xref: /openbmc/linux/arch/x86/kernel/apm_32.c (revision 6db6b729)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* -*- linux-c -*-
3  * APM BIOS driver for Linux
4  * Copyright 1994-2001 Stephen Rothwell (sfr@canb.auug.org.au)
5  *
6  * Initial development of this driver was funded by NEC Australia P/L
7  *	and NEC Corporation
8  *
9  * October 1995, Rik Faith (faith@cs.unc.edu):
10  *    Minor enhancements and updates (to the patch set) for 1.3.x
11  *    Documentation
12  * January 1996, Rik Faith (faith@cs.unc.edu):
13  *    Make /proc/apm easy to format (bump driver version)
14  * March 1996, Rik Faith (faith@cs.unc.edu):
15  *    Prohibit APM BIOS calls unless apm_enabled.
16  *    (Thanks to Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>)
17  * April 1996, Stephen Rothwell (sfr@canb.auug.org.au)
18  *    Version 1.0 and 1.1
19  * May 1996, Version 1.2
20  * Feb 1998, Version 1.3
21  * Feb 1998, Version 1.4
22  * Aug 1998, Version 1.5
23  * Sep 1998, Version 1.6
24  * Nov 1998, Version 1.7
25  * Jan 1999, Version 1.8
26  * Jan 1999, Version 1.9
27  * Oct 1999, Version 1.10
28  * Nov 1999, Version 1.11
29  * Jan 2000, Version 1.12
30  * Feb 2000, Version 1.13
31  * Nov 2000, Version 1.14
32  * Oct 2001, Version 1.15
33  * Jan 2002, Version 1.16
34  * Oct 2002, Version 1.16ac
35  *
36  * History:
37  *    0.6b: first version in official kernel, Linux 1.3.46
38  *    0.7: changed /proc/apm format, Linux 1.3.58
39  *    0.8: fixed gcc 2.7.[12] compilation problems, Linux 1.3.59
40  *    0.9: only call bios if bios is present, Linux 1.3.72
41  *    1.0: use fixed device number, consolidate /proc/apm into this file,
42  *         Linux 1.3.85
43  *    1.1: support user-space standby and suspend, power off after system
44  *         halted, Linux 1.3.98
45  *    1.2: When resetting RTC after resume, take care so that the time
46  *         is only incorrect by 30-60mS (vs. 1S previously) (Gabor J. Toth
47  *         <jtoth@princeton.edu>); improve interaction between
48  *         screen-blanking and gpm (Stephen Rothwell); Linux 1.99.4
49  *    1.2a:Simple change to stop mysterious bug reports with SMP also added
50  *	   levels to the printk calls. APM is not defined for SMP machines.
51  *         The new replacement for it is, but Linux doesn't yet support this.
52  *         Alan Cox Linux 2.1.55
53  *    1.3: Set up a valid data descriptor 0x40 for buggy BIOS's
54  *    1.4: Upgraded to support APM 1.2. Integrated ThinkPad suspend patch by
55  *         Dean Gaudet <dgaudet@arctic.org>.
56  *         C. Scott Ananian <cananian@alumni.princeton.edu> Linux 2.1.87
57  *    1.5: Fix segment register reloading (in case of bad segments saved
58  *         across BIOS call).
59  *         Stephen Rothwell
60  *    1.6: Cope with compiler/assembler differences.
61  *         Only try to turn off the first display device.
62  *         Fix OOPS at power off with no APM BIOS by Jan Echternach
63  *                   <echter@informatik.uni-rostock.de>
64  *         Stephen Rothwell
65  *    1.7: Modify driver's cached copy of the disabled/disengaged flags
66  *         to reflect current state of APM BIOS.
67  *         Chris Rankin <rankinc@bellsouth.net>
68  *         Reset interrupt 0 timer to 100Hz after suspend
69  *         Chad Miller <cmiller@surfsouth.com>
70  *         Add CONFIG_APM_IGNORE_SUSPEND_BOUNCE
71  *         Richard Gooch <rgooch@atnf.csiro.au>
72  *         Allow boot time disabling of APM
73  *         Make boot messages far less verbose by default
74  *         Make asm safer
75  *         Stephen Rothwell
76  *    1.8: Add CONFIG_APM_RTC_IS_GMT
77  *         Richard Gooch <rgooch@atnf.csiro.au>
78  *         change APM_NOINTS to CONFIG_APM_ALLOW_INTS
79  *         remove dependency on CONFIG_PROC_FS
80  *         Stephen Rothwell
81  *    1.9: Fix small typo.  <laslo@wodip.opole.pl>
82  *         Try to cope with BIOS's that need to have all display
83  *         devices blanked and not just the first one.
