xref: /openbmc/linux/arch/x86/kernel/apm_32.c (revision b8bb76713ec50df2f11efee386e16f93d51e1076)
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.
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
482 		printk(KERN_NOTICE "apm: %s: unknown error code %#2.2x\n",
483 		       str, err);
484 }
485 
486 /*
487  * Lock APM functionality to physical CPU 0
488  */
489 
490 #ifdef CONFIG_SMP
491 
492 static cpumask_t apm_save_cpus(void)
493 {
494 	cpumask_t x = current->cpus_allowed;
495 	/* Some bioses don't like being called from CPU != 0 */
496 	set_cpus_allowed(current, cpumask_of_cpu(0));
497 	BUG_ON(smp_processor_id() != 0);
498 	return x;
499 }
500 
501 static inline void apm_restore_cpus(cpumask_t mask)
502 {
503 	set_cpus_allowed(current, mask);
504 }
505 
506 #else
507 
508 /*
509  *	No CPU lockdown needed on a uniprocessor
510  */
511 
512 #define apm_save_cpus()		(current->cpus_allowed)
513 #define apm_restore_cpus(x)	(void)(x)
514 
515 #endif
516 
517 /*
518  * These are the actual BIOS calls.  Depending on APM_ZERO_SEGS and
519  * apm_info.allow_ints, we are being really paranoid here!  Not only
520  * are interrupts disabled, but all the segment registers (except SS)
521  * are saved and zeroed this means that if the BIOS tries to reference
522  * any data without explicitly loading the segment registers, the kernel
523  * will fault immediately rather than have some unforeseen circumstances
524  * for the rest of the kernel.  And it will be very obvious!  :-) Doing
525  * this depends on CS referring to the same physical memory as DS so that
526  * DS can be zeroed before the call. Unfortunately, we can't do anything
527  * about the stack segment/pointer.  Also, we tell the compiler that
528  * everything could change.
529  *
530  * Also, we KNOW that for the non error case of apm_bios_call, there
531  * is no useful data returned in the low order 8 bits of eax.
532  */
533 
534 static inline unsigned long __apm_irq_save(void)
535 {
536 	unsigned long flags;
537 	local_save_flags(flags);
538 	if (apm_info.allow_ints) {
539 		if (irqs_disabled_flags(flags))
540 			local_irq_enable();
541 	} else
542 		local_irq_disable();
543 
544 	return flags;
545 }
546 
547 #define apm_irq_save(flags) \
548 	do { flags = __apm_irq_save(); } while (0)
549 
550 static inline void apm_irq_restore(unsigned long flags)
551 {
552 	if (irqs_disabled_flags(flags))
553 		local_irq_disable();
554 	else if (irqs_disabled())
555 		local_irq_enable();
556 }
557 
558 #ifdef APM_ZERO_SEGS
559 #	define APM_DECL_SEGS \
560 		unsigned int saved_fs; unsigned int saved_gs;
561 #	define APM_DO_SAVE_SEGS \
562 		savesegment(fs, saved_fs); savesegment(gs, saved_gs)
563 #	define APM_DO_RESTORE_SEGS \
564 		loadsegment(fs, saved_fs); loadsegment(gs, saved_gs)
565 #else
566 #	define APM_DECL_SEGS
567 #	define APM_DO_SAVE_SEGS
568 #	define APM_DO_RESTORE_SEGS
569 #endif
570 
571 /**
572  *	apm_bios_call	-	Make an APM BIOS 32bit call
573  *	@func: APM function to execute
574  *	@ebx_in: EBX register for call entry
575  *	@ecx_in: ECX register for call entry
576  *	@eax: EAX register return
577  *	@ebx: EBX register return
578  *	@ecx: ECX register return
579  *	@edx: EDX register return
580  *	@esi: ESI register return
581  *
582  *	Make an APM call using the 32bit protected mode interface. The
583  *	caller is responsible for knowing if APM BIOS is configured and
584  *	enabled. This call can disable interrupts for a long period of
585  *	time on some laptops.  The return value is in AH and the carry
586  *	flag is loaded into AL.  If there is an error, then the error
587  *	code is returned in AH (bits 8-15 of eax) and this function
588  *	returns non-zero.
589  */
590 
591 static u8 apm_bios_call(u32 func, u32 ebx_in, u32 ecx_in,
592 	u32 *eax, u32 *ebx, u32 *ecx, u32 *edx, u32 *esi)
593 {
594 	APM_DECL_SEGS
595 	unsigned long		flags;
596 	cpumask_t		cpus;
597 	int			cpu;
598 	struct desc_struct	save_desc_40;
599 	struct desc_struct	*gdt;
600 
601 	cpus = apm_save_cpus();
602 
603 	cpu = get_cpu();
604 	gdt = get_cpu_gdt_table(cpu);
605 	save_desc_40 = gdt[0x40 / 8];
606 	gdt[0x40 / 8] = bad_bios_desc;
607 
608 	apm_irq_save(flags);
609 	APM_DO_SAVE_SEGS;
610 	apm_bios_call_asm(func, ebx_in, ecx_in, eax, ebx, ecx, edx, esi);
611 	APM_DO_RESTORE_SEGS;
612 	apm_irq_restore(flags);
613 	gdt[0x40 / 8] = save_desc_40;
614 	put_cpu();
615 	apm_restore_cpus(cpus);
616 
617 	return *eax & 0xff;
618 }
619 
620 /**
621  *	apm_bios_call_simple	-	make a simple APM BIOS 32bit call
622  *	@func: APM function to invoke
623  *	@ebx_in: EBX register value for BIOS call
624  *	@ecx_in: ECX register value for BIOS call
625  *	@eax: EAX register on return from the BIOS call
626  *
627  *	Make a BIOS call that returns one value only, or just status.
628  *	If there is an error, then the error code is returned in AH
629  *	(bits 8-15 of eax) and this function returns non-zero. This is
630  *	used for simpler BIOS operations. This call may hold interrupts
631  *	off for a long time on some laptops.
632  */
633 
634 static u8 apm_bios_call_simple(u32 func, u32 ebx_in, u32 ecx_in, u32 *eax)
635 {
636 	u8			error;
637 	APM_DECL_SEGS
638 	unsigned long		flags;
639 	cpumask_t		cpus;
640 	int			cpu;
641 	struct desc_struct	save_desc_40;
642 	struct desc_struct	*gdt;
643 
644 	cpus = apm_save_cpus();
645 
646 	cpu = get_cpu();
647 	gdt = get_cpu_gdt_table(cpu);
648 	save_desc_40 = gdt[0x40 / 8];
649 	gdt[0x40 / 8] = bad_bios_desc;
650 
651 	apm_irq_save(flags);
652 	APM_DO_SAVE_SEGS;
653 	error = apm_bios_call_simple_asm(func, ebx_in, ecx_in, eax);
654 	APM_DO_RESTORE_SEGS;
655 	apm_irq_restore(flags);
656 	gdt[0x40 / 8] = save_desc_40;
657 	put_cpu();
658 	apm_restore_cpus(cpus);
659 	return error;
660 }
661 
662 /**
663  *	apm_driver_version	-	APM driver version
664  *	@val:	loaded with the APM version on return
665  *
666  *	Retrieve the APM version supported by the BIOS. This is only
667  *	supported for APM 1.1 or higher. An error indicates APM 1.0 is
668  *	probably present.
669  *
670  *	On entry val should point to a value indicating the APM driver
671  *	version with the high byte being the major and the low byte the
672  *	minor number both in BCD
673  *
674  *	On return it will hold the BIOS revision supported in the
675  *	same format.
676  */
677 
678 static int apm_driver_version(u_short *val)
679 {
680 	u32 eax;
681 
682 	if (apm_bios_call_simple(APM_FUNC_VERSION, 0, *val, &eax))
683 		return (eax >> 8) & 0xff;
684 	*val = eax;
685 	return APM_SUCCESS;
686 }
687 
688 /**
689  *	apm_get_event	-	get an APM event from the BIOS
690  *	@event: pointer to the event
691  *	@info: point to the event information
692  *
693  *	The APM BIOS provides a polled information for event
694  *	reporting. The BIOS expects to be polled at least every second
695  *	when events are pending. When a message is found the caller should
696  *	poll until no more messages are present.  However, this causes
697  *	problems on some laptops where a suspend event notification is
698  *	not cleared until it is acknowledged.
699  *
700  *	Additional information is returned in the info pointer, providing
701  *	that APM 1.2 is in use. If no messges are pending the value 0x80
702  *	is returned (No power management events pending).
703  */
704 
705 static int apm_get_event(apm_event_t *event, apm_eventinfo_t *info)
706 {
707 	u32 eax;
708 	u32 ebx;
709 	u32 ecx;
710 	u32 dummy;
711 
712 	if (apm_bios_call(APM_FUNC_GET_EVENT, 0, 0, &eax, &ebx, &ecx,
713 			  &dummy, &dummy))
714 		return (eax >> 8) & 0xff;
715 	*event = ebx;
716 	if (apm_info.connection_version < 0x0102)
717 		*info = ~0; /* indicate info not valid */
718 	else
719 		*info = ecx;
720 	return APM_SUCCESS;
721 }
722 
723 /**
724  *	set_power_state	-	set the power management state
725  *	@what: which items to transition
726  *	@state: state to transition to
727  *
728  *	Request an APM change of state for one or more system devices. The
729  *	processor state must be transitioned last of all. what holds the
730  *	class of device in the upper byte and the device number (0xFF for
731  *	all) for the object to be transitioned.
