown for us.
1121  */
1122 
1123 static int apm_console_blank(int blank)
1124 {
1125 	int error = APM_NOT_ENGAGED; /* silence gcc */
1126 	int i;
1127 	u_short state;
1128 	static const u_short dev[3] = { 0x100, 0x1FF, 0x101 };
1129 
1130 	state = blank ? APM_STATE_STANDBY : APM_STATE_READY;
1131 
1132 	for (i = 0; i < ARRAY_SIZE(dev); i++) {
1133 		error = set_power_state(dev[i], state);
1134 
1135 		if ((error == APM_SUCCESS) || (error == APM_NO_ERROR))
1136 			return 1;
1137 
1138 		if (error == APM_NOT_ENGAGED)
1139 			break;
1140 	}
1141 
1142 	if (error == APM_NOT_ENGAGED) {
1143 		static int tried;
1144 		int eng_error;
1145 		if (tried++ == 0) {
1146 			eng_error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1147 			if (eng_error) {
1148 				apm_error("set display", error);
1149 				apm_error("engage interface", eng_error);
1150 				return 0;
1151 			} else
1152 				return apm_console_blank(blank);
1153 		}
1154 	}
1155 	apm_error("set display", error);
1156 	return 0;
1157 }
1158 #endif
1159 
1160 static int queue_empty(struct apm_user *as)
1161 {
1162 	return as->event_head == as->event_tail;
1163 }
1164 
1165 static apm_event_t get_queued_event(struct apm_user *as)
1166 {
1167 	if (++as->event_tail >= APM_MAX_EVENTS)
1168 		as->event_tail = 0;
1169 	return as->events[as->event_tail];
1170 }
1171 
1172 static void queue_event(apm_event_t event, struct apm_user *sender)
1173 {
1174 	struct apm_user *as;
1175 
1176 	spin_lock(&user_list_lock);
1177 	if (user_list == NULL)
1178 		goto out;
1179 	for (as = user_list; as != NULL; as = as->next) {
1180 		if ((as == sender) || (!as->reader))
1181 			continue;
1182 		if (++as->event_head >= APM_MAX_EVENTS)
1183 			as->event_head = 0;
1184 
1185 		if (as->event_head == as->event_tail) {
1186 			static int notified;
1187 
1188 			if (notified++ == 0)
1189 				pr_err("an event queue overflowed\n");
1190 			if (++as->event_tail >= APM_MAX_EVENTS)
1191 				as->event_tail = 0;
1192 		}
1193 		as->events[as->event_head] = event;
1194 		if (!as->suser || !as->writer)
1195 			continue;
1196 		switch (event) {
1197 		case APM_SYS_SUSPEND:
1198 		case APM_USER_SUSPEND:
1199 			as->suspends_pending++;
1200 			suspends_pending++;
1201 			break;
1202 
1203 		case APM_SYS_STANDBY:
1204 		case APM_USER_STANDBY:
1205 			as->standbys_pending++;
1206 			standbys_pending++;
1207 			break;
1208 		}
1209 	}
1210 	wake_up_interruptible(&apm_waitqueue);
1211 out:
1212 	spin_unlock(&user_list_lock);
1213 }
1214 
1215 static void reinit_timer(void)
1216 {
1217 #ifdef INIT_TIMER_AFTER_SUSPEND
1218 	unsigned long flags;
1219 
1220 	raw_spin_lock_irqsave(&i8253_lock, flags);
1221 	/* set the clock to HZ */
1222 	outb_p(0x34, PIT_MODE);		/* binary, mode 2, LSB/MSB, ch 0 */
1223 	udelay(10);
1224 	outb_p(LATCH & 0xff, PIT_CH0);	/* LSB */
1225 	udelay(10);
1226 	outb_p(LATCH >> 8, PIT_CH0);	/* MSB */
1227 	udelay(10);
1228 	raw_spin_unlock_irqrestore(&i8253_lock, flags);
1229 #endif
1230 }
1231 
1232 static int suspend(int vetoable)
1233 {
1234 	int err;
1235 	struct apm_user	*as;
1236 
1237 	dpm_suspend_start(PMSG_SUSPEND);
1238 	dpm_suspend_end(PMSG_SUSPEND);
1239 
1240 	local_irq_disable();
1241 	syscore_suspend();
1242 
1243 	local_irq_enable();
1244 