84  *         Ross Paterson <ross@soi.city.ac.uk>
85  *         Fix segment limit setting it has always been wrong as
86  *         the segments needed to have byte granularity.
87  *         Mark a few things __init.
88  *         Add hack to allow power off of SMP systems by popular request.
89  *         Use CONFIG_SMP instead of __SMP__
90  *         Ignore BOUNCES for three seconds.
91  *         Stephen Rothwell
92  *   1.10: Fix for Thinkpad return code.
93  *         Merge 2.2 and 2.3 drivers.
94  *         Remove APM dependencies in arch/i386/kernel/process.c
95  *         Remove APM dependencies in drivers/char/sysrq.c
96  *         Reset time across standby.
97  *         Allow more initialisation on SMP.
98  *         Remove CONFIG_APM_POWER_OFF and make it boot time
99  *         configurable (default on).
100  *         Make debug only a boot time parameter (remove APM_DEBUG).
101  *         Try to blank all devices on any error.
102  *   1.11: Remove APM dependencies in drivers/char/console.c
103  *         Check nr_running to detect if we are idle (from
104  *         Borislav Deianov <borislav@lix.polytechnique.fr>)
105  *         Fix for bioses that don't zero the top part of the
106  *         entrypoint offset (Mario Sitta <sitta@al.unipmn.it>)
107  *         (reported by Panos Katsaloulis <teras@writeme.com>).
108  *         Real mode power off patch (Walter Hofmann
109  *         <Walter.Hofmann@physik.stud.uni-erlangen.de>).
110  *   1.12: Remove CONFIG_SMP as the compiler will optimize
111  *         the code away anyway (smp_num_cpus == 1 in UP)
112  *         noted by Artur Skawina <skawina@geocities.com>.
113  *         Make power off under SMP work again.
114  *         Fix thinko with initial engaging of BIOS.
115  *         Make sure power off only happens on CPU 0
116  *         (Paul "Rusty" Russell <rusty@rustcorp.com.au>).
117  *         Do error notification to user mode if BIOS calls fail.
118  *         Move entrypoint offset fix to ...boot/setup.S
119  *         where it belongs (Cosmos <gis88564@cis.nctu.edu.tw>).
120  *         Remove smp-power-off. SMP users must now specify
121  *         "apm=power-off" on the kernel command line. Suggested
122  *         by Jim Avera <jima@hal.com>, modified by Alan Cox
123  *         <alan@lxorguk.ukuu.org.uk>.
124  *         Register the /proc/apm entry even on SMP so that
125  *         scripts that check for it before doing power off
126  *         work (Jim Avera <jima@hal.com>).
127  *   1.13: Changes for new pm_ interfaces (Andy Henroid
128  *         <andy_henroid@yahoo.com>).
129  *         Modularize the code.
130  *         Fix the Thinkpad (again) :-( (CONFIG_APM_IGNORE_MULTIPLE_SUSPENDS
131  *         is now the way life works).
132  *         Fix thinko in suspend() (wrong return).
133  *         Notify drivers on critical suspend.
134  *         Make kapmd absorb more idle time (Pavel Machek <pavel@ucw.cz>
135  *         modified by sfr).
136  *         Disable interrupts while we are suspended (Andy Henroid
137  *         <andy_henroid@yahoo.com> fixed by sfr).
138  *         Make power off work on SMP again (Tony Hoyle
139  *         <tmh@magenta-logic.com> and <zlatko@iskon.hr>) modified by sfr.
140  *         Remove CONFIG_APM_SUSPEND_BOUNCE.  The bounce ignore
141  *         interval is now configurable.
142  *   1.14: Make connection version persist across module unload/load.
143  *         Enable and engage power management earlier.
144  *         Disengage power management on module unload.
145  *         Changed to use the sysrq-register hack for registering the
146  *         power off function called by magic sysrq based upon discussions
147  *         in irc://irc.openprojects.net/#kernelnewbies
148  *         (Crutcher Dunnavant <crutcher+kernel@datastacks.com>).
149  *         Make CONFIG_APM_REAL_MODE_POWER_OFF run time configurable.
150  *         (Arjan van de Ven <arjanv@redhat.com>) modified by sfr.
151  *         Work around byte swap bug in one of the Vaio's BIOS's
152  *         (Marc Boucher <marc@mbsi.ca>).
153  *         Exposed the disable flag to dmi so that we can handle known
154  *         broken APM (Alan Cox <alan@lxorguk.ukuu.org.uk>).