732  *
733  *	The state holds the state to transition to, which may in fact
734  *	be an acceptance of a BIOS requested state change.
735  */
736 
737 static int set_power_state(u_short what, u_short state)
738 {
739 	u32 eax;
740 
741 	if (apm_bios_call_simple(APM_FUNC_SET_STATE, what, state, &eax))
742 		return (eax >> 8) & 0xff;
743 	return APM_SUCCESS;
744 }
745 
746 /**
747  *	set_system_power_state - set system wide power state
748  *	@state: which state to enter
749  *
750  *	Transition the entire system into a new APM power state.
751  */
752 
753 static int set_system_power_state(u_short state)
754 {
755 	return set_power_state(APM_DEVICE_ALL, state);
756 }
757 
758 /**
759  *	apm_do_idle	-	perform power saving
760  *
761  *	This function notifies the BIOS that the processor is (in the view
762  *	of the OS) idle. It returns -1 in the event that the BIOS refuses
763  *	to handle the idle request. On a success the function returns 1
764  *	if the BIOS did clock slowing or 0 otherwise.
765  */
766 
767 static int apm_do_idle(void)
768 {
769 	u32 eax;
770 	u8 ret = 0;
771 	int idled = 0;
772 	int polling;
773 
774 	polling = !!(current_thread_info()->status & TS_POLLING);
775 	if (polling) {
776 		current_thread_info()->status &= ~TS_POLLING;
777 		/*
778 		 * TS_POLLING-cleared state must be visible before we
779 		 * test NEED_RESCHED:
780 		 */
781 		smp_mb();
782 	}
783 	if (!need_resched()) {
784 		idled = 1;
785 		ret = apm_bios_call_simple(APM_FUNC_IDLE, 0, 0, &eax);
786 	}
787 	if (polling)
788 		current_thread_info()->status |= TS_POLLING;
789 
790 	if (!idled)
791 		return 0;
792 
793 	if (ret) {
794 		static unsigned long t;
795 
796 		/* This always fails on some SMP boards running UP kernels.
797 		 * Only report the failure the first 5 times.
798 		 */
799 		if (++t < 5) {
800 			printk(KERN_DEBUG "apm_do_idle failed (%d)\n",
801 			       (eax >> 8) & 0xff);
802 			t = jiffies;
803 		}
804 		return -1;
805 	}
806 	clock_slowed = (apm_info.bios.flags & APM_IDLE_SLOWS_CLOCK) != 0;
807 	return clock_slowed;
808 }
809 
810 /**
811  *	apm_do_busy	-	inform the BIOS the CPU is busy
812  *
813  *	Request that the BIOS brings the CPU back to full performance.
814  */
815 
816 static void apm_do_busy(void)
817 {
818 	u32 dummy;
819 
820 	if (clock_slowed || ALWAYS_CALL_BUSY) {
821 		(void)apm_bios_call_simple(APM_FUNC_BUSY, 0, 0, &dummy);
822 		clock_slowed = 0;
823 	}
824 }
825 
826 /*
827  * If no process has really been interested in
828  * the CPU for some time, we want to call BIOS
829  * power management - we probably want
830  * to conserve power.
831  */
832 #define IDLE_CALC_LIMIT	(HZ * 100)
833 #define IDLE_LEAKY_MAX	16
834 
835 static void (*original_pm_idle)(void) __read_mostly;
836 
837 /**
838  * apm_cpu_idle		-	cpu idling for APM capable Linux
839  *
840  * This is the idling function the kernel executes when APM is available. It
841  * tries to do BIOS powermanagement based on the average system idle time.
842  * Furthermore it calls the system default idle routine.
843  */
844 
845 static void apm_cpu_idle(void)
846 {
847 	static int use_apm_idle; /* = 0 */
848 	static unsigned int last_jiffies; /* = 0 */
849 	static unsigned int last_stime; /* = 0 */
850 
851 	int apm_idle_done = 0;
852 	unsigned int jiffies_since_last_check = jiffies - last_jiffies;
853 	unsigned int bucket;
854 
855 recalc:
856 	if (jiffies_since_last_check > IDLE_CALC_LIMIT) {
857 		use_apm_idle = 0;
858 		last_jiffies = jiffies;
859 		last_stime = current->stime;
860 	} else if (jiffies_since_last_check > idle_period) {
861 		unsigned int idle_percentage;
862 
863 		idle_percentage = current->stime - last_stime;
864 		idle_percentage *= 100;
865 		idle_percentage /= jiffies_since_last_check;
866 		use_apm_idle = (idle_percentage > idle_threshold);
867 		if (apm_info.forbid_idle)
868 			use_apm_idle = 0;
869 		last_jiffies = jiffies;
870 		last_stime = current->stime;
871 	}
872 
873 	bucket = IDLE_LEAKY_MAX;
874 
875 	while (!need_resched()) {
876 		if (use_apm_idle) {
877 			unsigned int t;
878 
879 			t = jiffies;
880 			switch (apm_do_idle()) {
881 			case 0:
882 				apm_idle_done = 1;
883 				if (t != jiffies) {
884 					if (bucket) {
885 						bucket = IDLE_LEAKY_MAX;
886 						continue;
887 					}
888 				} else if (bucket) {
889 					bucket--;
890 					continue;
891 				}
892 				break;
893 			case 1:
894 				apm_idle_done = 1;
895 				break;
896 			default: /* BIOS refused */
897 				break;
898 			}
899 		}
900 		if (original_pm_idle)
901 			original_pm_idle();
902 		else
903 			default_idle();
904 		local_irq_disable();
905 		jiffies_since_last_check = jiffies - last_jiffies;
906 		if (jiffies_since_last_check > idle_period)
907 			goto recalc;
908 	}
909 
910 	if (apm_idle_done)
911 		apm_do_busy();
912 
913 	local_irq_enable();
914 }
915 
916 /**
917  *	apm_power_off	-	ask the BIOS to power off
918  *
919  *	Handle the power off sequence. This is the one piece of code we
920  *	will execute even on SMP machines. In order to deal with BIOS
921  *	bugs we support real mode APM BIOS power off calls. We also make
922  *	the SMP call on CPU0 as some systems will only honour this call
923  *	on their first cpu.
924  */
925 
926 static void apm_power_off(void)
927 {
928 	unsigned char po_bios_call[] = {
929 		0xb8, 0x00, 0x10,	/* movw  $0x1000,ax  */
930 		0x8e, 0xd0,		/* movw  ax,ss       */
931 		0xbc, 0x00, 0xf0,	/* movw  $0xf000,sp  */
932 		0xb8, 0x07, 0x53,	/* movw  $0x5307,ax  */
933 		0xbb, 0x01, 0x00,	/* movw  $0x0001,bx  */
934 		0xb9, 0x03, 0x00,	/* movw  $0x0003,cx  */
935 		0xcd, 0x15		/* int   $0x15       */
936 	};
937 
938 	/* Some bioses don't like being called from CPU != 0 */
939 	if (apm_info.realmode_power_off) {
940 		(void)apm_save_cpus();
941 		machine_real_restart(po_bios_call, sizeof(po_bios_call));
942 	} else {
943 		(void)set_system_power_state(APM_STATE_OFF);
944 	}
945 }
946 
947 #ifdef CONFIG_APM_DO_ENABLE
948 
949 /**
950  *	apm_enable_power_management - enable BIOS APM power management
951  *	@enable: enable yes/no
952  *
953  *	Enable or disable the APM BIOS power services.
954  */
955 
956 static int apm_enable_power_management(int enable)
957 {
958 	u32 eax;
959 
960 	if ((enable == 0) && (apm_info.bios.flags & APM_BIOS_DISENGAGED))
961 		return APM_NOT_ENGAGED;
962 	if (apm_bios_call_simple(APM_FUNC_ENABLE_PM, APM_DEVICE_BALL,
963 				 enable, &eax))
964 		return (eax >> 8) & 0xff;
965 	if (enable)
966 		apm_info.bios.flags &= ~APM_BIOS_DISABLED;
967 	else
968 		apm_info.bios.flags |= APM_BIOS_DISABLED;
969 	return APM_SUCCESS;
970 }
971 #endif
972 
973 /**
974  *	apm_get_power_status	-	get current power state
975  *	@status: returned status
976  *	@bat: battery info
977  *	@life: estimated life
978  *
979  *	Obtain the current power status from the APM BIOS. We return a
980  *	status which gives the rough battery status, and current power
981  *	source. The bat value returned give an estimate as a percentage
982  *	of life and a status value for the battery. The estimated life
983  *	if reported is a lifetime in secodnds/minutes at current powwer
984  *	consumption.