1245 	save_processor_state();
1246 	err = set_system_power_state(APM_STATE_SUSPEND);
1247 	ignore_normal_resume = 1;
1248 	restore_processor_state();
1249 
1250 	local_irq_disable();
1251 	reinit_timer();
1252 
1253 	if (err == APM_NO_ERROR)
1254 		err = APM_SUCCESS;
1255 	if (err != APM_SUCCESS)
1256 		apm_error("suspend", err);
1257 	err = (err == APM_SUCCESS) ? 0 : -EIO;
1258 
1259 	syscore_resume();
1260 	local_irq_enable();
1261 
1262 	dpm_resume_start(PMSG_RESUME);
1263 	dpm_resume_end(PMSG_RESUME);
1264 
1265 	queue_event(APM_NORMAL_RESUME, NULL);
1266 	spin_lock(&user_list_lock);
1267 	for (as = user_list; as != NULL; as = as->next) {
1268 		as->suspend_wait = 0;
1269 		as->suspend_result = err;
1270 	}
1271 	spin_unlock(&user_list_lock);
1272 	wake_up_interruptible(&apm_suspend_waitqueue);
1273 	return err;
1274 }
1275 
1276 static void standby(void)
1277 {
1278 	int err;
1279 
1280 	dpm_suspend_end(PMSG_SUSPEND);
1281 
1282 	local_irq_disable();
1283 	syscore_suspend();
1284 	local_irq_enable();
1285 
1286 	err = set_system_power_state(APM_STATE_STANDBY);
1287 	if ((err != APM_SUCCESS) && (err != APM_NO_ERROR))
1288 		apm_error("standby", err);
1289 
1290 	local_irq_disable();
1291 	syscore_resume();
1292 	local_irq_enable();
1293 
1294 	dpm_resume_start(PMSG_RESUME);
1295 }
1296 
1297 static apm_event_t get_event(void)
1298 {
1299 	int error;
1300 	apm_event_t event = APM_NO_EVENTS; /* silence gcc */
1301 	apm_eventinfo_t	info;
1302 
1303 	static int notified;
1304 
1305 	/* we don't use the eventinfo */
1306 	error = apm_get_event(&event, &info);
1307 	if (error == APM_SUCCESS)
1308 		return event;
1309 
1310 	if ((error != APM_NO_EVENTS) && (notified++ == 0))
1311 		apm_error("get_event", error);
1312 
1313 	return 0;
1314 }
1315 
1316 static void check_events(void)
1317 {
1318 	apm_event_t event;
1319 	static unsigned long last_resume;
1320 	static int ignore_bounce;
1321 
1322 	while ((event = get_event()) != 0) {
1323 		if (debug) {
1324 			if (event <= NR_APM_EVENT_NAME)
1325 				printk(KERN_DEBUG "apm: received %s notify\n",
1326 				       apm_event_name[event - 1]);
1327 			else
1328 				printk(KERN_DEBUG "apm: received unknown "
1329 				       "event 0x%02x\n", event);
1330 		}
1331 		if (ignore_bounce
1332 		    && (time_after(jiffies, last_resume + bounce_interval)))
1333 			ignore_bounce = 0;
1334 
1335 		switch (event) {
1336 		case APM_SYS_STANDBY:
1337 		case APM_USER_STANDBY:
1338 			queue_event(event, NULL);
1339 			if (standbys_pending <= 0)
1340 				standby();
1341 			break;
1342 
1343 		case APM_USER_SUSPEND:
1344 #ifdef CONFIG_APM_IGNORE_USER_SUSPEND
1345 			if (apm_info.connection_version > 0x100)
1346 				set_system_power_state(APM_STATE_REJECT);
1347 			break;
1348 #endif
1349 		case APM_SYS_SUSPEND:
1350 			if (ignore_bounce) {
1351 				if (apm_info.connection_version > 0x100)
1352 					set_system_power_state(APM_STATE_REJECT);
1353 				break;
1354 			}
1355 			/*
1356 			 * If we are already processing a SUSPEND,
1357 			 * then further SUSPEND events from the BIOS
1358 			 * will be ignored.  We also return here to
1359 			 * cope with the fact that the Thinkpads keep
1360 			 * sending a SUSPEND event until something else
1361 			 * happens!
