xref: /openbmc/linux/arch/x86/kernel/apm_32.c (revision b627b4ed)
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/smp_lock.h>
208 #include <linux/types.h>
209 #include <linux/stddef.h>
210 #include <linux/timer.h>
211 #include <linux/fcntl.h>
212 #include <linux/slab.h>
213 #include <linux/stat.h>
214 #include <linux/proc_fs.h>
215 #include <linux/seq_file.h>
216 #include <linux/miscdevice.h>
217 #include <linux/apm_bios.h>
218 #include <linux/init.h>
219 #include <linux/time.h>
220 #include <linux/sched.h>
221 #include <linux/pm.h>
222 #include <linux/capability.h>
223 #include <linux/device.h>
224 #include <linux/kernel.h>
225 #include <linux/freezer.h>
226 #include <linux/smp.h>
227 #include <linux/dmi.h>
228 #include <linux/suspend.h>
229 #include <linux/kthread.h>
230 #include <linux/jiffies.h>
231 
232 #include <asm/system.h>
233 #include <asm/uaccess.h>
234 #include <asm/desc.h>
235 #include <asm/i8253.h>
236 #include <asm/olpc.h>
237 #include <asm/paravirt.h>
238 #include <asm/reboot.h>
239 
240 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
241 extern int (*console_blank_hook)(int);
242 #endif
243 
244 /*
245  * The apm_bios device is one of the misc char devices.
246  * This is its minor number.
247  */
248 #define	APM_MINOR_DEV	134
249 
250 /*
251  * See Documentation/Config.help for the configuration options.
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 #define DEFAULT_IDLE_THRESHOLD	95
364 #else
365 #define DEFAULT_IDLE_THRESHOLD	100
366 #endif
367 #define DEFAULT_IDLE_PERIOD	(100 / 3)
368 
369 /*
370  * Local variables
371  */
372 static struct {
373 	unsigned long	offset;
374 	unsigned short	segment;
375 } apm_bios_entry;
376 static int clock_slowed;
377 static int idle_threshold __read_mostly = DEFAULT_IDLE_THRESHOLD;
378 static int idle_period __read_mostly = DEFAULT_IDLE_PERIOD;
379 static int set_pm_idle;
380 static int suspends_pending;
381 static int standbys_pending;
382 static int ignore_sys_suspend;
383 static int ignore_normal_resume;
384 static int bounce_interval __read_mostly = DEFAULT_BOUNCE_INTERVAL;
385 
386 static int debug __read_mostly;
387 static int smp __read_mostly;
388 static int apm_disabled = -1;
389 #ifdef CONFIG_SMP
390 static int power_off;
391 #else
392 static int power_off = 1;
393 #endif
394 static int realmode_power_off;
395 #ifdef CONFIG_APM_ALLOW_INTS
396 static int allow_ints = 1;
397 #else
398 static int allow_ints;
399 #endif
400 static int broken_psr;
401 
402 static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
403 static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
404 static struct apm_user *user_list;
405 static DEFINE_SPINLOCK(user_list_lock);
406 static const struct desc_struct	bad_bios_desc = { { { 0, 0x00409200 } } };
407 
408 static const char driver_version[] = "1.16ac";	/* no spaces */
409 
410 static struct task_struct *kapmd_task;
411 
412 /*
413  *	APM event names taken from the APM 1.2 specification. These are
414  *	the message codes that the BIOS uses to tell us about events
415  */
416 static const char * const apm_event_name[] = {
417 	"system standby",
418 	"system suspend",
419 	"normal resume",
420 	"critical resume",
421 	"low battery",
422 	"power status change",
423 	"update time",
424 	"critical suspend",
425 	"user standby",
426 	"user suspend",
427 	"system standby resume",
428 	"capabilities change"
429 };
430 #define NR_APM_EVENT_NAME ARRAY_SIZE(apm_event_name)
431 
432 typedef struct lookup_t {
433 	int	key;
434 	char 	*msg;
435 } lookup_t;
436 
437 /*
438  *	The BIOS returns a set of standard error codes in AX when the
439  *	carry flag is set.
440  */
441 
442 static const lookup_t error_table[] = {
443 /* N/A	{ APM_SUCCESS,		"Operation succeeded" }, */
444 	{ APM_DISABLED,		"Power management disabled" },
445 	{ APM_CONNECTED,	"Real mode interface already connected" },
446 	{ APM_NOT_CONNECTED,	"Interface not connected" },
447 	{ APM_16_CONNECTED,	"16 bit interface already connected" },
448 /* N/A	{ APM_16_UNSUPPORTED,	"16 bit interface not supported" }, */
449 	{ APM_32_CONNECTED,	"32 bit interface already connected" },
450 	{ APM_32_UNSUPPORTED,	"32 bit interface not supported" },
451 	{ APM_BAD_DEVICE,	"Unrecognized device ID" },
452 	{ APM_BAD_PARAM,	"Parameter out of range" },
453 	{ APM_NOT_ENGAGED,	"Interface not engaged" },
454 	{ APM_BAD_FUNCTION,     "Function not supported" },
455 	{ APM_RESUME_DISABLED,	"Resume timer disabled" },
456 	{ APM_BAD_STATE,	"Unable to enter requested state" },
457 /* N/A	{ APM_NO_EVENTS,	"No events pending" }, */
458 	{ APM_NO_ERROR,		"BIOS did not set a return code" },
459 	{ APM_NOT_PRESENT,	"No APM present" }
460 };
461 #define ERROR_COUNT	ARRAY_SIZE(error_table)
462 
463 /**
464  *	apm_error	-	display an APM error
465  *	@str: information string
466  *	@err: APM BIOS return code
467  *
468  *	Write a meaningful log entry to the kernel log in the event of
469  *	an APM error.  Note that this also handles (negative) kernel errors.
470  */
471 
472 static void apm_error(char *str, int err)
473 {
474 	int i;
475 
476 	for (i = 0; i < ERROR_COUNT; i++)
477 		if (error_table[i].key == err)
478 			break;
479 	if (i < ERROR_COUNT)
480 		printk(KERN_NOTICE "apm: %s: %s\n", str, error_table[i].msg);
481 	else if (err < 0)
482 		printk(KERN_NOTICE "apm: %s: linux error code %i\n", str, err);
483 	else
484 		printk(KERN_NOTICE "apm: %s: unknown error code %#2.2x\n",
485 		       str, err);
486 }
487 
488 /*
489  * These are the actual BIOS calls.  Depending on APM_ZERO_SEGS and
490  * apm_info.allow_ints, we are being really paranoid here!  Not only
491  * are interrupts disabled, but all the segment registers (except SS)
492  * are saved and zeroed this means that if the BIOS tries to reference
493  * any data without explicitly loading the segment registers, the kernel
494  * will fault immediately rather than have some unforeseen circumstances
495  * for the rest of the kernel.  And it will be very obvious!  :-) Doing
496  * this depends on CS referring to the same physical memory as DS so that
497  * DS can be zeroed before the call. Unfortunately, we can't do anything
498  * about the stack segment/pointer.  Also, we tell the compiler that
499  * everything could change.
500  *
501  * Also, we KNOW that for the non error case of apm_bios_call, there
502  * is no useful data returned in the low order 8 bits of eax.
503  */
504 
505 static inline unsigned long __apm_irq_save(void)
506 {
507 	unsigned long flags;
508 	local_save_flags(flags);
509 	if (apm_info.allow_ints) {
510 		if (irqs_disabled_flags(flags))
511 			local_irq_enable();
512 	} else
513 		local_irq_disable();
514 
515 	return flags;
516 }
517 
518 #define apm_irq_save(flags) \
519 	do { flags = __apm_irq_save(); } while (0)
520 
521 static inline void apm_irq_restore(unsigned long flags)
522 {
523 	if (irqs_disabled_flags(flags))
524 		local_irq_disable();
525 	else if (irqs_disabled())
526 		local_irq_enable();
527 }
528 
529 #ifdef APM_ZERO_SEGS
530 #	define APM_DECL_SEGS \
531 		unsigned int saved_fs; unsigned int saved_gs;
532 #	define APM_DO_SAVE_SEGS \
533 		savesegment(fs, saved_fs); savesegment(gs, saved_gs)
534 #	define APM_DO_RESTORE_SEGS \
535 		loadsegment(fs, saved_fs); loadsegment(gs, saved_gs)
536 #else
537 #	define APM_DECL_SEGS
538 #	define APM_DO_SAVE_SEGS
539 #	define APM_DO_RESTORE_SEGS
540 #endif
541 
542 struct apm_bios_call {
543 	u32 func;
544 	/* In and out */
545 	u32 ebx;
546 	u32 ecx;
547 	/* Out only */
548 	u32 eax;
549 	u32 edx;
550 	u32 esi;
551 
552 	/* Error: -ENOMEM, or bits 8-15 of eax */
553 	int err;
554 };
555 
556 /**
557  *	__apm_bios_call - Make an APM BIOS 32bit call
558  *	@_call: pointer to struct apm_bios_call.