985  */
986 
987 static int apm_get_power_status(u_short *status, u_short *bat, u_short *life)
988 {
989 	u32 eax;
990 	u32 ebx;
991 	u32 ecx;
992 	u32 edx;
993 	u32 dummy;
994 
995 	if (apm_info.get_power_status_broken)
996 		return APM_32_UNSUPPORTED;
997 	if (apm_bios_call(APM_FUNC_GET_STATUS, APM_DEVICE_ALL, 0,
998 			  &eax, &ebx, &ecx, &edx, &dummy))
999 		return (eax >> 8) & 0xff;
1000 	*status = ebx;
1001 	*bat = ecx;
1002 	if (apm_info.get_power_status_swabinminutes) {
1003 		*life = swab16((u16)edx);
1004 		*life |= 0x8000;
1005 	} else
1006 		*life = edx;
1007 	return APM_SUCCESS;
1008 }
1009 
1010 #if 0
1011 static int apm_get_battery_status(u_short which, u_short *status,
1012 				  u_short *bat, u_short *life, u_short *nbat)
1013 {
1014 	u32 eax;
1015 	u32 ebx;
1016 	u32 ecx;
1017 	u32 edx;
1018 	u32 esi;
1019 
1020 	if (apm_info.connection_version < 0x0102) {
1021 		/* pretend we only have one battery. */
1022 		if (which != 1)
1023 			return APM_BAD_DEVICE;
1024 		*nbat = 1;
1025 		return apm_get_power_status(status, bat, life);
1026 	}
1027 
1028 	if (apm_bios_call(APM_FUNC_GET_STATUS, (0x8000 | (which)), 0, &eax,
1029 			  &ebx, &ecx, &edx, &esi))
1030 		return (eax >> 8) & 0xff;
1031 	*status = ebx;
1032 	*bat = ecx;
1033 	*life = edx;
1034 	*nbat = esi;
1035 	return APM_SUCCESS;
1036 }
1037 #endif
1038 
1039 /**
1040  *	apm_engage_power_management	-	enable PM on a device
1041  *	@device: identity of device
1042  *	@enable: on/off
1043  *
1044  *	Activate or deactive power management on either a specific device
1045  *	or the entire system (%APM_DEVICE_ALL).
1046  */
1047 
1048 static int apm_engage_power_management(u_short device, int enable)
1049 {
1050 	u32 eax;
1051 
1052 	if ((enable == 0) && (device == APM_DEVICE_ALL)
1053 	    && (apm_info.bios.flags & APM_BIOS_DISABLED))
1054 		return APM_DISABLED;
1055 	if (apm_bios_call_simple(APM_FUNC_ENGAGE_PM, device, enable, &eax))
1056 		return (eax >> 8) & 0xff;
1057 	if (device == APM_DEVICE_ALL) {
1058 		if (enable)
1059 			apm_info.bios.flags &= ~APM_BIOS_DISENGAGED;
1060 		else
1061 			apm_info.bios.flags |= APM_BIOS_DISENGAGED;
1062 	}
1063 	return APM_SUCCESS;
1064 }
1065 
1066 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1067 
1068 /**
1069  *	apm_console_blank	-	blank the display
1070  *	@blank: on/off
1071  *
1072  *	Attempt to blank the console, firstly by blanking just video device
1073  *	zero, and if that fails (some BIOSes don't support it) then it blanks
1074  *	all video devices. Typically the BIOS will do laptop backlight and
1075  *	monitor powerdown for us.
1076  */
1077 
1078 static int apm_console_blank(int blank)
1079 {
1080 	int error = APM_NOT_ENGAGED; /* silence gcc */
1081 	int i;
1082 	u_short state;
1083 	static const u_short dev[3] = { 0x100, 0x1FF, 0x101 };
1084 
1085 	state = blank ? APM_STATE_STANDBY : APM_STATE_READY;
1086 
1087 	for (i = 0; i < ARRAY_SIZE(dev); i++) {
1088 		error = set_power_state(dev[i], state);
1089 
1090 		if ((error == APM_SUCCESS) || (error == APM_NO_ERROR))
1091 			return 1;
1092 
1093 		if (error == APM_NOT_ENGAGED)
1094 			break;
1095 	}
1096 
1097 	if (error == APM_NOT_ENGAGED) {
1098 		static int tried;
1099 		int eng_error;
1100 		if (tried++ == 0) {
1101 			eng_error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1102 			if (eng_error) {
1103 				apm_error("set display", error);
1104 				apm_error("engage interface", eng_error);
1105 				return 0;
1106 			} else
1107 				return apm_console_blank(blank);
1108 		}
1109 	}
1110 	apm_error("set display", error);
1111 	return 0;
1112 }
1113 #endif
1114 
1115 static int queue_empty(struct apm_user *as)
1116 {
1117 	return as->event_head == as->event_tail;
1118 }
1119 
1120 static apm_event_t get_queued_event(struct apm_user *as)
1121 {
1122 	if (++as->event_tail >= APM_MAX_EVENTS)
1123 		as->event_tail = 0;
1124 	return as->events[as->event_tail];
1125 }
1126 
1127 static void queue_event(apm_event_t event, struct apm_user *sender)
1128 {
1129 	struct apm_user *as;
1130 
1131 	spin_lock(&user_list_lock);
1132 	if (user_list == NULL)
1133 		goto out;
1134 	for (as = user_list; as != NULL; as = as->next) {
1135 		if ((as == sender) || (!as->reader))
1136 			continue;
1137 		if (++as->event_head >= APM_MAX_EVENTS)
1138 			as->event_head = 0;
1139 
1140 		if (as->event_head == as->event_tail) {
1141 			static int notified;
1142 
1143 			if (notified++ == 0)
1144 			    printk(KERN_ERR "apm: an event queue overflowed\n");
1145 			if (++as->event_tail >= APM_MAX_EVENTS)
1146 				as->event_tail = 0;
1147 		}
1148 		as->events[as->event_head] = event;
1149 		if (!as->suser || !as->writer)
1150 			continue;
1151 		switch (event) {
1152 		case APM_SYS_SUSPEND:
1153 		case APM_USER_SUSPEND:
1154 			as->suspends_pending++;
1155 			suspends_pending++;
1156 			break;
1157 
1158 		case APM_SYS_STANDBY:
1159 		case APM_USER_STANDBY:
1160 			as->standbys_pending++;
1161 			standbys_pending++;
1162 			break;
1163 		}
1164 	}
1165 	wake_up_interruptible(&apm_waitqueue);
1166 out:
1167 	spin_unlock(&user_list_lock);
1168 }
1169 
1170 static void reinit_timer(void)
1171 {
1172 #ifdef INIT_TIMER_AFTER_SUSPEND
1173 	unsigned long flags;
1174 
1175 	spin_lock_irqsave(&i8253_lock, flags);
1176 	/* set the clock to HZ */
1177 	outb_pit(0x34, PIT_MODE);		/* binary, mode 2, LSB/MSB, ch 0 */
1178 	udelay(10);
1179 	outb_pit(LATCH & 0xff, PIT_CH0);	/* LSB */
1180 	udelay(10);
1181 	outb_pit(LATCH >> 8, PIT_CH0);	/* MSB */
1182 	udelay(10);
1183 	spin_unlock_irqrestore(&i8253_lock, flags);
1184 #endif
1185 }
1186 
1187 static int suspend(int vetoable)
1188 {
1189 	int err;
1190 	struct apm_user	*as;
1191 
1192 	device_suspend(PMSG_SUSPEND);
1193 
1194 	device_power_down(PMSG_SUSPEND);
1195 
1196 	local_irq_disable();
1197 	sysdev_suspend(PMSG_SUSPEND);
1198 
1199 	local_irq_enable();
1200 
1201 	save_processor_state();
1202 	err = set_system_power_state(APM_STATE_SUSPEND);
1203 	ignore_normal_resume = 1;
1204 	restore_processor_state();
1205 
1206 	local_irq_disable();
1207 	reinit_timer();
1208 
1209 	if (err == APM_NO_ERROR)
1210 		err = APM_SUCCESS;
1211 	if (err != APM_SUCCESS)
1212 		apm_error("suspend", err);
1213 	err = (err == APM_SUCCESS) ? 0 : -EIO;
1214 
1215 	sysdev_resume();
1216 	local_irq_enable();
1217 
1218 	device_power_up(PMSG_RESUME);
1219 
1220 	device_resume(PMSG_RESUME);
1221 	queue_event(APM_NORMAL_RESUME, NULL);
1222 	spin_lock(&user_list_lock);
1223 	for (as = user_list; as != NULL; as = as->next) {
1224 		as->suspend_wait = 0;
1225 		as->suspend_result = err;
1226 	}
1227 	spin_unlock(&user_list_lock);
1228 	wake_up_interruptible(&apm_suspend_waitqueue);
1229 	return err;
1230 }
1231 
1232 static void standby(void)
1233 {
1234 	int err;
1235 
1236 	device_power_down(PMSG_SUSPEND);
1237 
1238 	local_irq_disable();
1239 	sysdev_suspend(PMSG_SUSPEND);
1240 	local_irq_enable();
1241 
1242 	err = set_system_power_state(APM_STATE_STANDBY);
1243 	if ((err != APM_SUCCESS) && (err != APM_NO_ERROR))
1244 		apm_error("standby", err);
1245 
1246 	local_irq_disable();
1247 	sysdev_resume();
1248 	local_irq_enable();
1249 
1250 	device_power_up(PMSG_RESUME);
1251 }
1252 
1253 static apm_event_t get_event(void)
1254 {
1255 	int error;
1256 	apm_event_t event = APM_NO_EVENTS; /* silence gcc */
1257 	apm_eventinfo_t	info;
1258 
1259 	static int notified;
1260 
1261 	/* we don't use the eventinfo */
1262 	error = apm_get_event(&event, &info);
1263 	if (error == APM_SUCCESS)
1264 		return event;
1265 
1266 	if ((error != APM_NO_EVENTS) && (notified++ == 0))
1267 		apm_error("get_event", error);
1268 
1269 	return 0;
1270 }
1271 
1272 static void check_events(void)
1273 {
1274 	apm_event_t event;
1275 	static unsigned long last_resume;
1276 	static int ignore_bounce;
1277 
1278 	while ((event = get_event()) != 0) {
1279 		if (debug) {
1280 			if (event <= NR_APM_EVENT_NAME)
1281 				printk(KERN_DEBUG "apm: received %s notify\n",
1282 				       apm_event_name[event - 1]);
1283 			else
1284 				printk(KERN_DEBUG "apm: received unknown "
1285 				       "event 0x%02x\n", event);
1286 		}
1287 		if (ignore_bounce
1288 		    && (time_after(jiffies, last_resume + bounce_interval)))
1289 			ignore_bounce = 0;
1290 
1291 		switch (event) {
1292 		case APM_SYS_STANDBY:
1293 		case APM_USER_STANDBY:
1294 			queue_event(event, NULL);
1295 			if (standbys_pending <= 0)
1296 				standby();
1297 			break;
1298 
1299 		case APM_USER_SUSPEND:
1300 #ifdef CONFIG_APM_IGNORE_USER_SUSPEND
1301 			if (apm_info.connection_version > 0x100)
1302 				set_system_power_state(APM_STATE_REJECT);
1303 			break;
1304 #endif
1305 		case APM_SYS_SUSPEND:
1306 			if (ignore_bounce) {
1307 				if (apm_info.connection_version > 0x100)
1308 					set_system_power_state(APM_STATE_REJECT);
1309 				break;
1310 			}
1311 			/*
1312 			 * If we are already processing a SUSPEND,
1313 			 * then further SUSPEND events from the BIOS
1314 			 * will be ignored.  We also return here to
1315 			 * cope with the fact that the Thinkpads keep
1316 			 * sending a SUSPEND event until something else
1317 			 * happens!