155  *   1.14ac: If the BIOS says "I slowed the CPU down" then don't spin
156  *         calling it - instead idle. (Alan Cox <alan@lxorguk.ukuu.org.uk>)
157  *         If an APM idle fails log it and idle sensibly
158  *   1.15: Don't queue events to clients who open the device O_WRONLY.
159  *         Don't expect replies from clients who open the device O_RDONLY.
160  *         (Idea from Thomas Hood)
161  *         Minor waitqueue cleanups. (John Fremlin <chief@bandits.org>)
162  *   1.16: Fix idle calling. (Andreas Steinmetz <ast@domdv.de> et al.)
163  *         Notify listeners of standby or suspend events before notifying
164  *         drivers. Return EBUSY to ioctl() if suspend is rejected.
165  *         (Russell King <rmk@arm.linux.org.uk> and Thomas Hood)
166  *         Ignore first resume after we generate our own resume event
167  *         after a suspend (Thomas Hood)
168  *         Daemonize now gets rid of our controlling terminal (sfr).
169  *         CONFIG_APM_CPU_IDLE now just affects the default value of
170  *         idle_threshold (sfr).
171  *         Change name of kernel apm daemon (as it no longer idles) (sfr).
172  *   1.16ac: Fix up SMP support somewhat. You can now force SMP on and we
173  *	   make _all_ APM calls on the CPU#0. Fix unsafe sign bug.
174  *	   TODO: determine if its "boot CPU" or "CPU0" we want to lock to.
175  *
176  * APM 1.1 Reference:
177  *
178  *   Intel Corporation, Microsoft Corporation. Advanced Power Management
179  *   (APM) BIOS Interface Specification, Revision 1.1, September 1993.
180  *   Intel Order Number 241704-001.  Microsoft Part Number 781-110-X01.
181  *
182  * [This document is available free from Intel by calling 800.628.8686 (fax
183  * 916.356.6100) or 800.548.4725; or from
184  * http://www.microsoft.com/whdc/archive/amp_12.mspx  It is also
185  * available from Microsoft by calling 206.882.8080.]
186  *
187  * APM 1.2 Reference:
188  *   Intel Corporation, Microsoft Corporation. Advanced Power Management
189  *   (APM) BIOS Interface Specification, Revision 1.2, February 1996.
190  *
191  * [This document is available from Microsoft at:
192  *    http://www.microsoft.com/whdc/archive/amp_12.mspx]
193  */
194 
195 #define pr_fmt(fmt) "apm: " fmt
196 
197 #include <linux/module.h>
198 
199 #include <linux/poll.h>
200 #include <linux/types.h>
201 #include <linux/stddef.h>
202 #include <linux/timer.h>
203 #include <linux/fcntl.h>
204 #include <linux/slab.h>
205 #include <linux/stat.h>
206 #include <linux/proc_fs.h>
207 #include <linux/seq_file.h>
208 #include <linux/miscdevice.h>
209 #include <linux/apm_bios.h>
210 #include <linux/init.h>
211 #include <linux/time.h>
212 #include <linux/sched/signal.h>
213 #include <linux/sched/cputime.h>
214 #include <linux/pm.h>
215 #include <linux/capability.h>
216 #include <linux/device.h>
217 #include <linux/kernel.h>
218 #include <linux/freezer.h>
219 #include <linux/smp.h>
220 #include <linux/dmi.h>
221 #include <linux/suspend.h>
222 #include <linux/kthread.h>
223 #include <linux/jiffies.h>
224 #include <linux/acpi.h>
225 #include <linux/syscore_ops.h>
226 #include <linux/i8253.h>
227 #include <linux/cpuidle.h>
228 
229 #include <linux/uaccess.h>
230 #include <asm/desc.h>
231 #include <asm/olpc.h>
232 #include <asm/paravirt.h>
233 #include <asm/reboot.h>
234 #include <asm/nospec-branch.h>
235 #include <asm/ibt.h>
236 
237 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
238 extern int (*console_blank_hook)(int);
239 #endif
240 
241 /*
242  * Various options can be changed at boot time as follows:
243  * (We allow underscores for compatibility with the modules code)
244  *	apm=on/off			enable/disable APM
245  *	    [no-]allow[-_]ints		allow interrupts during BIOS calls
246  *	    [no-]broken[-_]psr		BIOS has a broken GetPowerStatus call
247  *	    [no-]realmode[-_]power[-_]off	switch to real mode before
248  *	    					powering off
249  *	    [no-]debug			log some debugging messages
250  *	    [no-]power[-_]off		power off on shutdown
251  *	    [no-]smp			Use apm even on an SMP box
252  *	    bounce[-_]interval=<n>	number of ticks to ignore suspend
253  *	    				bounces
254  *          idle[-_]threshold=<n>       System idle percentage above which to
255  *                                      make APM BIOS idle calls. Set it to
256  *                                      100 to disable.