559  *
560  *	Make an APM call using the 32bit protected mode interface. The
561  *	caller is responsible for knowing if APM BIOS is configured and
562  *	enabled. This call can disable interrupts for a long period of
563  *	time on some laptops.  The return value is in AH and the carry
564  *	flag is loaded into AL.  If there is an error, then the error
565  *	code is returned in AH (bits 8-15 of eax) and this function
566  *	returns non-zero.
567  *
568  *	Note: this makes the call on the current CPU.
569  */
570 static long __apm_bios_call(void *_call)
571 {
572 	APM_DECL_SEGS
573 	unsigned long		flags;
574 	int			cpu;
575 	struct desc_struct	save_desc_40;
576 	struct desc_struct	*gdt;
577 	struct apm_bios_call	*call = _call;
578 
579 	cpu = get_cpu();
580 	BUG_ON(cpu != 0);
581 	gdt = get_cpu_gdt_table(cpu);
582 	save_desc_40 = gdt[0x40 / 8];
583 	gdt[0x40 / 8] = bad_bios_desc;
584 
585 	apm_irq_save(flags);
586 	APM_DO_SAVE_SEGS;
587 	apm_bios_call_asm(call->func, call->ebx, call->ecx,
588 			  &call->eax, &call->ebx, &call->ecx, &call->edx,
589 			  &call->esi);
590 	APM_DO_RESTORE_SEGS;
591 	apm_irq_restore(flags);
592 	gdt[0x40 / 8] = save_desc_40;
593 	put_cpu();
594 
595 	return call->eax & 0xff;
596 }
597 
598 /* Run __apm_bios_call or __apm_bios_call_simple on CPU 0 */
599 static int on_cpu0(long (*fn)(void *), struct apm_bios_call *call)
600 {
601 	int ret;
602 
603 	/* Don't bother with work_on_cpu in the common case, so we don't
604 	 * have to worry about OOM or overhead. */
605 	if (get_cpu() == 0) {
606 		ret = fn(call);
607 		put_cpu();
608 	} else {
609 		put_cpu();
610 		ret = work_on_cpu(0, fn, call);
611 	}
612 
613 	/* work_on_cpu can fail with -ENOMEM */
614 	if (ret < 0)
615 		call->err = ret;
616 	else
617 		call->err = (call->eax >> 8) & 0xff;
618 
619 	return ret;
620 }
621 
622 /**
623  *	apm_bios_call	-	Make an APM BIOS 32bit call (on CPU 0)
624  *	@call: the apm_bios_call registers.
625  *
626  *	If there is an error, it is returned in @call.err.
627  */
628 static int apm_bios_call(struct apm_bios_call *call)
629 {
630 	return on_cpu0(__apm_bios_call, call);
631 }
632 
633 /**
634  *	__apm_bios_call_simple - Make an APM BIOS 32bit call (on CPU 0)
635  *	@_call: pointer to struct apm_bios_call.
636  *
637  *	Make a BIOS call that returns one value only, or just status.
638  *	If there is an error, then the error code is returned in AH
639  *	(bits 8-15 of eax) and this function returns non-zero (it can
640  *	also return -ENOMEM). This is used for simpler BIOS operations.
641  *	This call may hold interrupts off for a long time on some laptops.
642  *
643  *	Note: this makes the call on the current CPU.
644  */
645 static long __apm_bios_call_simple(void *_call)
646 {
647 	u8			error;
648 	APM_DECL_SEGS
649 	unsigned long		flags;
650 	int			cpu;
651 	struct desc_struct	save_desc_40;
652 	struct desc_struct	*gdt;
653 	struct apm_bios_call	*call = _call;
654 
655 	cpu = get_cpu();
656 	BUG_ON(cpu != 0);
657 	gdt = get_cpu_gdt_table(cpu);
658 	save_desc_40 = gdt[0x40 / 8];
659 	gdt[0x40 / 8] = bad_bios_desc;
660 
661 	apm_irq_save(flags);
662 	APM_DO_SAVE_SEGS;
663 	error = apm_bios_call_simple_asm(call->func, call->ebx, call->ecx,
664 					 &call->eax);
665 	APM_DO_RESTORE_SEGS;
666 	apm_irq_restore(flags);
667 	gdt[0x40 / 8] = save_desc_40;
668 	put_cpu();
669 	return error;
670 }
671 
672 /**
673  *	apm_bios_call_simple	-	make a simple APM BIOS 32bit call
674  *	@func: APM function to invoke
675  *	@ebx_in: EBX register value for BIOS call
676  *	@ecx_in: ECX register value for BIOS call
677  *	@eax: EAX register on return from the BIOS call
678  *	@err: bits
679  *
680  *	Make a BIOS call that returns one value only, or just status.
681  *	If there is an error, then the error code is returned in @err
682  *	and this function returns non-zero. This is used for simpler
683  *	BIOS operations.  This call may hold interrupts off for a long
684  *	time on some laptops.
685  */
686 static int apm_bios_call_simple(u32 func, u32 ebx_in, u32 ecx_in, u32 *eax,
687 				int *err)
688 {
689 	struct apm_bios_call call;
690 	int ret;
691 
692 	call.func = func;
693 	call.ebx = ebx_in;
694 	call.ecx = ecx_in;
695 
696 	ret = on_cpu0(__apm_bios_call_simple, &call);
697 	*eax = call.eax;
698 	*err = call.err;
699 	return ret;
700 }
701 
702 /**
703  *	apm_driver_version	-	APM driver version
704  *	@val:	loaded with the APM version on return
705  *
706  *	Retrieve the APM version supported by the BIOS. This is only
707  *	supported for APM 1.1 or higher. An error indicates APM 1.0 is
708  *	probably present.
709  *
710  *	On entry val should point to a value indicating the APM driver
711  *	version with the high byte being the major and the low byte the
712  *	minor number both in BCD
713  *
714  *	On return it will hold the BIOS revision supported in the
715  *	same format.
716  */
717 
718 static int apm_driver_version(u_short *val)
719 {
720 	u32 eax;
721 	int err;
722 
723 	if (apm_bios_call_simple(APM_FUNC_VERSION, 0, *val, &eax, &err))
724 		return err;
725 	*val = eax;
726 	return APM_SUCCESS;
727 }
728 
729 /**
730  *	apm_get_event	-	get an APM event from the BIOS
731  *	@event: pointer to the event
732  *	@info: point to the event information
733  *
734  *	The APM BIOS provides a polled information for event
735  *	reporting. The BIOS expects to be polled at least every second
736  *	when events are pending. When a message is found the caller should
737  *	poll until no more messages are present.  However, this causes
738  *	problems on some laptops where a suspend event notification is
739  *	not cleared until it is acknowledged.
740  *
741  *	Additional information is returned in the info pointer, providing
742  *	that APM 1.2 is in use. If no messges are pending the value 0x80
743  *	is returned (No power management events pending).
744  */
745 static int apm_get_event(apm_event_t *event, apm_eventinfo_t *info)
746 {
747 	struct apm_bios_call call;
748 
749 	call.func = APM_FUNC_GET_EVENT;
750 	call.ebx = call.ecx = 0;
751 
752 	if (apm_bios_call(&call))
753 		return call.err;
754 
755 	*event = call.ebx;
756 	if (apm_info.connection_version < 0x0102)
757 		*info = ~0; /* indicate info not valid */
758 	else
759 		*info = call.ecx;
760 	return APM_SUCCESS;
761 }
762 
763 /**
764  *	set_power_state	-	set the power management state
765  *	@what: which items to transition
766  *	@state: state to transition to
767  *
768  *	Request an APM change of state for one or more system devices. The
769  *	processor state must be transitioned last of all. what holds the
770  *	class of device in the upper byte and the device number (0xFF for
771  *	all) for the object to be transitioned.
772  *
773  *	The state holds the state to transition to, which may in fact
774  *	be an acceptance of a BIOS requested state change.
775  */
776 
777 static int set_power_state(u_short what, u_short state)
778 {
779 	u32 eax;
780 	int err;
781 
782 	if (apm_bios_call_simple(APM_FUNC_SET_STATE, what, state, &eax, &err))
783 		return err;
784 	return APM_SUCCESS;
785 }
786 
787 /**
788  *	set_system_power_state - set system wide power state
789  *	@state: which state to enter
790  *
791  *	Transition the entire system into a new APM power state.
792  */
793 
794 static int set_system_power_state(u_short state)
795 {
796 	return set_power_state(APM_DEVICE_ALL, state);
797 }
798 
799 /**
800  *	apm_do_idle	-	perform power saving
801  *
802  *	This function notifies the BIOS that the processor is (in the view
803  *	of the OS) idle. It returns -1 in the event that the BIOS refuses
804  *	to handle the idle request. On a success the function returns 1
805  *	if the BIOS did clock slowing or 0 otherwise.