1318 			 */
1319 			if (ignore_sys_suspend)
1320 				return;
1321 			ignore_sys_suspend = 1;
1322 			queue_event(event, NULL);
1323 			if (suspends_pending <= 0)
1324 				(void) suspend(1);
1325 			break;
1326 
1327 		case APM_NORMAL_RESUME:
1328 		case APM_CRITICAL_RESUME:
1329 		case APM_STANDBY_RESUME:
1330 			ignore_sys_suspend = 0;
1331 			last_resume = jiffies;
1332 			ignore_bounce = 1;
1333 			if ((event != APM_NORMAL_RESUME)
1334 			    || (ignore_normal_resume == 0)) {
1335 				device_resume(PMSG_RESUME);
1336 				queue_event(event, NULL);
1337 			}
1338 			ignore_normal_resume = 0;
1339 			break;
1340 
1341 		case APM_CAPABILITY_CHANGE:
1342 		case APM_LOW_BATTERY:
1343 		case APM_POWER_STATUS_CHANGE:
1344 			queue_event(event, NULL);
1345 			/* If needed, notify drivers here */
1346 			break;
1347 
1348 		case APM_UPDATE_TIME:
1349 			break;
1350 
1351 		case APM_CRITICAL_SUSPEND:
1352 			/*
1353 			 * We are not allowed to reject a critical suspend.
1354 			 */
1355 			(void)suspend(0);
1356 			break;
1357 		}
1358 	}
1359 }
1360 
1361 static void apm_event_handler(void)
1362 {
1363 	static int pending_count = 4;
1364 	int err;
1365 
1366 	if ((standbys_pending > 0) || (suspends_pending > 0)) {
1367 		if ((apm_info.connection_version > 0x100) &&
1368 		    (pending_count-- <= 0)) {
1369 			pending_count = 4;
1370 			if (debug)
1371 				printk(KERN_DEBUG "apm: setting state busy\n");
1372 			err = set_system_power_state(APM_STATE_BUSY);
1373 			if (err)
1374 				apm_error("busy", err);
1375 		}
1376 	} else
1377 		pending_count = 4;
1378 	check_events();
1379 }
1380 
1381 /*
1382  * This is the APM thread main loop.
1383  */
1384 
1385 static void apm_mainloop(void)
1386 {
1387 	DECLARE_WAITQUEUE(wait, current);
1388 
1389 	add_wait_queue(&apm_waitqueue, &wait);
1390 	set_current_state(TASK_INTERRUPTIBLE);
1391 	for (;;) {
1392 		schedule_timeout(APM_CHECK_TIMEOUT);
1393 		if (kthread_should_stop())
1394 			break;
1395 		/*
1396 		 * Ok, check all events, check for idle (and mark us sleeping
1397 		 * so as not to count towards the load average)..
1398 		 */
1399 		set_current_state(TASK_INTERRUPTIBLE);
1400 		apm_event_handler();
1401 	}
1402 	remove_wait_queue(&apm_waitqueue, &wait);
1403 }
1404 
1405 static int check_apm_user(struct apm_user *as, const char *func)
1406 {
1407 	if (as == NULL || as->magic != APM_BIOS_MAGIC) {
1408 		printk(KERN_ERR "apm: %s passed bad filp\n", func);
1409 		return 1;
1410 	}
1411 	return 0;
1412 }
1413 
1414 static ssize_t do_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
1415 {
1416 	struct apm_user *as;
1417 	int i;
1418 	apm_event_t event;
1419 
1420 	as = fp->private_data;
1421 	if (check_apm_user(as, "read"))
1422 		return -EIO;
1423 	if ((int)count < sizeof(apm_event_t))
1424 		return -EINVAL;
1425 	if ((queue_empty(as)) && (fp->f_flags & O_NONBLOCK))
1426 		return -EAGAIN;
1427 	wait_event_interruptible(apm_waitqueue, !queue_empty(as));
1428 	i = count;
1429 	while ((i >= sizeof(event)) && !queue_empty(as)) {
1430 		event = get_queued_event(as);
1431 		if (copy_to_user(buf, &event, sizeof(event))) {
1432 			if (i < count)
1433 				break;
1434 			return -EFAULT;
1435 		}
1436 		switch (event) {
1437 		case APM_SYS_SUSPEND:
1438 		case APM_USER_SUSPEND:
1439 			as->suspends_read++;
1440 			break;
1441 
1442 		case APM_SYS_STANDBY:
1443 		case APM_USER_STANDBY:
1444 			as->standbys_read++;
1445 			break;
1446 		}
1447 		buf += sizeof(event);
1448 		i -= sizeof(event);
1449 	}
1450 	if (i < count)
1451 		return count - i;
1452 	if (signal_pending(current))
1453 		return -ERESTARTSYS;
1454 	return 0;
1455 }
1456 
1457 static unsigned int do_poll(struct file *fp, poll_table *wait)
1458 {
1459 	struct apm_user *as;
1460 
1461 	as = fp->private_data;
1462 	if (check_apm_user(as, "poll"))
1463 		return 0;
1464 	poll_wait(fp, &apm_waitqueue, wait);
1465 	if (!queue_empty(as))
1466 		return POLLIN | POLLRDNORM;
1467 	return 0;
1468 }
1469 
1470 static long do_ioctl(struct file *filp, u_int cmd, u_long arg)
1471 {
1472 	struct apm_user *as;
1473 	int ret;
1474 
1475 	as = filp->private_data;
1476 	if (check_apm_user(as, "ioctl"))
1477 		return -EIO;
1478 	if (!as->suser || !as->writer)
1479 		return -EPERM;
1480 	switch (cmd) {
1481 	case APM_IOC_STANDBY:
1482 		lock_kernel();
1483 		if (as->standbys_read > 0) {
1484 			as->standbys_read--;
1485 			as->standbys_pending--;
1486 			standbys_pending--;
1487 		} else
1488 			queue_event(APM_USER_STANDBY, as);
1489 		if (standbys_pending <= 0)
1490 			standby();
1491 		unlock_kernel();
1492 		break;
1493 	case APM_IOC_SUSPEND:
1494 		lock_kernel();
1495 		if (as->suspends_read > 0) {
1496 			as->suspends_read--;
1497 			as->suspends_pending--;
1498 			suspends_pending--;
1499 		} else
1500 			queue_event(APM_USER_SUSPEND, as);
1501 		if (suspends_pending <= 0) {
1502 			ret = suspend(1);
1503 		} else {
1504 			as->suspend_wait = 1;
1505 			wait_event_interruptible(apm_suspend_waitqueue,
1506 					as->suspend_wait == 0);
1507 			ret = as->suspend_result;
1508 		}
1509 		unlock_kernel();
1510 		return ret;
1511 	default:
1512 		return -ENOTTY;
1513 	}
1514 	return 0;
1515 }
1516 
1517 static int do_release(struct inode *inode, struct file *filp)
1518 {
1519 	struct apm_user *as;
1520 
1521 	as = filp->private_data;
1522 	if (check_apm_user(as, "release"))
1523 		return 0;
1524 	filp->private_data = NULL;
1525 	if (as->standbys_pending > 0) {
1526 		standbys_pending -= as->standbys_pending;
1527 		if (standbys_pending <= 0)
1528 			standby();
1529 	}
1530 	if (as->suspends_pending > 0) {
1531 		suspends_pending -= as->suspends_pending;
1532 		if (suspends_pending <= 0)
1533 			(void) suspend(1);
1534 	}
1535 	spin_lock(&user_list_lock);
1536 	if (user_list == as)
1537 		user_list = as->next;
1538 	else {
1539 		struct apm_user *as1;
1540 
1541 		for (as1 = user_list;
1542 		     (as1 != NULL) && (as1->next != as);
1543 		     as1 = as1->next)
1544 			;
1545 		if (as1 == NULL)
1546 			printk(KERN_ERR "apm: filp not in user list\n");
1547 		else
1548 			as1->next = as->next;
1549 	}
1550 	spin_unlock(&user_list_lock);
1551 	kfree(as);
1552 	return 0;
1553 }
1554 
1555 static int do_open(struct inode *inode, struct file *filp)
1556 {
1557 	struct apm_user *as;
1558 
1559 	lock_kernel();
1560 	as = kmalloc(sizeof(*as), GFP_KERNEL);
1561 	if (as == NULL) {
1562 		printk(KERN_ERR "apm: cannot allocate struct of size %d bytes\n",
1563 		       sizeof(*as));
1564 		       unlock_kernel();
1565 		return -ENOMEM;
1566 	}
1567 	as->magic = APM_BIOS_MAGIC;
1568 	as->event_tail = as->event_head = 0;
1569 	as->suspends_pending = as->standbys_pending = 0;
1570 	as->suspends_read = as->standbys_read = 0;
1571 	/*
1572 	 * XXX - this is a tiny bit broken, when we consider BSD
1573 	 * process accounting. If the device is opened by root, we
1574 	 * instantly flag that we used superuser privs. Who knows,
1575 	 * we might close the device immediately without doing a