1362 			 */
1363 			if (ignore_sys_suspend)
1364 				return;
1365 			ignore_sys_suspend = 1;
1366 			queue_event(event, NULL);
1367 			if (suspends_pending <= 0)
1368 				(void) suspend(1);
1369 			break;
1370 
1371 		case APM_NORMAL_RESUME:
1372 		case APM_CRITICAL_RESUME:
1373 		case APM_STANDBY_RESUME:
1374 			ignore_sys_suspend = 0;
1375 			last_resume = jiffies;
1376 			ignore_bounce = 1;
1377 			if ((event != APM_NORMAL_RESUME)
1378 			    || (ignore_normal_resume == 0)) {
1379 				dpm_resume_end(PMSG_RESUME);
1380 				queue_event(event, NULL);
1381 			}
1382 			ignore_normal_resume = 0;
1383 			break;
1384 
1385 		case APM_CAPABILITY_CHANGE:
1386 		case APM_LOW_BATTERY:
1387 		case APM_POWER_STATUS_CHANGE:
1388 			queue_event(event, NULL);
1389 			/* If needed, notify drivers here */
1390 			break;
1391 
1392 		case APM_UPDATE_TIME:
1393 			break;
1394 
1395 		case APM_CRITICAL_SUSPEND:
1396 			/*
1397 			 * We are not allowed to reject a critical suspend.
1398 			 */
1399 			(void)suspend(0);
1400 			break;
1401 		}
1402 	}
1403 }
1404 
1405 static void apm_event_handler(void)
1406 {
1407 	static int pending_count = 4;
1408 	int err;
1409 
1410 	if ((standbys_pending > 0) || (suspends_pending > 0)) {
1411 		if ((apm_info.connection_version > 0x100) &&
1412 		    (pending_count-- <= 0)) {
1413 			pending_count = 4;
1414 			if (debug)
1415 				printk(KERN_DEBUG "apm: setting state busy\n");
1416 			err = set_system_power_state(APM_STATE_BUSY);
1417 			if (err)
1418 				apm_error("busy", err);
1419 		}
1420 	} else
1421 		pending_count = 4;
1422 	check_events();
1423 }
1424 
1425 /*
1426  * This is the APM thread main loop.
1427  */
1428 
1429 static void apm_mainloop(void)
1430 {
1431 	DECLARE_WAITQUEUE(wait, current);
1432 
1433 	add_wait_queue(&apm_waitqueue, &wait);
1434 	set_current_state(TASK_INTERRUPTIBLE);
1435 	for (;;) {
1436 		schedule_timeout(APM_CHECK_TIMEOUT);
1437 		if (kthread_should_stop())
1438 			break;
1439 		/*
1440 		 * Ok, check all events, check for idle (and mark us sleeping
1441 		 * so as not to count towards the load average)..