806  */
807 
808 static int apm_do_idle(void)
809 {
810 	u32 eax;
811 	u8 ret = 0;
812 	int idled = 0;
813 	int polling;
814 	int err;
815 
816 	polling = !!(current_thread_info()->status & TS_POLLING);
817 	if (polling) {
818 		current_thread_info()->status &= ~TS_POLLING;
819 		/*
820 		 * TS_POLLING-cleared state must be visible before we
821 		 * test NEED_RESCHED:
822 		 */
823 		smp_mb();
824 	}
825 	if (!need_resched()) {
826 		idled = 1;
827 		ret = apm_bios_call_simple(APM_FUNC_IDLE, 0, 0, &eax, &err);
828 	}
829 	if (polling)
830 		current_thread_info()->status |= TS_POLLING;
831 
832 	if (!idled)
833 		return 0;
834 
835 	if (ret) {
836 		static unsigned long t;
837 
838 		/* This always fails on some SMP boards running UP kernels.
839 		 * Only report the failure the first 5 times.
840 		 */
841 		if (++t < 5) {
842 			printk(KERN_DEBUG "apm_do_idle failed (%d)\n", err);
843 			t = jiffies;
844 		}
845 		return -1;
846 	}
847 	clock_slowed = (apm_info.bios.flags & APM_IDLE_SLOWS_CLOCK) != 0;
848 	return clock_slowed;
849 }
850 
851 /**
852  *	apm_do_busy	-	inform the BIOS the CPU is busy
853  *
854  *	Request that the BIOS brings the CPU back to full performance.
855  */
856 
857 static void apm_do_busy(void)
858 {
859 	u32 dummy;
860 	int err;
861 
862 	if (clock_slowed || ALWAYS_CALL_BUSY) {
863 		(void)apm_bios_call_simple(APM_FUNC_BUSY, 0, 0, &dummy, &err);
864 		clock_slowed = 0;
865 	}
866 }
867 
868 /*
869  * If no process has really been interested in
870  * the CPU for some time, we want to call BIOS
871  * power management - we probably want
872  * to conserve power.
873  */
874 #define IDLE_CALC_LIMIT	(HZ * 100)
875 #define IDLE_LEAKY_MAX	16
876 
877 static void (*original_pm_idle)(void) __read_mostly;
878 
879 /**
880  * apm_cpu_idle		-	cpu idling for APM capable Linux
881  *
882  * This is the idling function the kernel executes when APM is available. It
883  * tries to do BIOS powermanagement based on the average system idle time.
884  * Furthermore it calls the system default idle routine.
885  */
886 
887 static void apm_cpu_idle(void)
888 {
889 	static int use_apm_idle; /* = 0 */
890 	static unsigned int last_jiffies; /* = 0 */
891 	static unsigned int last_stime; /* = 0 */
892 
893 	int apm_idle_done = 0;
894 	unsigned int jiffies_since_last_check = jiffies - last_jiffies;
895 	unsigned int bucket;
896 
897 recalc:
898 	if (jiffies_since_last_check > IDLE_CALC_LIMIT) {
899 		use_apm_idle = 0;
900 		last_jiffies = jiffies;
901 		last_stime = current->stime;
902 	} else if (jiffies_since_last_check > idle_period) {
903 		unsigned int idle_percentage;
904 
905 		idle_percentage = current->stime - last_stime;
906 		idle_percentage *= 100;
907 		idle_percentage /= jiffies_since_last_check;
908 		use_apm_idle = (idle_percentage > idle_threshold);
909 		if (apm_info.forbid_idle)
910 			use_apm_idle = 0;
911 		last_jiffies = jiffies;
912 		last_stime = current->stime;
913 	}
914 
915 	bucket = IDLE_LEAKY_MAX;
916 
917 	while (!need_resched()) {
918 		if (use_apm_idle) {
919 			unsigned int t;
920 
921 			t = jiffies;
922 			switch (apm_do_idle()) {
923 			case 0:
924 				apm_idle_done = 1;
925 				if (t != jiffies) {
926 					if (bucket) {
927 						bucket = IDLE_LEAKY_MAX;
928 						continue;
929 					}
930 				} else if (bucket) {
931 					bucket--;
932 					continue;
933 				}
934 				break;
935 			case 1:
936 				apm_idle_done = 1;
937 				break;
938 			default: /* BIOS refused */
939 				break;
940 			}
941 		}
942 		if (original_pm_idle)
943 			original_pm_idle();
944 		else
945 			default_idle();
946 		local_irq_disable();
947 		jiffies_since_last_check = jiffies - last_jiffies;
948 		if (jiffies_since_last_check > idle_period)
949 			goto recalc;
950 	}
951 
952 	if (apm_idle_done)
953 		apm_do_busy();
954 
955 	local_irq_enable();
956 }
957 
958 /**
959  *	apm_power_off	-	ask the BIOS to power off
960  *
961  *	Handle the power off sequence. This is the one piece of code we
962  *	will execute even on SMP machines. In order to deal with BIOS
963  *	bugs we support real mode APM BIOS power off calls. We also make
964  *	the SMP call on CPU0 as some systems will only honour this call
965  *	on their first cpu.
966  */
967 
968 static void apm_power_off(void)
969 {
970 	unsigned char po_bios_call[] = {
971 		0xb8, 0x00, 0x10,	/* movw  $0x1000,ax  */
972 		0x8e, 0xd0,		/* movw  ax,ss       */
973 		0xbc, 0x00, 0xf0,	/* movw  $0xf000,sp  */
974 		0xb8, 0x07, 0x53,	/* movw  $0x5307,ax  */
975 		0xbb, 0x01, 0x00,	/* movw  $0x0001,bx  */
976 		0xb9, 0x03, 0x00,	/* movw  $0x0003,cx  */
977 		0xcd, 0x15		/* int   $0x15       */
978 	};
979 
980 	/* Some bioses don't like being called from CPU != 0 */
981 	if (apm_info.realmode_power_off) {
982 		set_cpus_allowed_ptr(current, cpumask_of(0));
983 		machine_real_restart(po_bios_call, sizeof(po_bios_call));
984 	} else {
985 		(void)set_system_power_state(APM_STATE_OFF);
986 	}
987 }
988 
989 #ifdef CONFIG_APM_DO_ENABLE
990 
991 /**
992  *	apm_enable_power_management - enable BIOS APM power management
993  *	@enable: enable yes/no
994  *
995  *	Enable or disable the APM BIOS power services.
996  */
997 
998 static int apm_enable_power_management(int enable)
999 {
1000 	u32 eax;
1001 	int err;
1002 
1003 	if ((enable == 0) && (apm_info.bios.flags & APM_BIOS_DISENGAGED))
1004 		return APM_NOT_ENGAGED;
1005 	if (apm_bios_call_simple(APM_FUNC_ENABLE_PM, APM_DEVICE_BALL,
1006 				 enable, &eax, &err))
1007 		return err;
1008 	if (enable)
1009 		apm_info.bios.flags &= ~APM_BIOS_DISABLED;
1010 	else
1011 		apm_info.bios.flags |= APM_BIOS_DISABLED;
1012 	return APM_SUCCESS;
1013 }
1014 #endif
1015 
1016 /**
1017  *	apm_get_power_status	-	get current power state
1018  *	@status: returned status
1019  *	@bat: battery info
1020  *	@life: estimated life
1021  *
1022  *	Obtain the current power status from the APM BIOS. We return a
1023  *	status which gives the rough battery status, and current power
1024  *	source. The bat value returned give an estimate as a percentage
1025  *	of life and a status value for the battery. The estimated life
1026  *	if reported is a lifetime in secodnds/minutes at current powwer
1027  *	consumption.
1028  */
1029 
1030 static int apm_get_power_status(u_short *status, u_short *bat, u_short *life)
1031 {
1032 	struct apm_bios_call call;
1033 
1034 	call.func = APM_FUNC_GET_STATUS;
1035 	call.ebx = APM_DEVICE_ALL;
1036 	call.ecx = 0;
1037 
1038 	if (apm_info.get_power_status_broken)
1039 		return APM_32_UNSUPPORTED;
1040 	if (apm_bios_call(&call))
1041 		return call.err;
1042 	*status = call.ebx;
1043 	*bat = call.ecx;
1044 	if (apm_info.get_power_status_swabinminutes) {
1045 		*life = swab16((u16)call.edx);
1046 		*life |= 0x8000;
1047 	} else
1048 		*life = call.edx;
1049 	return APM_SUCCESS;
1050 }
1051 
1052 #if 0
1053 static int apm_get_battery_status(u_short which, u_short *status,
1054 				  u_short *bat, u_short *life, u_short *nbat)
1055 {
1056 	u32 eax;
1057 	u32 ebx;
1058 	u32 ecx;
1059 	u32 edx;
1060 	u32 esi;
1061 
1062 	if (apm_info.connection_version < 0x0102) {
1063 		/* pretend we only have one battery. */
1064 		if (which != 1)
1065 			return APM_BAD_DEVICE;
1066 		*nbat = 1;
1067 		return apm_get_power_status(status, bat, life);
1068 	}
1069 
1070 	if (apm_bios_call(APM_FUNC_GET_STATUS, (0x8000 | (which)), 0, &eax,
1071 			  &ebx, &ecx, &edx, &esi))
1072 		return (eax >> 8) & 0xff;
1073 	*status = ebx;
1074 	*bat = ecx;
1075 	*life = edx;
1076 	*nbat = esi;
1077 	return APM_SUCCESS;
1078 }
1079 #endif
1080 
1081 /**
1082  *	apm_engage_power_management	-	enable PM on a device
1083  *	@device: identity of device
1084  *	@enable: on/off
1085  *
1086  *	Activate or deactive power management on either a specific device
1087  *	or the entire system (%APM_DEVICE_ALL).