1576 	 * privileged operation -- cevans
1577 	 */
1578 	as->suser = capable(CAP_SYS_ADMIN);
1579 	as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
1580 	as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
1581 	spin_lock(&user_list_lock);
1582 	as->next = user_list;
1583 	user_list = as;
1584 	spin_unlock(&user_list_lock);
1585 	filp->private_data = as;
1586 	unlock_kernel();
1587 	return 0;
1588 }
1589 
1590 static int proc_apm_show(struct seq_file *m, void *v)
1591 {
1592 	unsigned short	bx;
1593 	unsigned short	cx;
1594 	unsigned short	dx;
1595 	int		error;
1596 	unsigned short  ac_line_status = 0xff;
1597 	unsigned short  battery_status = 0xff;
1598 	unsigned short  battery_flag   = 0xff;
1599 	int		percentage     = -1;
1600 	int             time_units     = -1;
1601 	char            *units         = "?";
1602 
1603 	if ((num_online_cpus() == 1) &&
1604 	    !(error = apm_get_power_status(&bx, &cx, &dx))) {
1605 		ac_line_status = (bx >> 8) & 0xff;
1606 		battery_status = bx & 0xff;
1607 		if ((cx & 0xff) != 0xff)
1608 			percentage = cx & 0xff;
1609 
1610 		if (apm_info.connection_version > 0x100) {
1611 			battery_flag = (cx >> 8) & 0xff;
1612 			if (dx != 0xffff) {
1613 				units = (dx & 0x8000) ? "min" : "sec";
1614 				time_units = dx & 0x7fff;
1615 			}
1616 		}
1617 	}
1618 	/* Arguments, with symbols from linux/apm_bios.h.  Information is
1619 	   from the Get Power Status (0x0a) call unless otherwise noted.
1620 
1621 	   0) Linux driver version (this will change if format changes)
1622 	   1) APM BIOS Version.  Usually 1.0, 1.1 or 1.2.
1623 	   2) APM flags from APM Installation Check (0x00):
1624 	      bit 0: APM_16_BIT_SUPPORT
1625 	      bit 1: APM_32_BIT_SUPPORT
1626 	      bit 2: APM_IDLE_SLOWS_CLOCK
1627 	      bit 3: APM_BIOS_DISABLED
1628 	      bit 4: APM_BIOS_DISENGAGED
1629 	   3) AC line status
1630 	      0x00: Off-line
1631 	      0x01: On-line
1632 	      0x02: On backup power (BIOS >= 1.1 only)
1633 	      0xff: Unknown
1634 	   4) Battery status
1635 	      0x00: High
1636 	      0x01: Low
1637 	      0x02: Critical
1638 	      0x03: Charging
1639 	      0x04: Selected battery not present (BIOS >= 1.2 only)
1640 	      0xff: Unknown
1641 	   5) Battery flag
1642 	      bit 0: High
1643 	      bit 1: Low
1644 	      bit 2: Critical
1645 	      bit 3: Charging
1646 	      bit 7: No system battery
1647 	      0xff: Unknown
1648 	   6) Remaining battery life (percentage of charge):
1649 	      0-100: valid
1650 	      -1: Unknown
1651 	   7) Remaining battery life (time units):
1652 	      Number of remaining minutes or seconds
1653 	      -1: Unknown
1654 	   8) min = minutes; sec = seconds */
1655 
1656 	seq_printf(m, "%s %d.%d 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
1657 		   driver_version,
1658 		   (apm_info.bios.version >> 8) & 0xff,
1659 		   apm_info.bios.version & 0xff,
1660 		   apm_info.bios.flags,
1661 		   ac_line_status,
1662 		   battery_status,
1663 		   battery_flag,
1664 		   percentage,
1665 		   time_units,
1666 		   units);
1667 	return 0;
1668 }
1669 
1670 static int proc_apm_open(struct inode *inode, struct file *file)
1671 {
1672 	return single_open(file, proc_apm_show, NULL);
1673 }
1674 
1675 static const struct file_operations apm_file_ops = {
1676 	.owner		= THIS_MODULE,
1677 	.open		= proc_apm_open,
1678 	.read		= seq_read,
1679 	.llseek		= seq_lseek,
1680 	.release	= single_release,
1681 };
1682 
1683 static int apm(void *unused)
1684 {
1685 	unsigned short	bx;
1686 	unsigned short	cx;
1687 	unsigned short	dx;
1688 	int		error;
1689 	char 		*power_stat;
1690 	char 		*bat_stat;
1691 
1692 #ifdef CONFIG_SMP
1693 	/* 2002/08/01 - WT
1694 	 * This is to avoid random crashes at boot time during initialization
1695 	 * on SMP systems in case of "apm=power-off" mode. Seen on ASUS A7M266D.
1696 	 * Some bioses don't like being called from CPU != 0.
1697 	 * Method suggested by Ingo Molnar.
1698 	 */
1699 	set_cpus_allowed(current, cpumask_of_cpu(0));
1700 	BUG_ON(smp_processor_id() != 0);
1701 #endif
1702 
1703 	if (apm_info.connection_version == 0) {
1704 		apm_info.connection_version = apm_info.bios.version;
1705 		if (apm_info.connection_version > 0x100) {
1706 			/*
1707 			 * We only support BIOSs up to version 1.2
1708 			 */
1709 			if (apm_info.connection_version > 0x0102)
1710 				apm_info.connection_version = 0x0102;
1711 			error = apm_driver_version(&apm_info.connection_version);
1712 			if (error != APM_SUCCESS) {
1713 				apm_error("driver version", error);
1714 				/* Fall back to an APM 1.0 connection. */
1715 				apm_info.connection_version = 0x100;
1716 			}
1717 		}
1718 	}
1719 
1720 	if (debug)
1721 		printk(KERN_INFO "apm: Connection version %d.%d\n",
1722 			(apm_info.connection_version >> 8) & 0xff,
1723 			apm_info.connection_version & 0xff);
1724 
1725 #ifdef CONFIG_APM_DO_ENABLE
1726 	if (apm_info.bios.flags & APM_BIOS_DISABLED) {
1727 		/*
1728 		 * This call causes my NEC UltraLite Versa 33/C to hang if it
1729 		 * is booted with PM disabled but not in the docking station.
1730 		 * Unfortunate ...
1731 		 */
1732 		error = apm_enable_power_management(1);
1733 		if (error) {
1734 			apm_error("enable power management", error);
1735 			return -1;
1736 		}
1737 	}
1738 #endif
1739 
1740 	if ((apm_info.bios.flags & APM_BIOS_DISENGAGED)
1741 	    && (apm_info.connection_version > 0x0100)) {
1742 		error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1743 		if (error) {
1744 			apm_error("engage power management", error);
1745 			return -1;
1746 		}
1747 	}
1748 
1749 	if (debug && (num_online_cpus() == 1 || smp)) {
1750 		error = apm_get_power_status(&bx, &cx, &dx);
1751 		if (error)
1752 			printk(KERN_INFO "apm: power status not available\n");
1753 		else {
1754 			switch ((bx >> 8) & 0xff) {
1755 			case 0:
1756 				power_stat = "off line";
1757 				break;
1758 			case 1:
1759 				power_stat = "on line";
1760 				break;
1761 			case 2:
1762 				power_stat = "on backup power";
1763 				break;
1764 			default:
1765 				power_stat = "unknown";
1766 				break;
1767 			}
1768 			switch (bx & 0xff) {
1769 			case 0:
1770 				bat_stat = "high";
1771 				break;
1772 			case 1:
1773 				bat_stat = "low";
1774 				break;
1775 			case 2:
1776 				bat_stat = "critical";
1777 				break;
1778 			case 3:
1779 				bat_stat = "charging";
1780 				break;
1781 			default:
1782 				bat_stat = "unknown";
1783 				break;
1784 			}
1785 			printk(KERN_INFO
1786 			       "apm: AC %s, battery status %s, battery life ",
1787 			       power_stat, bat_stat);
1788 			if ((cx & 0xff) == 0xff)
1789 				printk("unknown\n");
1790 			else
1791 				printk("%d%%\n", cx & 0xff);
1792 			if (apm_info.connection_version > 0x100) {
1793 				printk(KERN_INFO
1794 				       "apm: battery flag 0x%02x, battery life ",
1795 				       (cx >> 8) & 0xff);
1796 				if (dx == 0xffff)
1797 					printk("unknown\n");
1798 				else
1799 					printk("%d %s\n", dx & 0x7fff,
1800 					       (dx & 0x8000) ?