1442 		 */
1443 		set_current_state(TASK_INTERRUPTIBLE);
1444 		apm_event_handler();
1445 	}
1446 	remove_wait_queue(&apm_waitqueue, &wait);
1447 }
1448 
1449 static int check_apm_user(struct apm_user *as, const char *func)
1450 {
1451 	if (as == NULL || as->magic != APM_BIOS_MAGIC) {
1452 		pr_err("%s passed bad filp\n", func);
1453 		return 1;
1454 	}
1455 	return 0;
1456 }
1457 
1458 static ssize_t do_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
1459 {
1460 	struct apm_user *as;
1461 	int i;
1462 	apm_event_t event;
1463 
1464 	as = fp->private_data;
1465 	if (check_apm_user(as, "read"))
1466 		return -EIO;
1467 	if ((int)count < sizeof(apm_event_t))
1468 		return -EINVAL;
1469 	if ((queue_empty(as)) && (fp->f_flags & O_NONBLOCK))
1470 		return -EAGAIN;
1471 	wait_event_interruptible(apm_waitqueue, !queue_empty(as));
1472 	i = count;
1473 	while ((i >= sizeof(event)) && !queue_empty(as)) {
1474 		event = get_queued_event(as);
1475 		if (copy_to_user(buf, &event, sizeof(event))) {
1476 			if (i < count)
1477 				break;
1478 			return -EFAULT;
1479 		}
1480 		switch (event) {
1481 		case APM_SYS_SUSPEND:
1482 		case APM_USER_SUSPEND:
1483 			as->suspends_read++;
1484 			break;
1485 
1486 		case APM_SYS_STANDBY:
1487 		case APM_USER_STANDBY:
1488 			as->standbys_read++;
1489 			break;
1490 		}
1491 		buf += sizeof(event);
1492 		i -= sizeof(event);
1493 	}
1494 	if (i < count)
1495 		return count - i;
1496 	if (signal_pending(current))
1497 		return -ERESTARTSYS;
1498 	return 0;
1499 }
1500 
1501 static unsigned int do_poll(struct file *fp, poll_table *wait)
1502 {
1503 	struct apm_user *as;
1504 
1505 	as = fp->private_data;
1506 	if (check_apm_user(as, "poll"))
1507 		return 0;
1508 	poll_wait(fp, &apm_waitqueue, wait);
1509 	if (!queue_empty(as))
1510 		return POLLIN | POLLRDNORM;
1511 	return 0;
1512 }
1513 
1514 static long do_ioctl(struct file *filp, u_int cmd, u_long arg)
1515 {
1516 	struct apm_user *as;
1517 	int ret;
1518 
1519 	as = filp->private_data;
1520 	if (check_apm_user(as, "ioctl"))
1521 		return -EIO;
1522 	if (!as->suser || !as->writer)
1523 		return -EPERM;
1524 	switch (cmd) {
1525 	case APM_IOC_STANDBY:
1526 		mutex_lock(&apm_mutex);
1527 		if (as->standbys_read > 0) {
1528 			as->standbys_read--;
1529 			as->standbys_pending--;
1530 			standbys_pending--;
1531 		} else
1532 			queue_event(APM_USER_STANDBY, as);
1533 		if (standbys_pending <= 0)
1534 			standby();
1535 		mutex_unlock(&apm_mutex);
1536 		break;
1537 	case APM_IOC_SUSPEND:
1538 		mutex_lock(&apm_mutex);
1539 		if (as->suspends_read > 0) {
1540 			as->suspends_read--;
1541 			as->suspends_pending--;
1542 			suspends_pending--;
1543 		} else
1544 			queue_event(APM_USER_SUSPEND, as);
1545 		if (suspends_pending <= 0) {
1546 			ret = suspend(1);
1547 			mutex_unlock(&apm_mutex);
1548 		} else {
1549 			as->suspend_wait = 1;
1550 			mutex_unlock(&apm_mutex);
1551 			wait_event_interruptible(apm_suspend_waitqueue,
1552 					as->suspend_wait == 0);
1553 			ret = as->suspend_result;
1554 		}
1555 		return ret;
1556 	default:
1557 		return -ENOTTY;
1558 	}
1559 	return 0;
1560 }
1561 
1562 static int do_release(struct inode *inode, struct file *filp)
1563 {
1564 	struct apm_user *as;
1565 
1566 	as = filp->private_data;
1567 	if (check_apm_user(as, "release"))
1568 		return 0;
1569 	filp->private_data = NULL;
1570 	if (as->standbys_pending > 0) {
1571 		standbys_pending -= as->standbys_pending;
1572 		if (standbys_pending <= 0)
1573 			standby();
1574 	}
1575 	if (as->suspends_pending > 0) {
1576 		suspends_pending -= as->suspends_pending;
1577 		if (suspends_pending <= 0)
1578 			(void) suspend(1);