1088  */
1089 
1090 static int apm_engage_power_management(u_short device, int enable)
1091 {
1092 	u32 eax;
1093 	int err;
1094 
1095 	if ((enable == 0) && (device == APM_DEVICE_ALL)
1096 	    && (apm_info.bios.flags & APM_BIOS_DISABLED))
1097 		return APM_DISABLED;
1098 	if (apm_bios_call_simple(APM_FUNC_ENGAGE_PM, device, enable,
1099 				 &eax, &err))
1100 		return err;
1101 	if (device == APM_DEVICE_ALL) {
1102 		if (enable)
1103 			apm_info.bios.flags &= ~APM_BIOS_DISENGAGED;
1104 		else
1105 			apm_info.bios.flags |= APM_BIOS_DISENGAGED;
1106 	}
1107 	return APM_SUCCESS;
1108 }
1109 
1110 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1111 
1112 /**
1113  *	apm_console_blank	-	blank the display
1114  *	@blank: on/off
1115  *
1116  *	Attempt to blank the console, firstly by blanking just video device
1117  *	zero, and if that fails (some BIOSes don't support it) then it blanks
1118  *	all video devices. Typically the BIOS will do laptop backlight and
1119  *	monitor powerdown for us.
1120  */
1121 
1122 static int apm_console_blank(int blank)
1123 {
1124 	int error = APM_NOT_ENGAGED; /* silence gcc */
1125 	int i;
1126 	u_short state;
1127 	static const u_short dev[3] = { 0x100, 0x1FF, 0x101 };
1128 
1129 	state = blank ? APM_STATE_STANDBY : APM_STATE_READY;
1130 
1131 	for (i = 0; i < ARRAY_SIZE(dev); i++) {
1132 		error = set_power_state(dev[i], state);
1133 
1134 		if ((error == APM_SUCCESS) || (error == APM_NO_ERROR))
1135 			return 1;
1136 
1137 		if (error == APM_NOT_ENGAGED)
1138 			break;
1139 	}
1140 
1141 	if (error == APM_NOT_ENGAGED) {
1142 		static int tried;
1143 		int eng_error;
1144 		if (tried++ == 0) {
1145 			eng_error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1146 			if (eng_error) {
1147 				apm_error("set display", error);
1148 				apm_error("engage interface", eng_error);
1149 				return 0;
1150 			} else
1151 				return apm_console_blank(blank);
1152 		}
1153 	}
1154 	apm_error("set display", error);
1155 	return 0;
1156 }
1157 #endif
1158 
1159 static int queue_empty(struct apm_user *as)
1160 {
1161 	return as->event_head == as->event_tail;
1162 }
1163 
1164 static apm_event_t get_queued_event(struct apm_user *as)
1165 {
1166 	if (++as->event_tail >= APM_MAX_EVENTS)
1167 		as->event_tail = 0;
1168 	return as->events[as->event_tail];
1169 }
1170 
1171 static void queue_event(apm_event_t event, struct apm_user *sender)
1172 {
1173 	struct apm_user *as;
1174 
1175 	spin_lock(&user_list_lock);
1176 	if (user_list == NULL)
1177 		goto out;
1178 	for (as = user_list; as != NULL; as = as->next) {
1179 		if ((as == sender) || (!as->reader))
1180 			continue;
1181 		if (++as->event_head >= APM_MAX_EVENTS)
1182 			as->event_head = 0;
1183 
1184 		if (as->event_head == as->event_tail) {
1185 			static int notified;
1186 
1187 			if (notified++ == 0)
1188 			    printk(KERN_ERR "apm: an event queue overflowed\n");
1189 			if (++as->event_tail >= APM_MAX_EVENTS)
1190 				as->event_tail = 0;
1191 		}
1192 		as->events[as->event_head] = event;
1193 		if (!as->suser || !as->writer)
1194 			continue;
1195 		switch (event) {
1196 		case APM_SYS_SUSPEND:
1197 		case APM_USER_SUSPEND:
1198 			as->suspends_pending++;
1199 			suspends_pending++;
1200 			break;
1201 
1202 		case APM_SYS_STANDBY:
1203 		case APM_USER_STANDBY:
1204 			as->standbys_pending++;
1205 			standbys_pending++;
1206 			break;
1207 		}
1208 	}
1209 	wake_up_interruptible(&apm_waitqueue);
1210 out:
1211 	spin_unlock(&user_list_lock);
1212 }
1213 
1214 static void reinit_timer(void)
1215 {
1216 #ifdef INIT_TIMER_AFTER_SUSPEND
1217 	unsigned long flags;
1218 
1219 	spin_lock_irqsave(&i8253_lock, flags);
1220 	/* set the clock to HZ */
1221 	outb_pit(0x34, PIT_MODE);		/* binary, mode 2, LSB/MSB, ch 0 */
1222 	udelay(10);
1223 	outb_pit(LATCH & 0xff, PIT_CH0);	/* LSB */
1224 	udelay(10);
1225 	outb_pit(LATCH >> 8, PIT_CH0);	/* MSB */
1226 	udelay(10);
1227 	spin_unlock_irqrestore(&i8253_lock, flags);
1228 #endif
1229 }
1230 
1231 static int suspend(int vetoable)
1232 {
1233 	int err;
1234 	struct apm_user	*as;
1235 
1236 	device_suspend(PMSG_SUSPEND);
1237 
1238 	device_power_down(PMSG_SUSPEND);
1239 
1240 	local_irq_disable();
1241 	sysdev_suspend(PMSG_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 	sysdev_resume();
1260 	local_irq_enable();
1261 
1262 	device_power_up(PMSG_RESUME);
1263 
1264 	device_resume(PMSG_RESUME);
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 	device_power_down(PMSG_SUSPEND);
1281 
1282 	local_irq_disable();
1283 	sysdev_suspend(PMSG_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 	sysdev_resume();
1292 	local_irq_enable();
1293 
1294 	device_power_up(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 				device_resume(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 		printk(KERN_ERR "apm: %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 		lock_kernel();
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 		unlock_kernel();
1536 		break;
1537 	case APM_IOC_SUSPEND:
1538 		lock_kernel();
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 		} else {
1548 			as->suspend_wait = 1;
1549 			wait_event_interruptible(apm_suspend_waitqueue,
1550 					as->suspend_wait == 0);
1551 			ret = as->suspend_result;
1552 		}
1553 		unlock_kernel();
1554 		return ret;
1555 	default:
1556 		return -ENOTTY;
1557 	}
1558 	return 0;
1559 }
1560 
1561 static int do_release(struct inode *inode, struct file *filp)
1562 {
1563 	struct apm_user *as;
1564 
1565 	as = filp->private_data;
1566 	if (check_apm_user(as, "release"))
1567 		return 0;
1568 	filp->private_data = NULL;
1569 	if (as->standbys_pending > 0) {
1570 		standbys_pending -= as->standbys_pending;
1571 		if (standbys_pending <= 0)
1572 			standby();
1573 	}
1574 	if (as->suspends_pending > 0) {
1575 		suspends_pending -= as->suspends_pending;
1576 		if (suspends_pending <= 0)
1577 			(void) suspend(1);
1578 	}
1579 	spin_lock(&user_list_lock);
1580 	if (user_list == as)
1581 		user_list = as->next;
1582 	else {
1583 		struct apm_user *as1;
1584 
1585 		for (as1 = user_list;
1586 		     (as1 != NULL) && (as1->next != as);
1587 		     as1 = as1->next)
1588 			;
1589 		if (as1 == NULL)
1590 			printk(KERN_ERR "apm: filp not in user list\n");
1591 		else
1592 			as1->next = as->next;
1593 	}
1594 	spin_unlock(&user_list_lock);
1595 	kfree(as);
1596 	return 0;
1597 }
1598 
1599 static int do_open(struct inode *inode, struct file *filp)
1600 {
1601 	struct apm_user *as;
1602 
1603 	lock_kernel();
1604 	as = kmalloc(sizeof(*as), GFP_KERNEL);
1605 	if (as == NULL) {
1606 		printk(KERN_ERR "apm: cannot allocate struct of size %d bytes\n",
1607 		       sizeof(*as));
1608 		       unlock_kernel();
1609 		return -ENOMEM;
1610 	}
1611 	as->magic = APM_BIOS_MAGIC;
1612 	as->event_tail = as->event_head = 0;
1613 	as->suspends_pending = as->standbys_pending = 0;
1614 	as->suspends_read = as->standbys_read = 0;
1615 	/*
1616 	 * XXX - this is a tiny bit broken, when we consider BSD
1617 	 * process accounting. If the device is opened by root, we
1618 	 * instantly flag that we used superuser privs. Who knows,
1619 	 * we might close the device immediately without doing a
1620 	 * privileged operation -- cevans
1621 	 */
1622 	as->suser = capable(CAP_SYS_ADMIN);
1623 	as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
1624 	as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
1625 	spin_lock(&user_list_lock);
1626 	as->next = user_list;
1627 	user_list = as;
1628 	spin_unlock(&user_list_lock);
1629 	filp->private_data = as;
1630 	unlock_kernel();
1631 	return 0;
1632 }
1633 
1634 static int proc_apm_show(struct seq_file *m, void *v)
1635 {
1636 	unsigned short	bx;
1637 	unsigned short	cx;
1638 	unsigned short	dx;
1639 	int		error;
1640 	unsigned short  ac_line_status = 0xff;
1641 	unsigned short  battery_status = 0xff;
1642 	unsigned short  battery_flag   = 0xff;
1643 	int		percentage     = -1;
1644 	int             time_units     = -1;
1645 	char            *units         = "?";
1646 
1647 	if ((num_online_cpus() == 1) &&
1648 	    !(error = apm_get_power_status(&bx, &cx, &dx))) {
1649 		ac_line_status = (bx >> 8) & 0xff;
1650 		battery_status = bx & 0xff;
1651 		if ((cx & 0xff) != 0xff)
1652 			percentage = cx & 0xff;
1653 
1654 		if (apm_info.connection_version > 0x100) {
1655 			battery_flag = (cx >> 8) & 0xff;
1656 			if (dx != 0xffff) {
1657 				units = (dx & 0x8000) ? "min" : "sec";
1658 				time_units = dx & 0x7fff;
1659 			}
1660 		}
1661 	}
1662 	/* Arguments, with symbols from linux/apm_bios.h.  Information is
1663 	   from the Get Power Status (0x0a) call unless otherwise noted.