1801 					       "minutes" : "seconds");
1802 			}
1803 		}
1804 	}
1805 
1806 	/* Install our power off handler.. */
1807 	if (power_off)
1808 		pm_power_off = apm_power_off;
1809 
1810 	if (num_online_cpus() == 1 || smp) {
1811 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1812 		console_blank_hook = apm_console_blank;
1813 #endif
1814 		apm_mainloop();
1815 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1816 		console_blank_hook = NULL;
1817 #endif
1818 	}
1819 
1820 	return 0;
1821 }
1822 
1823 #ifndef MODULE
1824 static int __init apm_setup(char *str)
1825 {
1826 	int invert;
1827 
1828 	while ((str != NULL) && (*str != '\0')) {
1829 		if (strncmp(str, "off", 3) == 0)
1830 			apm_disabled = 1;
1831 		if (strncmp(str, "on", 2) == 0)
1832 			apm_disabled = 0;
1833 		if ((strncmp(str, "bounce-interval=", 16) == 0) ||
1834 		    (strncmp(str, "bounce_interval=", 16) == 0))
1835 			bounce_interval = simple_strtol(str + 16, NULL, 0);
1836 		if ((strncmp(str, "idle-threshold=", 15) == 0) ||
1837 		    (strncmp(str, "idle_threshold=", 15) == 0))
1838 			idle_threshold = simple_strtol(str + 15, NULL, 0);
1839 		if ((strncmp(str, "idle-period=", 12) == 0) ||
1840 		    (strncmp(str, "idle_period=", 12) == 0))
1841 			idle_period = simple_strtol(str + 12, NULL, 0);
1842 		invert = (strncmp(str, "no-", 3) == 0) ||
1843 			(strncmp(str, "no_", 3) == 0);
1844 		if (invert)
1845 			str += 3;
1846 		if (strncmp(str, "debug", 5) == 0)
1847 			debug = !invert;
1848 		if ((strncmp(str, "power-off", 9) == 0) ||
1849 		    (strncmp(str, "power_off", 9) == 0))
1850 			power_off = !invert;
1851 		if (strncmp(str, "smp", 3) == 0) {
1852 			smp = !invert;
1853 			idle_threshold = 100;
1854 		}
1855 		if ((strncmp(str, "allow-ints", 10) == 0) ||
1856 		    (strncmp(str, "allow_ints", 10) == 0))
1857 			apm_info.allow_ints = !invert;
1858 		if ((strncmp(str, "broken-psr", 10) == 0) ||
1859 		    (strncmp(str, "broken_psr", 10) == 0))
1860 			apm_info.get_power_status_broken = !invert;
1861 		if ((strncmp(str, "realmode-power-off", 18) == 0) ||
1862 		    (strncmp(str, "realmode_power_off", 18) == 0))
1863 			apm_info.realmode_power_off = !invert;
1864 		str = strchr(str, ',');
1865 		if (str != NULL)
1866 			str += strspn(str, ", \t");
1867 	}
1868 	return 1;
1869 }
1870 
1871 __setup("apm=", apm_setup);
1872 #endif
1873 
1874 static const struct file_operations apm_bios_fops = {
1875 	.owner		= THIS_MODULE,
1876 	.read		= do_read,
1877 	.poll		= do_poll,
1878 	.unlocked_ioctl	= do_ioctl,
1879 	.open		= do_open,
1880 	.release	= do_release,
1881 };
1882 
1883 static struct miscdevice apm_device = {
1884 	APM_MINOR_DEV,
1885 	"apm_bios",
1886 	&apm_bios_fops
1887 };
1888 
1889 
1890 /* Simple "print if true" callback */
1891 static int __init print_if_true(const struct dmi_system_id *d)
1892 {
1893 	printk("%s\n", d->ident);
1894 	return 0;
1895 }
1896 
1897 /*
1898  * Some Bioses enable the PS/2 mouse (touchpad) at resume, even if it was
1899  * disabled before the suspend. Linux used to get terribly confused by that.
1900  */
1901 static int __init broken_ps2_resume(const struct dmi_system_id *d)
1902 {
1903 	printk(KERN_INFO "%s machine detected. Mousepad Resume Bug "
1904 	       "workaround hopefully not needed.\n", d->ident);
1905 	return 0;
1906 }
1907 
1908 /* Some bioses have a broken protected mode poweroff and need to use realmode */
1909 static int __init set_realmode_power_off(const struct dmi_system_id *d)
1910 {
1911 	if (apm_info.realmode_power_off == 0) {
1912 		apm_info.realmode_power_off = 1;
1913 		printk(KERN_INFO "%s bios detected. "
1914 		       "Using realmode poweroff only.\n", d->ident);
1915 	}
1916 	return 0;
1917 }
1918 
1919 /* Some laptops require interrupts to be enabled during APM calls */
1920 static int __init set_apm_ints(const struct dmi_system_id *d)
1921 {
1922 	if (apm_info.allow_ints == 0) {
1923 		apm_info.allow_ints = 1;
1924 		printk(KERN_INFO "%s machine detected. "
1925 		       "Enabling interrupts during APM calls.\n", d->ident);
1926 	}
1927 	return 0;
1928 }
1929 
1930 /* Some APM bioses corrupt memory or just plain do not work */
1931 static int __init apm_is_horked(const struct dmi_system_id *d)
1932 {
1933 	if (apm_info.disabled == 0) {
1934 		apm_info.disabled = 1;
1935 		printk(KERN_INFO "%s machine detected. "
1936 		       "Disabling APM.\n", d->ident);
1937 	}
1938 	return 0;
1939 }
1940 
1941 static int __init apm_is_horked_d850md(const struct dmi_system_id *d)
1942 {
1943 	if (apm_info.disabled == 0) {
1944 		apm_info.disabled = 1;
1945 		printk(KERN_INFO "%s machine detected. "
1946 		       "Disabling APM.\n", d->ident);
1947 		printk(KERN_INFO "This bug is fixed in bios P15 which is available for \n");
1948 		printk(KERN_INFO "download from support.intel.com \n");
1949 	}
1950 	return 0;
1951 }
1952 
1953 /* Some APM bioses hang on APM idle calls */
1954 static int __init apm_likes_to_melt(const struct dmi_system_id *d)
1955 {
1956 	if (apm_info.forbid_idle == 0) {
1957 		apm_info.forbid_idle = 1;
1958 		printk(KERN_INFO "%s machine detected. "
1959 		       "Disabling APM idle calls.\n", d->ident);
1960 	}
1961 	return 0;
1962 }
1963 
1964 /*
1965  *  Check for clue free BIOS implementations who use
1966  *  the following QA technique
1967  *
1968  *      [ Write BIOS Code ]<------
1969  *               |                ^
1970  *      < Does it Compile >----N--
1971  *               |Y               ^
1972  *	< Does it Boot Win98 >-N--
1973  *               |Y
1974  *           [Ship It]
1975  *
1976  *	Phoenix A04  08/24/2000 is known bad (Dell Inspiron 5000e)
1977  *	Phoenix A07  09/29/2000 is known good (Dell Inspiron 5000)
1978  */
1979 static int __init broken_apm_power(const struct dmi_system_id *d)
1980 {
1981 	apm_info.get_power_status_broken = 1;
1982 	printk(KERN_WARNING "BIOS strings suggest APM bugs, "
1983 	       "disabling power status reporting.\n");
1984 	return 0;
1985 }
1986 
1987 /*
1988  * This bios swaps the APM minute reporting bytes over (Many sony laptops
1989  * have this problem).