1579 	}
1580 	spin_lock(&user_list_lock);
1581 	if (user_list == as)
1582 		user_list = as->next;
1583 	else {
1584 		struct apm_user *as1;
1585 
1586 		for (as1 = user_list;
1587 		     (as1 != NULL) && (as1->next != as);
1588 		     as1 = as1->next)
1589 			;
1590 		if (as1 == NULL)
1591 			pr_err("filp not in user list\n");
1592 		else
1593 			as1->next = as->next;
1594 	}
1595 	spin_unlock(&user_list_lock);
1596 	kfree(as);
1597 	return 0;
1598 }
1599 
1600 static int do_open(struct inode *inode, struct file *filp)
1601 {
1602 	struct apm_user *as;
1603 
1604 	as = kmalloc(sizeof(*as), GFP_KERNEL);
1605 	if (as == NULL)
1606 		return -ENOMEM;
1607 
1608 	as->magic = APM_BIOS_MAGIC;
1609 	as->event_tail = as->event_head = 0;
1610 	as->suspends_pending = as->standbys_pending = 0;
1611 	as->suspends_read = as->standbys_read = 0;
1612 	/*
1613 	 * XXX - this is a tiny bit broken, when we consider BSD
1614 	 * process accounting. If the device is opened by root, we
1615 	 * instantly flag that we used superuser privs. Who knows,
1616 	 * we might close the device immediately without doing a
1617 	 * privileged operation -- cevans
1618 	 */
1619 	as->suser = capable(CAP_SYS_ADMIN);
1620 	as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
1621 	as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
1622 	spin_lock(&user_list_lock);
1623 	as->next = user_list;
1624 	user_list = as;
1625 	spin_unlock(&user_list_lock);
1626 	filp->private_data = as;
1627 	return 0;
1628 }
1629 
1630 static int proc_apm_show(struct seq_file *m, void *v)
1631 {
1632 	unsigned short	bx;
1633 	unsigned short	cx;
1634 	unsigned short	dx;
1635 	int		error;
1636 	unsigned short  ac_line_status = 0xff;
1637 	unsigned short  battery_status = 0xff;
1638 	unsigned short  battery_flag   = 0xff;
1639 	int		percentage     = -1;
1640 	int             time_units     = -1;
1641 	char            *units         = "?";
1642 
1643 	if ((num_online_cpus() == 1) &&
1644 	    !(error = apm_get_power_status(&bx, &cx, &dx))) {
1645 		ac_line_status = (bx >> 8) & 0xff;
1646 		battery_status = bx & 0xff;
1647 		if ((cx & 0xff) != 0xff)
1648 			percentage = cx & 0xff;
1649 
1650 		if (apm_info.connection_version > 0x100) {
1651 			battery_flag = (cx >> 8) & 0xff;
1652 			if (dx != 0xffff) {
1653 				units = (dx & 0x8000) ? "min" : "sec";
1654 				time_units = dx & 0x7fff;
1655 			}
1656 		}
1657 	}
1658 	/* Arguments, with symbols from linux/apm_bios.h.  Information is
1659 	   from the Get Power Status (0x0a) call unless otherwise noted.
1660 
1661 	   0) Linux driver version (this will change if format changes)
1662 	   1) APM BIOS Version.  Usually 1.0, 1.1 or 1.2.
1663 	   2) APM flags from APM Installation Check (0x00):
1664 	      bit 0: APM_16_BIT_SUPPORT
1665 	      bit 1: APM_32_BIT_SUPPORT
1666 	      bit 2: APM_IDLE_SLOWS_CLOCK
1667 	      bit 3: APM_BIOS_DISABLED
1668 	      bit 4: APM_BIOS_DISENGAGED
1669 	   3) AC line status
1670 	      0x00: Off-line
1671 	      0x01: On-line
1672 	      0x02: On backup power (BIOS >= 1.1 only)
1673 	      0xff: Unknown
1674 	   4) Battery status
1675 	      0x00: High
1676 	      0x01: Low
1677 	      0x02: Critical
1678 	      0x03: Charging
1679 	      0x04: Selected battery not present (BIOS >= 1.2 only)
1680 	      0xff: Unknown
1681 	   5) Battery flag
1682 	      bit 0: High
1683 	      bit 1: Low
1684 	      bit 2: Critical
1685 	      bit 3: Charging
1686 	      bit 7: No system battery
1687 	      0xff: Unknown
1688 	   6) Remaining battery life (percentage of charge):
1689 	      0-100: valid
1690 	      -1: Unknown
1691 	   7) Remaining battery life (time units):