1664 
1665 	   0) Linux driver version (this will change if format changes)
1666 	   1) APM BIOS Version.  Usually 1.0, 1.1 or 1.2.
1667 	   2) APM flags from APM Installation Check (0x00):
1668 	      bit 0: APM_16_BIT_SUPPORT
1669 	      bit 1: APM_32_BIT_SUPPORT
1670 	      bit 2: APM_IDLE_SLOWS_CLOCK
1671 	      bit 3: APM_BIOS_DISABLED
1672 	      bit 4: APM_BIOS_DISENGAGED
1673 	   3) AC line status
1674 	      0x00: Off-line
1675 	      0x01: On-line
1676 	      0x02: On backup power (BIOS >= 1.1 only)
1677 	      0xff: Unknown
1678 	   4) Battery status
1679 	      0x00: High
1680 	      0x01: Low
1681 	      0x02: Critical
1682 	      0x03: Charging
1683 	      0x04: Selected battery not present (BIOS >= 1.2 only)
1684 	      0xff: Unknown
1685 	   5) Battery flag
1686 	      bit 0: High
1687 	      bit 1: Low
1688 	      bit 2: Critical
1689 	      bit 3: Charging
1690 	      bit 7: No system battery
1691 	      0xff: Unknown
1692 	   6) Remaining battery life (percentage of charge):
1693 	      0-100: valid
1694 	      -1: Unknown
1695 	   7) Remaining battery life (time units):
1696 	      Number of remaining minutes or seconds
1697 	      -1: Unknown
1698 	   8) min = minutes; sec = seconds */
1699 
1700 	seq_printf(m, "%s %d.%d 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
1701 		   driver_version,
1702 		   (apm_info.bios.version >> 8) & 0xff,
1703 		   apm_info.bios.version & 0xff,
1704 		   apm_info.bios.flags,
1705 		   ac_line_status,
1706 		   battery_status,
1707 		   battery_flag,
1708 		   percentage,
1709 		   time_units,
1710 		   units);
1711 	return 0;
1712 }
1713 
1714 static int proc_apm_open(struct inode *inode, struct file *file)
1715 {
1716 	return single_open(file, proc_apm_show, NULL);
1717 }
1718 
1719 static const struct file_operations apm_file_ops = {
1720 	.owner		= THIS_MODULE,
1721 	.open		= proc_apm_open,
1722 	.read		= seq_read,
1723 	.llseek		= seq_lseek,
1724 	.release	= single_release,
1725 };
1726 
1727 static int apm(void *unused)
1728 {
1729 	unsigned short	bx;
1730 	unsigned short	cx;
1731 	unsigned short	dx;
1732 	int		error;
1733 	char 		*power_stat;
1734 	char 		*bat_stat;
1735 
1736 	/* 2002/08/01 - WT
1737 	 * This is to avoid random crashes at boot time during initialization
1738 	 * on SMP systems in case of "apm=power-off" mode. Seen on ASUS A7M266D.
1739 	 * Some bioses don't like being called from CPU != 0.
1740 	 * Method suggested by Ingo Molnar.
1741 	 */
1742 	set_cpus_allowed_ptr(current, cpumask_of(0));
1743 	BUG_ON(smp_processor_id() != 0);
1744 
1745 	if (apm_info.connection_version == 0) {
1746 		apm_info.connection_version = apm_info.bios.version;
1747 		if (apm_info.connection_version > 0x100) {
1748 			/*
1749 			 * We only support BIOSs up to version 1.2
1750 			 */
1751 			if (apm_info.connection_version > 0x0102)
1752 				apm_info.connection_version = 0x0102;
1753 			error = apm_driver_version(&apm_info.connection_version);
1754 			if (error != APM_SUCCESS) {
1755 				apm_error("driver version", error);
1756 				/* Fall back to an APM 1.0 connection. */
1757 				apm_info.connection_version = 0x100;
1758 			}
1759 		}
1760 	}
1761 
1762 	if (debug)
1763 		printk(KERN_INFO "apm: Connection version %d.%d\n",
1764 			(apm_info.connection_version >> 8) & 0xff,
1765 			apm_info.connection_version & 0xff);
1766 
1767 #ifdef CONFIG_APM_DO_ENABLE
1768 	if (apm_info.bios.flags & APM_BIOS_DISABLED) {
1769 		/*
1770 		 * This call causes my NEC UltraLite Versa 33/C to hang if it
1771 		 * is booted with PM disabled but not in the docking station.
1772 		 * Unfortunate ...
1773 		 */
1774 		error = apm_enable_power_management(1);
1775 		if (error) {
1776 			apm_error("enable power management", error);
1777 			return -1;
1778 		}
1779 	}
1780 #endif
1781 
1782 	if ((apm_info.bios.flags & APM_BIOS_DISENGAGED)
1783 	    && (apm_info.connection_version > 0x0100)) {
1784 		error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1785 		if (error) {
1786 			apm_error("engage power management", error);
1787 			return -1;
1788 		}
1789 	}
1790 
1791 	if (debug && (num_online_cpus() == 1 || smp)) {
1792 		error = apm_get_power_status(&bx, &cx, &dx);
1793 		if (error)
1794 			printk(KERN_INFO "apm: power status not available\n");
1795 		else {
1796 			switch ((bx >> 8) & 0xff) {
1797 			case 0:
1798 				power_stat = "off line";
1799 				break;
1800 			case 1:
1801 				power_stat = "on line";
1802 				break;
1803 			case 2:
1804 				power_stat = "on backup power";
1805 				break;
1806 			default:
1807 				power_stat = "unknown";
1808 				break;
1809 			}
1810 			switch (bx & 0xff) {
1811 			case 0:
1812 				bat_stat = "high";
1813 				break;
1814 			case 1:
1815 				bat_stat = "low";
1816 				break;
1817 			case 2:
1818 				bat_stat = "critical";
1819 				break;
1820 			case 3:
1821 				bat_stat = "charging";
1822 				break;
1823 			default:
1824 				bat_stat = "unknown";
1825 				break;
1826 			}
1827 			printk(KERN_INFO
1828 			       "apm: AC %s, battery status %s, battery life ",
1829 			       power_stat, bat_stat);
1830 			if ((cx & 0xff) == 0xff)
1831 				printk("unknown\n");
1832 			else
1833 				printk("%d%%\n", cx & 0xff);
1834 			if (apm_info.connection_version > 0x100) {
1835 				printk(KERN_INFO
1836 				       "apm: battery flag 0x%02x, battery life ",
1837 				       (cx >> 8) & 0xff);
1838 				if (dx == 0xffff)
1839 					printk("unknown\n");
1840 				else
1841 					printk("%d %s\n", dx & 0x7fff,
1842 					       (dx & 0x8000) ?