1990  */
1991 static int __init swab_apm_power_in_minutes(const struct dmi_system_id *d)
1992 {
1993 	apm_info.get_power_status_swabinminutes = 1;
1994 	printk(KERN_WARNING "BIOS strings suggest APM reports battery life "
1995 	       "in minutes and wrong byte order.\n");
1996 	return 0;
1997 }
1998 
1999 static struct dmi_system_id __initdata apm_dmi_table[] = {
2000 	{
2001 		print_if_true,
2002 		KERN_WARNING "IBM T23 - BIOS 1.03b+ and controller firmware 1.02+ may be needed for Linux APM.",
2003 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
2004 			DMI_MATCH(DMI_BIOS_VERSION, "1AET38WW (1.01b)"), },
2005 	},
2006 	{	/* Handle problems with APM on the C600 */
2007 		broken_ps2_resume, "Dell Latitude C600",
2008 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
2009 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C600"), },
2010 	},
2011 	{	/* Allow interrupts during suspend on Dell Latitude laptops*/
2012 		set_apm_ints, "Dell Latitude",
2013 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2014 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C510"), }
2015 	},
2016 	{	/* APM crashes */
2017 		apm_is_horked, "Dell Inspiron 2500",
2018 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2019 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2020 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2021 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2022 	},
2023 	{	/* Allow interrupts during suspend on Dell Inspiron laptops*/
2024 		set_apm_ints, "Dell Inspiron", {
2025 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2026 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 4000"), },
2027 	},
2028 	{	/* Handle problems with APM on Inspiron 5000e */
2029 		broken_apm_power, "Dell Inspiron 5000e",
2030 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2031 			DMI_MATCH(DMI_BIOS_VERSION, "A04"),
2032 			DMI_MATCH(DMI_BIOS_DATE, "08/24/2000"), },
2033 	},
2034 	{	/* Handle problems with APM on Inspiron 2500 */
2035 		broken_apm_power, "Dell Inspiron 2500",
2036 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2037 			DMI_MATCH(DMI_BIOS_VERSION, "A12"),
2038 			DMI_MATCH(DMI_BIOS_DATE, "02/04/2002"), },
2039 	},
2040 	{	/* APM crashes */
2041 		apm_is_horked, "Dell Dimension 4100",
2042 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2043 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"),
2044 			DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2045 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2046 	},
2047 	{	/* Allow interrupts during suspend on Compaq Laptops*/
2048 		set_apm_ints, "Compaq 12XL125",
2049 		{	DMI_MATCH(DMI_SYS_VENDOR, "Compaq"),
2050 			DMI_MATCH(DMI_PRODUCT_NAME, "Compaq PC"),
2051 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2052 			DMI_MATCH(DMI_BIOS_VERSION, "4.06"), },
2053 	},
2054 	{	/* Allow interrupts during APM or the clock goes slow */
2055 		set_apm_ints, "ASUSTeK",
2056 		{	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
2057 			DMI_MATCH(DMI_PRODUCT_NAME, "L8400K series Notebook PC"), },
2058 	},
2059 	{	/* APM blows on shutdown */
2060 		apm_is_horked, "ABIT KX7-333[R]",
2061 		{	DMI_MATCH(DMI_BOARD_VENDOR, "ABIT"),
2062 			DMI_MATCH(DMI_BOARD_NAME, "VT8367-8233A (KX7-333[R])"), },
2063 	},
2064 	{	/* APM crashes */
2065 		apm_is_horked, "Trigem Delhi3",
2066 		{	DMI_MATCH(DMI_SYS_VENDOR, "TriGem Computer, Inc"),
2067 			DMI_MATCH(DMI_PRODUCT_NAME, "Delhi3"), },
2068 	},
2069 	{	/* APM crashes */
2070 		apm_is_horked, "Fujitsu-Siemens",
2071 		{	DMI_MATCH(DMI_BIOS_VENDOR, "hoenix/FUJITSU SIEMENS"),
2072 			DMI_MATCH(DMI_BIOS_VERSION, "Version1.01"), },
2073 	},
2074 	{	/* APM crashes */
2075 		apm_is_horked_d850md, "Intel D850MD",
2076 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2077 			DMI_MATCH(DMI_BIOS_VERSION, "MV85010A.86A.0016.P07.0201251536"), },
2078 	},
2079 	{	/* APM crashes */
2080 		apm_is_horked, "Intel D810EMO",
2081 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2082 			DMI_MATCH(DMI_BIOS_VERSION, "MO81010A.86A.0008.P04.0004170800"), },
2083 	},
2084 	{	/* APM crashes */
2085 		apm_is_horked, "Dell XPS-Z",
2086 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2087 			DMI_MATCH(DMI_BIOS_VERSION, "A11"),
2088 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"), },
2089 	},
2090 	{	/* APM crashes */
2091 		apm_is_horked, "Sharp PC-PJ/AX",
2092 		{	DMI_MATCH(DMI_SYS_VENDOR, "SHARP"),
2093 			DMI_MATCH(DMI_PRODUCT_NAME, "PC-PJ/AX"),
2094 			DMI_MATCH(DMI_BIOS_VENDOR, "SystemSoft"),
2095 			DMI_MATCH(DMI_BIOS_VERSION, "Version R2.08"), },
2096 	},
2097 	{	/* APM crashes */
2098 		apm_is_horked, "Dell Inspiron 2500",
2099 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2100 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2101 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2102 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2103 	},
2104 	{	/* APM idle hangs */
2105 		apm_likes_to_melt, "Jabil AMD",
2106 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2107 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP06"), },
2108 	},
2109 	{	/* APM idle hangs */
2110 		apm_likes_to_melt, "AMI Bios",
2111 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2112 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP05"), },
2113 	},
2114 	{	/* Handle problems with APM on Sony Vaio PCG-N505X(DE) */
2115 		swab_apm_power_in_minutes, "Sony VAIO",
2116 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2117 			DMI_MATCH(DMI_BIOS_VERSION, "R0206H"),
2118 			DMI_MATCH(DMI_BIOS_DATE, "08/23/99"), },
2119 	},
2120 	{	/* Handle problems with APM on Sony Vaio PCG-N505VX */
2121 		swab_apm_power_in_minutes, "Sony VAIO",
2122 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2123 			DMI_MATCH(DMI_BIOS_VERSION, "W2K06H0"),
2124 			DMI_MATCH(DMI_BIOS_DATE, "02/03/00"), },
2125 	},
2126 	{	/* Handle problems with APM on Sony Vaio PCG-XG29 */
2127 		swab_apm_power_in_minutes, "Sony VAIO",
2128 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2129 			DMI_MATCH(DMI_BIOS_VERSION, "R0117A0"),
2130 			DMI_MATCH(DMI_BIOS_DATE, "04/25/00"), },
2131 	},
2132 	{	/* Handle problems with APM on Sony Vaio PCG-Z600NE */
2133 		swab_apm_power_in_minutes, "Sony VAIO",
2134 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2135 			DMI_MATCH(DMI_BIOS_VERSION, "R0121Z1"),
2136 			DMI_MATCH(DMI_BIOS_DATE, "05/11/00"), },
2137 	},
2138 	{	/* Handle problems with APM on Sony Vaio PCG-Z600NE */
2139 		swab_apm_power_in_minutes, "Sony VAIO",
2140 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2141 			DMI_MATCH(DMI_BIOS_VERSION, "WME01Z1"),
2142 			DMI_MATCH(DMI_BIOS_DATE, "08/11/00"), },
2143 	},
2144 	{	/* Handle problems with APM on Sony Vaio PCG-Z600LEK(DE) */
2145 		swab_apm_power_in_minutes, "Sony VAIO",
2146 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2147 			DMI_MATCH(DMI_BIOS_VERSION, "R0206Z3"),
2148 			DMI_MATCH(DMI_BIOS_DATE, "12/25/00"), },
2149 	},
2150 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS */
2151 		swab_apm_power_in_minutes, "Sony VAIO",
2152 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2153 			DMI_MATCH(DMI_BIOS_VERSION, "R0203D0"),
2154 			DMI_MATCH(DMI_BIOS_DATE, "05/12/00"), },
2155 	},
2156 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS */
2157 		swab_apm_power_in_minutes, "Sony VAIO",
2158 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2159 			DMI_MATCH(DMI_BIOS_VERSION, "R0203Z3"),
2160 			DMI_MATCH(DMI_BIOS_DATE, "08/25/00"), },
2161 	},
2162 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS (with updated BIOS) */
2163 		swab_apm_power_in_minutes, "Sony VAIO",
2164 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2165 			DMI_MATCH(DMI_BIOS_VERSION, "R0209Z3"),
2166 			DMI_MATCH(DMI_BIOS_DATE, "05/12/01"), },
2167 	},
2168 	{	/* Handle problems with APM on Sony Vaio PCG-F104K */
2169 		swab_apm_power_in_minutes, "Sony VAIO",
2170 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2171 			DMI_MATCH(DMI_BIOS_VERSION, "R0204K2"),
2172 			DMI_MATCH(DMI_BIOS_DATE, "08/28/00"), },
2173 	},
2174 
2175 	{	/* Handle problems with APM on Sony Vaio PCG-C1VN/C1VE */
2176 		swab_apm_power_in_minutes, "Sony VAIO",
2177 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2178 			DMI_MATCH(DMI_BIOS_VERSION, "R0208P1"),
2179 			DMI_MATCH(DMI_BIOS_DATE, "11/09/00"), },
2180 	},
2181 	{	/* Handle problems with APM on Sony Vaio PCG-C1VE */
2182 		swab_apm_power_in_minutes, "Sony VAIO",
2183 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2184 			DMI_MATCH(DMI_BIOS_VERSION, "R0204P1"),
2185 			DMI_MATCH(DMI_BIOS_DATE, "09/12/00"), },
2186 	},
2187 	{	/* Handle problems with APM on Sony Vaio PCG-C1VE */
2188 		swab_apm_power_in_minutes, "Sony VAIO",
2189 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2190 			DMI_MATCH(DMI_BIOS_VERSION, "WXPO1Z3"),
2191 			DMI_MATCH(DMI_BIOS_DATE, "10/26/01"), },
2192 	},
2193 	{	/* broken PM poweroff bios */
2194 		set_realmode_power_off, "Award Software v4.60 PGMA",
2195 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Award Software International, Inc."),
2196 			DMI_MATCH(DMI_BIOS_VERSION, "4.60 PGMA"),
2197 			DMI_MATCH(DMI_BIOS_DATE, "134526184"), },
2198 	},
2199 
2200 	/* Generic per vendor APM settings  */
2201 
2202 	{	/* Allow interrupts during suspend on IBM laptops */
2203 		set_apm_ints, "IBM",
2204 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"), },
2205 	},
2206 
2207 	{ }
2208 };
2209 
2210 /*
2211  * Just start the APM thread. We do NOT want to do APM BIOS
2212  * calls from anything but the APM thread, if for no other reason
2213  * than the fact that we don't trust the APM BIOS. This way,
2214  * most common APM BIOS problems that lead to protection errors
2215  * etc will have at least some level of being contained...