1692 	      Number of remaining minutes or seconds
1693 	      -1: Unknown
1694 	   8) min = minutes; sec = seconds */
1695 
1696 	seq_printf(m, "%s %d.%d 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
1697 		   driver_version,
1698 		   (apm_info.bios.version >> 8) & 0xff,
1699 		   apm_info.bios.version & 0xff,
1700 		   apm_info.bios.flags,
1701 		   ac_line_status,
1702 		   battery_status,
1703 		   battery_flag,
1704 		   percentage,
1705 		   time_units,
1706 		   units);
1707 	return 0;
1708 }
1709 
1710 static int proc_apm_open(struct inode *inode, struct file *file)
1711 {
1712 	return single_open(file, proc_apm_show, NULL);
1713 }
1714 
1715 static const struct file_operations apm_file_ops = {
1716 	.owner		= THIS_MODULE,
1717 	.open		= proc_apm_open,
1718 	.read		= seq_read,
1719 	.llseek		= seq_lseek,
1720 	.release	= single_release,
1721 };
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 struct dmi_system_id __initdata apm_dmi_table[] = {
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 || paravirt_enabled() || 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_table(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("apm", 0, NULL, &apm_file_ops);
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 		original_pm_idle = pm_idle;
2385 		pm_idle  = apm_cpu_idle;
2386 		set_pm_idle = 1;
2387 	}
2388 
2389 	return 0;
2390 }
2391 
2392 static void __exit apm_exit(void)
2393 {
2394 	int error;
2395 
2396 	if (set_pm_idle) {
2397 		pm_idle = original_pm_idle;
2398 		/*
2399 		 * We are about to unload the current idle thread pm callback
2400 		 * (pm_idle), Wait for all processors to update cached/local
2401 		 * copies of pm_idle before proceeding.
2402 		 */
2403 		kick_all_cpus_sync();
2404 	}
2405 	if (((apm_info.bios.flags & APM_BIOS_DISENGAGED) == 0)
2406 	    && (apm_info.connection_version > 0x0100)) {
2407 		error = apm_engage_power_management(APM_DEVICE_ALL, 0);
2408 		if (error)
2409 			apm_error("disengage power management", error);
2410 	}
2411 	misc_deregister(&apm_device);
2412 	remove_proc_entry("apm", NULL);
2413 	if (power_off)
2414 		pm_power_off = NULL;
2415 	if (kapmd_task) {
2416 		kthread_stop(kapmd_task);
2417 		kapmd_task = NULL;
2418 	}
2419 }
2420 
2421 module_init(apm_init);
2422 module_exit(apm_exit);
2423 
2424 MODULE_AUTHOR("Stephen Rothwell");
2425 MODULE_DESCRIPTION("Advanced Power Management");
2426 MODULE_LICENSE("GPL");
2427 module_param(debug, bool, 0644);
2428 MODULE_PARM_DESC(debug, "Enable debug mode");
2429 module_param(power_off, bool, 0444);
2430 MODULE_PARM_DESC(power_off, "Enable power off");
2431 module_param(bounce_interval, int, 0444);
2432 MODULE_PARM_DESC(bounce_interval,
2433 		"Set the number of ticks to ignore suspend bounces");
2434 module_param(allow_ints, bool, 0444);
2435 MODULE_PARM_DESC(allow_ints, "Allow interrupts during BIOS calls");
2436 module_param(broken_psr, bool, 0444);
2437 MODULE_PARM_DESC(broken_psr, "BIOS has a broken GetPowerStatus call");
2438 module_param(realmode_power_off, bool, 0444);
2439 MODULE_PARM_DESC(realmode_power_off,
2440 		"Switch to real mode before powering off");
2441 module_param(idle_threshold, int, 0444);
2442 MODULE_PARM_DESC(idle_threshold,
2443 	"System idle percentage above which to make APM BIOS idle calls");
2444 module_param(idle_period, int, 0444);
2445 MODULE_PARM_DESC(idle_period,
2446 	"Period (in sec/100) over which to caculate the idle percentage");
2447 module_param(smp, bool, 0444);
2448 MODULE_PARM_DESC(smp,
2449 	"Set this to enable APM use on an SMP platform. Use with caution on older systems");
2450 MODULE_ALIAS_MISCDEV(APM_MINOR_DEV);
2451