1843 					       "minutes" : "seconds");
1844 			}
1845 		}
1846 	}
1847 
1848 	/* Install our power off handler.. */
1849 	if (power_off)
1850 		pm_power_off = apm_power_off;
1851 
1852 	if (num_online_cpus() == 1 || smp) {
1853 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1854 		console_blank_hook = apm_console_blank;
1855 #endif
1856 		apm_mainloop();
1857 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1858 		console_blank_hook = NULL;
1859 #endif
1860 	}
1861 
1862 	return 0;
1863 }
1864 
1865 #ifndef MODULE
1866 static int __init apm_setup(char *str)
1867 {
1868 	int invert;
1869 
1870 	while ((str != NULL) && (*str != '\0')) {
1871 		if (strncmp(str, "off", 3) == 0)
1872 			apm_disabled = 1;
1873 		if (strncmp(str, "on", 2) == 0)
1874 			apm_disabled = 0;
1875 		if ((strncmp(str, "bounce-interval=", 16) == 0) ||
1876 		    (strncmp(str, "bounce_interval=", 16) == 0))
1877 			bounce_interval = simple_strtol(str + 16, NULL, 0);
1878 		if ((strncmp(str, "idle-threshold=", 15) == 0) ||
1879 		    (strncmp(str, "idle_threshold=", 15) == 0))
1880 			idle_threshold = simple_strtol(str + 15, NULL, 0);
1881 		if ((strncmp(str, "idle-period=", 12) == 0) ||
1882 		    (strncmp(str, "idle_period=", 12) == 0))
1883 			idle_period = simple_strtol(str + 12, NULL, 0);
1884 		invert = (strncmp(str, "no-", 3) == 0) ||
1885 			(strncmp(str, "no_", 3) == 0);
1886 		if (invert)
1887 			str += 3;
1888 		if (strncmp(str, "debug", 5) == 0)
1889 			debug = !invert;
1890 		if ((strncmp(str, "power-off", 9) == 0) ||
1891 		    (strncmp(str, "power_off", 9) == 0))
1892 			power_off = !invert;
1893 		if (strncmp(str, "smp", 3) == 0) {
1894 			smp = !invert;
1895 			idle_threshold = 100;
1896 		}
1897 		if ((strncmp(str, "allow-ints", 10) == 0) ||
1898 		    (strncmp(str, "allow_ints", 10) == 0))
1899 			apm_info.allow_ints = !invert;
1900 		if ((strncmp(str, "broken-psr", 10) == 0) ||
1901 		    (strncmp(str, "broken_psr", 10) == 0))
1902 			apm_info.get_power_status_broken = !invert;
1903 		if ((strncmp(str, "realmode-power-off", 18) == 0) ||
1904 		    (strncmp(str, "realmode_power_off", 18) == 0))
1905 			apm_info.realmode_power_off = !invert;
1906 		str = strchr(str, ',');
1907 		if (str != NULL)
1908 			str += strspn(str, ", \t");
1909 	}
1910 	return 1;
1911 }
1912 
1913 __setup("apm=", apm_setup);
1914 #endif
1915 
1916 static const struct file_operations apm_bios_fops = {
1917 	.owner		= THIS_MODULE,
1918 	.read		= do_read,
1919 	.poll		= do_poll,
1920 	.unlocked_ioctl	= do_ioctl,
1921 	.open		= do_open,
1922 	.release	= do_release,
1923 };
1924 
1925 static struct miscdevice apm_device = {
1926 	APM_MINOR_DEV,
1927 	"apm_bios",
1928 	&apm_bios_fops
1929 };
1930 
1931 
1932 /* Simple "print if true" callback */
1933 static int __init print_if_true(const struct dmi_system_id *d)
1934 {
1935 	printk("%s\n", d->ident);
1936 	return 0;
1937 }
1938 
1939 /*
1940  * Some Bioses enable the PS/2 mouse (touchpad) at resume, even if it was
1941  * disabled before the suspend. Linux used to get terribly confused by that.
1942  */
1943 static int __init broken_ps2_resume(const struct dmi_system_id *d)
1944 {
1945 	printk(KERN_INFO "%s machine detected. Mousepad Resume Bug "
1946 	       "workaround hopefully not needed.\n", d->ident);
1947 	return 0;
1948 }
1949 
1950 /* Some bioses have a broken protected mode poweroff and need to use realmode */
1951 static int __init set_realmode_power_off(const struct dmi_system_id *d)
1952 {
1953 	if (apm_info.realmode_power_off == 0) {
1954 		apm_info.realmode_power_off = 1;
1955 		printk(KERN_INFO "%s bios detected. "
1956 		       "Using realmode poweroff only.\n", d->ident);
1957 	}
1958 	return 0;
1959 }
1960 
1961 /* Some laptops require interrupts to be enabled during APM calls */
1962 static int __init set_apm_ints(const struct dmi_system_id *d)
1963 {
1964 	if (apm_info.allow_ints == 0) {
1965 		apm_info.allow_ints = 1;
1966 		printk(KERN_INFO "%s machine detected. "
1967 		       "Enabling interrupts during APM calls.\n", d->ident);
1968 	}
1969 	return 0;
1970 }
1971 
1972 /* Some APM bioses corrupt memory or just plain do not work */
1973 static int __init apm_is_horked(const struct dmi_system_id *d)
1974 {
1975 	if (apm_info.disabled == 0) {
1976 		apm_info.disabled = 1;
1977 		printk(KERN_INFO "%s machine detected. "
1978 		       "Disabling APM.\n", d->ident);
1979 	}
1980 	return 0;
1981 }
1982 
1983 static int __init apm_is_horked_d850md(const struct dmi_system_id *d)
1984 {
1985 	if (apm_info.disabled == 0) {
1986 		apm_info.disabled = 1;
1987 		printk(KERN_INFO "%s machine detected. "
1988 		       "Disabling APM.\n", d->ident);
1989 		printk(KERN_INFO "This bug is fixed in bios P15 which is available for \n");
1990 		printk(KERN_INFO "download from support.intel.com \n");
1991 	}
1992 	return 0;
1993 }
1994 
1995 /* Some APM bioses hang on APM idle calls */
1996 static int __init apm_likes_to_melt(const struct dmi_system_id *d)
1997 {
1998 	if (apm_info.forbid_idle == 0) {
1999 		apm_info.forbid_idle = 1;
2000 		printk(KERN_INFO "%s machine detected. "
2001 		       "Disabling APM idle calls.\n", d->ident);
2002 	}
2003 	return 0;
2004 }
2005 
2006 /*
2007  *  Check for clue free BIOS implementations who use
2008  *  the following QA technique
2009  *
2010  *      [ Write BIOS Code ]<------
2011  *               |                ^
2012  *      < Does it Compile >----N--
2013  *               |Y               ^
2014  *	< Does it Boot Win98 >-N--
2015  *               |Y
2016  *           [Ship It]
2017  *
2018  *	Phoenix A04  08/24/2000 is known bad (Dell Inspiron 5000e)
2019  *	Phoenix A07  09/29/2000 is known good (Dell Inspiron 5000)
2020  */
2021 static int __init broken_apm_power(const struct dmi_system_id *d)
2022 {
2023 	apm_info.get_power_status_broken = 1;
2024 	printk(KERN_WARNING "BIOS strings suggest APM bugs, "
2025 	       "disabling power status reporting.\n");
2026 	return 0;
2027 }
2028 
2029 /*
2030  * This bios swaps the APM minute reporting bytes over (Many sony laptops
2031  * have this problem).