2216  *
2217  * In short, if something bad happens, at least we have a choice
2218  * of just killing the apm thread..
2219  */
2220 static int __init apm_init(void)
2221 {
2222 	struct desc_struct *gdt;
2223 	int err;
2224 
2225 	dmi_check_system(apm_dmi_table);
2226 
2227 	if (apm_info.bios.version == 0 || paravirt_enabled() || machine_is_olpc()) {
2228 		printk(KERN_INFO "apm: BIOS not found.\n");
2229 		return -ENODEV;
2230 	}
2231 	printk(KERN_INFO
2232 	       "apm: BIOS version %d.%d Flags 0x%02x (Driver version %s)\n",
2233 	       ((apm_info.bios.version >> 8) & 0xff),
2234 	       (apm_info.bios.version & 0xff),
2235 	       apm_info.bios.flags,
2236 	       driver_version);
2237 	if ((apm_info.bios.flags & APM_32_BIT_SUPPORT) == 0) {
2238 		printk(KERN_INFO "apm: no 32 bit BIOS support\n");
2239 		return -ENODEV;
2240 	}
2241 
2242 	if (allow_ints)
2243 		apm_info.allow_ints = 1;
2244 	if (broken_psr)
2245 		apm_info.get_power_status_broken = 1;
2246 	if (realmode_power_off)
2247 		apm_info.realmode_power_off = 1;
2248 	/* User can override, but default is to trust DMI */
2249 	if (apm_disabled != -1)
2250 		apm_info.disabled = apm_disabled;
2251 
2252 	/*
2253 	 * Fix for the Compaq Contura 3/25c which reports BIOS version 0.1
2254 	 * but is reportedly a 1.0 BIOS.
2255 	 */
2256 	if (apm_info.bios.version == 0x001)
2257 		apm_info.bios.version = 0x100;
2258 
2259 	/* BIOS < 1.2 doesn't set cseg_16_len */
2260 	if (apm_info.bios.version < 0x102)
2261 		apm_info.bios.cseg_16_len = 0; /* 64k */
2262 
2263 	if (debug) {
2264 		printk(KERN_INFO "apm: entry %x:%x cseg16 %x dseg %x",
2265 			apm_info.bios.cseg, apm_info.bios.offset,
2266 			apm_info.bios.cseg_16, apm_info.bios.dseg);
2267 		if (apm_info.bios.version > 0x100)
2268 			printk(" cseg len %x, dseg len %x",
2269 				apm_info.bios.cseg_len,
2270 				apm_info.bios.dseg_len);
2271 		if (apm_info.bios.version > 0x101)
2272 			printk(" cseg16 len %x", apm_info.bios.cseg_16_len);
2273 		printk("\n");
2274 	}
2275 
2276 	if (apm_info.disabled) {
2277 		printk(KERN_NOTICE "apm: disabled on user request.\n");
2278 		return -ENODEV;
2279 	}
2280 	if ((num_online_cpus() > 1) && !power_off && !smp) {
2281 		printk(KERN_NOTICE "apm: disabled - APM is not SMP safe.\n");
2282 		apm_info.disabled = 1;
2283 		return -ENODEV;
2284 	}
2285 	if (pm_flags & PM_ACPI) {
2286 		printk(KERN_NOTICE "apm: overridden by ACPI.\n");
2287 		apm_info.disabled = 1;
2288 		return -ENODEV;
2289 	}
2290 	pm_flags |= PM_APM;
2291 
2292 	/*
2293 	 * Set up a segment that references the real mode segment 0x40
2294 	 * that extends up to the end of page zero (that we have reserved).
2295 	 * This is for buggy BIOS's that refer to (real mode) segment 0x40
2296 	 * even though they are called in protected mode.
2297 	 */
2298 	set_base(bad_bios_desc, __va((unsigned long)0x40 << 4));
2299 	_set_limit((char *)&bad_bios_desc, 4095 - (0x40 << 4));
2300 
2301 	/*
2302 	 * Set up the long jump entry point to the APM BIOS, which is called
2303 	 * from inline assembly.
2304 	 */
2305 	apm_bios_entry.offset = apm_info.bios.offset;
2306 	apm_bios_entry.segment = APM_CS;
2307 
2308 	/*
2309 	 * The APM 1.1 BIOS is supposed to provide limit information that it
2310 	 * recognizes.  Many machines do this correctly, but many others do
2311 	 * not restrict themselves to their claimed limit.  When this happens,
2312 	 * they will cause a segmentation violation in the kernel at boot time.
2313 	 * Most BIOS's, however, will respect a 64k limit, so we use that.
2314 	 *
2315 	 * Note we only set APM segments on CPU zero, since we pin the APM
2316 	 * code to that CPU.
2317 	 */
2318 	gdt = get_cpu_gdt_table(0);
2319 	set_base(gdt[APM_CS >> 3],
2320 		 __va((unsigned long)apm_info.bios.cseg << 4));
2321 	set_base(gdt[APM_CS_16 >> 3],
2322 		 __va((unsigned long)apm_info.bios.cseg_16 << 4));
2323 	set_base(gdt[APM_DS >> 3],
2324 		 __va((unsigned long)apm_info.bios.dseg << 4));
2325 
2326 	proc_create("apm", 0, NULL, &apm_file_ops);
2327 
2328 	kapmd_task = kthread_create(apm, NULL, "kapmd");
2329 	if (IS_ERR(kapmd_task)) {
2330 		printk(KERN_ERR "apm: disabled - Unable to start kernel "
2331 				"thread.\n");
2332 		err = PTR_ERR(kapmd_task);
2333 		kapmd_task = NULL;
2334 		remove_proc_entry("apm", NULL);
2335 		return err;
2336 	}
2337 	wake_up_process(kapmd_task);
2338 
2339 	if (num_online_cpus() > 1 && !smp) {
2340 		printk(KERN_NOTICE
2341 		       "apm: disabled - APM is not SMP safe (power off active).\n");
2342 		return 0;
2343 	}
2344 
2345 	/*
2346 	 * Note we don't actually care if the misc_device cannot be registered.
2347 	 * this driver can do its job without it, even if userspace can't
2348 	 * control it.  just log the error
2349 	 */
2350 	if (misc_register(&apm_device))
2351 		printk(KERN_WARNING "apm: Could not register misc device.\n");
2352 
2353 	if (HZ != 100)
2354 		idle_period = (idle_period * HZ) / 100;
2355 	if (idle_threshold < 100) {
2356 		original_pm_idle = pm_idle;
2357 		pm_idle  = apm_cpu_idle;
2358 		set_pm_idle = 1;
2359 	}
2360 
2361 	return 0;
2362 }
2363 
2364 static void __exit apm_exit(void)
2365 {
2366 	int error;
2367 
2368 	if (set_pm_idle) {
2369 		pm_idle = original_pm_idle;
2370 		/*
2371 		 * We are about to unload the current idle thread pm callback
2372 		 * (pm_idle), Wait for all processors to update cached/local
2373 		 * copies of pm_idle before proceeding.
2374 		 */
2375 		cpu_idle_wait();
2376 	}
2377 	if (((apm_info.bios.flags & APM_BIOS_DISENGAGED) == 0)
2378 	    && (apm_info.connection_version > 0x0100)) {
2379 		error = apm_engage_power_management(APM_DEVICE_ALL, 0);
2380 		if (error)
2381 			apm_error("disengage power management", error);
2382 	}
2383 	misc_deregister(&apm_device);
2384 	remove_proc_entry("apm", NULL);
2385 	if (power_off)
2386 		pm_power_off = NULL;
2387 	if (kapmd_task) {
2388 		kthread_stop(kapmd_task);
2389 		kapmd_task = NULL;
2390 	}
2391 	pm_flags &= ~PM_APM;
2392 }
2393 
2394 module_init(apm_init);
2395 module_exit(apm_exit);
2396 
2397 MODULE_AUTHOR("Stephen Rothwell");
2398 MODULE_DESCRIPTION("Advanced Power Management");
2399 MODULE_LICENSE("GPL");
2400 module_param(debug, bool, 0644);
2401 MODULE_PARM_DESC(debug, "Enable debug mode");
2402 module_param(power_off, bool, 0444);
2403 MODULE_PARM_DESC(power_off, "Enable power off");
2404 module_param(bounce_interval, int, 0444);
2405 MODULE_PARM_DESC(bounce_interval,
2406 		"Set the number of ticks to ignore suspend bounces");
2407 module_param(allow_ints, bool, 0444);
2408 MODULE_PARM_DESC(allow_ints, "Allow interrupts during BIOS calls");
2409 module_param(broken_psr, bool, 0444);
2410 MODULE_PARM_DESC(broken_psr, "BIOS has a broken GetPowerStatus call");
2411 module_param(realmode_power_off, bool, 0444);
2412 MODULE_PARM_DESC(realmode_power_off,
2413 		"Switch to real mode before powering off");
2414 module_param(idle_threshold, int, 0444);
2415 MODULE_PARM_DESC(idle_threshold,
2416 	"System idle percentage above which to make APM BIOS idle calls");
2417 module_param(idle_period, int, 0444);
2418 MODULE_PARM_DESC(idle_period,
2419 	"Period (in sec/100) over which to caculate the idle percentage");
2420 module_param(smp, bool, 0444);
2421 MODULE_PARM_DESC(smp,
2422 	"Set this to enable APM use on an SMP platform. Use with caution on older systems");
2423 MODULE_ALIAS_MISCDEV(APM_MINOR_DEV);
2424