2032  */
2033 static int __init swab_apm_power_in_minutes(const struct dmi_system_id *d)
2034 {
2035 	apm_info.get_power_status_swabinminutes = 1;
2036 	printk(KERN_WARNING "BIOS strings suggest APM reports battery life "
2037 	       "in minutes and wrong byte order.\n");
2038 	return 0;
2039 }
2040 
2041 static struct dmi_system_id __initdata apm_dmi_table[] = {
2042 	{
2043 		print_if_true,
2044 		KERN_WARNING "IBM T23 - BIOS 1.03b+ and controller firmware 1.02+ may be needed for Linux APM.",
2045 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
2046 			DMI_MATCH(DMI_BIOS_VERSION, "1AET38WW (1.01b)"), },
2047 	},
2048 	{	/* Handle problems with APM on the C600 */
2049 		broken_ps2_resume, "Dell Latitude C600",
2050 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
2051 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C600"), },
2052 	},
2053 	{	/* Allow interrupts during suspend on Dell Latitude laptops*/
2054 		set_apm_ints, "Dell Latitude",
2055 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2056 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C510"), }
2057 	},
2058 	{	/* APM crashes */
2059 		apm_is_horked, "Dell Inspiron 2500",
2060 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2061 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2062 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2063 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2064 	},
2065 	{	/* Allow interrupts during suspend on Dell Inspiron laptops*/
2066 		set_apm_ints, "Dell Inspiron", {
2067 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2068 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 4000"), },
2069 	},
2070 	{	/* Handle problems with APM on Inspiron 5000e */
2071 		broken_apm_power, "Dell Inspiron 5000e",
2072 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2073 			DMI_MATCH(DMI_BIOS_VERSION, "A04"),
2074 			DMI_MATCH(DMI_BIOS_DATE, "08/24/2000"), },
2075 	},
2076 	{	/* Handle problems with APM on Inspiron 2500 */
2077 		broken_apm_power, "Dell Inspiron 2500",
2078 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2079 			DMI_MATCH(DMI_BIOS_VERSION, "A12"),
2080 			DMI_MATCH(DMI_BIOS_DATE, "02/04/2002"), },
2081 	},
2082 	{	/* APM crashes */
2083 		apm_is_horked, "Dell Dimension 4100",
2084 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2085 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"),
2086 			DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2087 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2088 	},
2089 	{	/* Allow interrupts during suspend on Compaq Laptops*/
2090 		set_apm_ints, "Compaq 12XL125",
2091 		{	DMI_MATCH(DMI_SYS_VENDOR, "Compaq"),
2092 			DMI_MATCH(DMI_PRODUCT_NAME, "Compaq PC"),
2093 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2094 			DMI_MATCH(DMI_BIOS_VERSION, "4.06"), },
2095 	},
2096 	{	/* Allow interrupts during APM or the clock goes slow */
2097 		set_apm_ints, "ASUSTeK",
2098 		{	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
2099 			DMI_MATCH(DMI_PRODUCT_NAME, "L8400K series Notebook PC"), },
2100 	},
2101 	{	/* APM blows on shutdown */
2102 		apm_is_horked, "ABIT KX7-333[R]",
2103 		{	DMI_MATCH(DMI_BOARD_VENDOR, "ABIT"),
2104 			DMI_MATCH(DMI_BOARD_NAME, "VT8367-8233A (KX7-333[R])"), },
2105 	},
2106 	{	/* APM crashes */
2107 		apm_is_horked, "Trigem Delhi3",
2108 		{	DMI_MATCH(DMI_SYS_VENDOR, "TriGem Computer, Inc"),
2109 			DMI_MATCH(DMI_PRODUCT_NAME, "Delhi3"), },
2110 	},
2111 	{	/* APM crashes */
2112 		apm_is_horked, "Fujitsu-Siemens",
2113 		{	DMI_MATCH(DMI_BIOS_VENDOR, "hoenix/FUJITSU SIEMENS"),
2114 			DMI_MATCH(DMI_BIOS_VERSION, "Version1.01"), },
2115 	},
2116 	{	/* APM crashes */
2117 		apm_is_horked_d850md, "Intel D850MD",
2118 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2119 			DMI_MATCH(DMI_BIOS_VERSION, "MV85010A.86A.0016.P07.0201251536"), },
2120 	},
2121 	{	/* APM crashes */
2122 		apm_is_horked, "Intel D810EMO",
2123 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2124 			DMI_MATCH(DMI_BIOS_VERSION, "MO81010A.86A.0008.P04.0004170800"), },
2125 	},
2126 	{	/* APM crashes */
2127 		apm_is_horked, "Dell XPS-Z",
2128 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2129 			DMI_MATCH(DMI_BIOS_VERSION, "A11"),
2130 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"), },
2131 	},
2132 	{	/* APM crashes */
2133 		apm_is_horked, "Sharp PC-PJ/AX",
2134 		{	DMI_MATCH(DMI_SYS_VENDOR, "SHARP"),
2135 			DMI_MATCH(DMI_PRODUCT_NAME, "PC-PJ/AX"),
2136 			DMI_MATCH(DMI_BIOS_VENDOR, "SystemSoft"),
2137 			DMI_MATCH(DMI_BIOS_VERSION, "Version R2.08"), },
2138 	},
2139 	{	/* APM crashes */
2140 		apm_is_horked, "Dell Inspiron 2500",
2141 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2142 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2143 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2144 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2145 	},
2146 	{	/* APM idle hangs */
2147 		apm_likes_to_melt, "Jabil AMD",
2148 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2149 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP06"), },
2150 	},
2151 	{	/* APM idle hangs */
2152 		apm_likes_to_melt, "AMI Bios",
2153 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2154 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP05"), },
2155 	},
2156 	{	/* Handle problems with APM on Sony Vaio PCG-N505X(DE) */
2157 		swab_apm_power_in_minutes, "Sony VAIO",
2158 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2159 			DMI_MATCH(DMI_BIOS_VERSION, "R0206H"),
2160 			DMI_MATCH(DMI_BIOS_DATE, "08/23/99"), },
2161 	},
2162 	{	/* Handle problems with APM on Sony Vaio PCG-N505VX */
2163 		swab_apm_power_in_minutes, "Sony VAIO",
2164 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2165 			DMI_MATCH(DMI_BIOS_VERSION, "W2K06H0"),
2166 			DMI_MATCH(DMI_BIOS_DATE, "02/03/00"), },
2167 	},
2168 	{	/* Handle problems with APM on Sony Vaio PCG-XG29 */
2169 		swab_apm_power_in_minutes, "Sony VAIO",
2170 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2171 			DMI_MATCH(DMI_BIOS_VERSION, "R0117A0"),
2172 			DMI_MATCH(DMI_BIOS_DATE, "04/25/00"), },
2173 	},
2174 	{	/* Handle problems with APM on Sony Vaio PCG-Z600NE */
2175 		swab_apm_power_in_minutes, "Sony VAIO",
2176 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2177 			DMI_MATCH(DMI_BIOS_VERSION, "R0121Z1"),
2178 			DMI_MATCH(DMI_BIOS_DATE, "05/11/00"), },
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, "WME01Z1"),
2184 			DMI_MATCH(DMI_BIOS_DATE, "08/11/00"), },
2185 	},
2186 	{	/* Handle problems with APM on Sony Vaio PCG-Z600LEK(DE) */
2187 		swab_apm_power_in_minutes, "Sony VAIO",
2188 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2189 			DMI_MATCH(DMI_BIOS_VERSION, "R0206Z3"),
2190 			DMI_MATCH(DMI_BIOS_DATE, "12/25/00"), },
2191 	},
2192 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS */
2193 		swab_apm_power_in_minutes, "Sony VAIO",
2194 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2195 			DMI_MATCH(DMI_BIOS_VERSION, "R0203D0"),
2196 			DMI_MATCH(DMI_BIOS_DATE, "05/12/00"), },
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, "R0203Z3"),
2202 			DMI_MATCH(DMI_BIOS_DATE, "08/25/00"), },
2203 	},
2204 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS (with updated BIOS) */
2205 		swab_apm_power_in_minutes, "Sony VAIO",
2206 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2207 			DMI_MATCH(DMI_BIOS_VERSION, "R0209Z3"),
2208 			DMI_MATCH(DMI_BIOS_DATE, "05/12/01"), },
2209 	},
2210 	{	/* Handle problems with APM on Sony Vaio PCG-F104K */
2211 		swab_apm_power_in_minutes, "Sony VAIO",
2212 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2213 			DMI_MATCH(DMI_BIOS_VERSION, "R0204K2"),
2214 			DMI_MATCH(DMI_BIOS_DATE, "08/28/00"), },
2215 	},
2216 
2217 	{	/* Handle problems with APM on Sony Vaio PCG-C1VN/C1VE */
2218 		swab_apm_power_in_minutes, "Sony VAIO",
2219 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2220 			DMI_MATCH(DMI_BIOS_VERSION, "R0208P1"),
2221 			DMI_MATCH(DMI_BIOS_DATE, "11/09/00"), },
2222 	},
2223 	{	/* Handle problems with APM on Sony Vaio PCG-C1VE */
2224 		swab_apm_power_in_minutes, "Sony VAIO",
2225 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2226 			DMI_MATCH(DMI_BIOS_VERSION, "R0204P1"),
2227 			DMI_MATCH(DMI_BIOS_DATE, "09/12/00"), },
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, "WXPO1Z3"),
2233 			DMI_MATCH(DMI_BIOS_DATE, "10/26/01"), },
2234 	},
2235 	{	/* broken PM poweroff bios */
2236 		set_realmode_power_off, "Award Software v4.60 PGMA",
2237 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Award Software International, Inc."),
2238 			DMI_MATCH(DMI_BIOS_VERSION, "4.60 PGMA"),
2239 			DMI_MATCH(DMI_BIOS_DATE, "134526184"), },
2240 	},
2241 
2242 	/* Generic per vendor APM settings  */
2243 
2244 	{	/* Allow interrupts during suspend on IBM laptops */
2245 		set_apm_ints, "IBM",
2246 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"), },
2247 	},
2248 
2249 	{ }
2250 };
2251 
2252 /*
2253  * Just start the APM thread. We do NOT want to do APM BIOS
2254  * calls from anything but the APM thread, if for no other reason
2255  * than the fact that we don't trust the APM BIOS. This way,
2256  * most common APM BIOS problems that lead to protection errors
2257  * etc will have at least some level of being contained...
2258  *
2259  * In short, if something bad happens, at least we have a choice
2260  * of just killing the apm thread..
2261  */
2262 static int __init apm_init(void)
2263 {
2264 	struct desc_struct *gdt;
2265 	int err;
2266 
2267 	dmi_check_system(apm_dmi_table);
2268 
2269 	if (apm_info.bios.version == 0 || paravirt_enabled() || machine_is_olpc()) {
2270 		printk(KERN_INFO "apm: BIOS not found.\n");
2271 		return -ENODEV;
2272 	}
2273 	printk(KERN_INFO
2274 	       "apm: BIOS version %d.%d Flags 0x%02x (Driver version %s)\n",
2275 	       ((apm_info.bios.version >> 8) & 0xff),
2276 	       (apm_info.bios.version & 0xff),
2277 	       apm_info.bios.flags,
2278 	       driver_version);
2279 	if ((apm_info.bios.flags & APM_32_BIT_SUPPORT) == 0) {
2280 		printk(KERN_INFO "apm: no 32 bit BIOS support\n");
2281 		return -ENODEV;
2282 	}
2283 
2284 	if (allow_ints)
2285 		apm_info.allow_ints = 1;
2286 	if (broken_psr)
2287 		apm_info.get_power_status_broken = 1;
2288 	if (realmode_power_off)
2289 		apm_info.realmode_power_off = 1;
2290 	/* User can override, but default is to trust DMI */
2291 	if (apm_disabled != -1)
2292 		apm_info.disabled = apm_disabled;
2293 
2294 	/*
2295 	 * Fix for the Compaq Contura 3/25c which reports BIOS version 0.1
2296 	 * but is reportedly a 1.0 BIOS.
2297 	 */
2298 	if (apm_info.bios.version == 0x001)
2299 		apm_info.bios.version = 0x100;
2300 
2301 	/* BIOS < 1.2 doesn't set cseg_16_len */
2302 	if (apm_info.bios.version < 0x102)
2303 		apm_info.bios.cseg_16_len = 0; /* 64k */
2304 
2305 	if (debug) {
2306 		printk(KERN_INFO "apm: entry %x:%x cseg16 %x dseg %x",
2307 			apm_info.bios.cseg, apm_info.bios.offset,
2308 			apm_info.bios.cseg_16, apm_info.bios.dseg);
2309 		if (apm_info.bios.version > 0x100)
2310 			printk(" cseg len %x, dseg len %x",
2311 				apm_info.bios.cseg_len,
2312 				apm_info.bios.dseg_len);
2313 		if (apm_info.bios.version > 0x101)
2314 			printk(" cseg16 len %x", apm_info.bios.cseg_16_len);
2315 		printk("\n");
2316 	}
2317 
2318 	if (apm_info.disabled) {
2319 		printk(KERN_NOTICE "apm: disabled on user request.\n");
2320 		return -ENODEV;
2321 	}
2322 	if ((num_online_cpus() > 1) && !power_off && !smp) {
2323 		printk(KERN_NOTICE "apm: disabled - APM is not SMP safe.\n");
2324 		apm_info.disabled = 1;
2325 		return -ENODEV;
2326 	}
2327 	if (pm_flags & PM_ACPI) {
2328 		printk(KERN_NOTICE "apm: overridden by ACPI.\n");
2329 		apm_info.disabled = 1;
2330 		return -ENODEV;
2331 	}
2332 	pm_flags |= PM_APM;
2333 
2334 	/*
2335 	 * Set up a segment that references the real mode segment 0x40
2336 	 * that extends up to the end of page zero (that we have reserved).
2337 	 * This is for buggy BIOS's that refer to (real mode) segment 0x40
2338 	 * even though they are called in protected mode.
2339 	 */
2340 	set_base(bad_bios_desc, __va((unsigned long)0x40 << 4));
2341 	_set_limit((char *)&bad_bios_desc, 4095 - (0x40 << 4));
2342 
2343 	/*
2344 	 * Set up the long jump entry point to the APM BIOS, which is called
2345 	 * from inline assembly.
2346 	 */
2347 	apm_bios_entry.offset = apm_info.bios.offset;
2348 	apm_bios_entry.segment = APM_CS;
2349 
2350 	/*
2351 	 * The APM 1.1 BIOS is supposed to provide limit information that it
2352 	 * recognizes.  Many machines do this correctly, but many others do
2353 	 * not restrict themselves to their claimed limit.  When this happens,
2354 	 * they will cause a segmentation violation in the kernel at boot time.
2355 	 * Most BIOS's, however, will respect a 64k limit, so we use that.
2356 	 *
2357 	 * Note we only set APM segments on CPU zero, since we pin the APM
2358 	 * code to that CPU.
2359 	 */
2360 	gdt = get_cpu_gdt_table(0);
2361 	set_base(gdt[APM_CS >> 3],
2362 		 __va((unsigned long)apm_info.bios.cseg << 4));
2363 	set_base(gdt[APM_CS_16 >> 3],
2364 		 __va((unsigned long)apm_info.bios.cseg_16 << 4));
2365 	set_base(gdt[APM_DS >> 3],
2366 		 __va((unsigned long)apm_info.bios.dseg << 4));
2367 
2368 	proc_create("apm", 0, NULL, &apm_file_ops);
2369 
2370 	kapmd_task = kthread_create(apm, NULL, "kapmd");
2371 	if (IS_ERR(kapmd_task)) {
2372 		printk(KERN_ERR "apm: disabled - Unable to start kernel "
2373 				"thread.\n");
2374 		err = PTR_ERR(kapmd_task);
2375 		kapmd_task = NULL;
2376 		remove_proc_entry("apm", NULL);
2377 		return err;
2378 	}
2379 	wake_up_process(kapmd_task);
2380 
2381 	if (num_online_cpus() > 1 && !smp) {
2382 		printk(KERN_NOTICE
2383 		       "apm: disabled - APM is not SMP safe (power off active).\n");
2384 		return 0;
2385 	}
2386 
2387 	/*
2388 	 * Note we don't actually care if the misc_device cannot be registered.
2389 	 * this driver can do its job without it, even if userspace can't
2390 	 * control it.  just log the error
2391 	 */
2392 	if (misc_register(&apm_device))
2393 		printk(KERN_WARNING "apm: Could not register misc device.\n");
2394 
2395 	if (HZ != 100)
2396 		idle_period = (idle_period * HZ) / 100;
2397 	if (idle_threshold < 100) {
2398 		original_pm_idle = pm_idle;
2399 		pm_idle  = apm_cpu_idle;
2400 		set_pm_idle = 1;
2401 	}
2402 
2403 	return 0;
2404 }
2405 
2406 static void __exit apm_exit(void)
2407 {
2408 	int error;
2409 
2410 	if (set_pm_idle) {
2411 		pm_idle = original_pm_idle;
2412 		/*
2413 		 * We are about to unload the current idle thread pm callback
2414 		 * (pm_idle), Wait for all processors to update cached/local
2415 		 * copies of pm_idle before proceeding.
2416 		 */
2417 		cpu_idle_wait();
2418 	}
2419 	if (((apm_info.bios.flags & APM_BIOS_DISENGAGED) == 0)
2420 	    && (apm_info.connection_version > 0x0100)) {
2421 		error = apm_engage_power_management(APM_DEVICE_ALL, 0);
2422 		if (error)
2423 			apm_error("disengage power management", error);
2424 	}
2425 	misc_deregister(&apm_device);
2426 	remove_proc_entry("apm", NULL);
2427 	if (power_off)
2428 		pm_power_off = NULL;
2429 	if (kapmd_task) {
2430 		kthread_stop(kapmd_task);
2431 		kapmd_task = NULL;
2432 	}
2433 	pm_flags &= ~PM_APM;
2434 }
2435 
2436 module_init(apm_init);
2437 module_exit(apm_exit);
2438 
2439 MODULE_AUTHOR("Stephen Rothwell");
2440 MODULE_DESCRIPTION("Advanced Power Management");
2441 MODULE_LICENSE("GPL");
2442 module_param(debug, bool, 0644);
2443 MODULE_PARM_DESC(debug, "Enable debug mode");
2444 module_param(power_off, bool, 0444);
2445 MODULE_PARM_DESC(power_off, "Enable power off");
2446 module_param(bounce_interval, int, 0444);
2447 MODULE_PARM_DESC(bounce_interval,
2448 		"Set the number of ticks to ignore suspend bounces");
2449 module_param(allow_ints, bool, 0444);
2450 MODULE_PARM_DESC(allow_ints, "Allow interrupts during BIOS calls");
2451 module_param(broken_psr, bool, 0444);
2452 MODULE_PARM_DESC(broken_psr, "BIOS has a broken GetPowerStatus call");
2453 module_param(realmode_power_off, bool, 0444);
2454 MODULE_PARM_DESC(realmode_power_off,
2455 		"Switch to real mode before powering off");
2456 module_param(idle_threshold, int, 0444);
2457 MODULE_PARM_DESC(idle_threshold,
2458 	"System idle percentage above which to make APM BIOS idle calls");
2459 module_param(idle_period, int, 0444);
2460 MODULE_PARM_DESC(idle_period,
2461 	"Period (in sec/100) over which to caculate the idle percentage");
2462 module_param(smp, bool, 0444);
2463 MODULE_PARM_DESC(smp,
2464 	"Set this to enable APM use on an SMP platform. Use with caution on older systems");
2465 MODULE_ALIAS_MISCDEV(APM_MINOR_DEV);
2466