257  *          idle[-_]period=<n>          Period (in 1/100s of a second) over
258  *                                      which the idle percentage is
259  *                                      calculated.
260  */
261 
262 /* KNOWN PROBLEM MACHINES:
263  *
264  * U: TI 4000M TravelMate: BIOS is *NOT* APM compliant
265  *                         [Confirmed by TI representative]
266  * ?: ACER 486DX4/75: uses dseg 0040, in violation of APM specification
267  *                    [Confirmed by BIOS disassembly]
268  *                    [This may work now ...]
269  * P: Toshiba 1950S: battery life information only gets updated after resume
270  * P: Midwest Micro Soundbook Elite DX2/66 monochrome: screen blanking
271  * 	broken in BIOS [Reported by Garst R. Reese <reese@isn.net>]
272  * ?: AcerNote-950: oops on reading /proc/apm - workaround is a WIP
273  * 	Neale Banks <neale@lowendale.com.au> December 2000
274  *
275  * Legend: U = unusable with APM patches
276  *         P = partially usable with APM patches
277  */
278 
279 /*
280  * Define as 1 to make the driver always call the APM BIOS busy
281  * routine even if the clock was not reported as slowed by the
282  * idle routine.  Otherwise, define as 0.
283  */
284 #define ALWAYS_CALL_BUSY   1
285 
286 /*
287  * Define to make the APM BIOS calls zero all data segment registers (so
288  * that an incorrect BIOS implementation will cause a kernel panic if it
289  * tries to write to arbitrary memory).
290  */
291 #define APM_ZERO_SEGS
292 
293 #include <asm/apm.h>
294 
295 /*
296  * Define to re-initialize the interrupt 0 timer to 100 Hz after a suspend.
297  * This patched by Chad Miller <cmiller@surfsouth.com>, original code by
298  * David Chen <chen@ctpa04.mit.edu>
299  */
300 #undef INIT_TIMER_AFTER_SUSPEND
301 
302 #ifdef INIT_TIMER_AFTER_SUSPEND
303 #include <linux/timex.h>
304 #include <asm/io.h>
305 #include <linux/delay.h>
306 #endif
307 
308 /*
309  * Need to poll the APM BIOS every second
310  */
311 #define APM_CHECK_TIMEOUT	(HZ)
312 
313 /*
314  * Ignore suspend events for this amount of time after a resume
315  */
316 #define DEFAULT_BOUNCE_INTERVAL	(3 * HZ)
317 
318 /*
319  * Maximum number of events stored
320  */
321 #define APM_MAX_EVENTS		20
322 
323 /*
324  * The per-file APM data
325  */
326 struct apm_user {
327 	int		magic;
328 	struct apm_user *next;
329 	unsigned int	suser: 1;
330 	unsigned int	writer: 1;
331 	unsigned int	reader: 1;
332 	unsigned int	suspend_wait: 1;
333 	int		suspend_result;
334 	int		suspends_pending;
335 	int		standbys_pending;
336 	int		suspends_read;
337 	int		standbys_read;
338 	int		event_head;
339 	int		event_tail;
340 	apm_event_t	events[APM_MAX_EVENTS];
341 };
342 
343 /*
344  * The magic number in apm_user
345  */
346 #define APM_BIOS_MAGIC		0x4101
347 
348 /*
349  * idle percentage above which bios idle calls are done
350  */
351 #ifdef CONFIG_APM_CPU_IDLE
352 #define DEFAULT_IDLE_THRESHOLD	95
353 #else
354 #define DEFAULT_IDLE_THRESHOLD	100
355 #endif
356 #define DEFAULT_IDLE_PERIOD	(100 / 3)
357 
358 static int apm_cpu_idle(struct cpuidle_device *dev,
359 			struct cpuidle_driver *drv, int index);
360 
361 static struct cpuidle_driver apm_idle_driver = {
362 	.name = "apm_idle",
363 	.owner = THIS_MODULE,
364 	.states = {
365 		{ /* entry 0 is for polling */ },
366 		{ /* entry 1 is for APM idle */
367 			.name = "APM",
368 			.desc = "APM idle",
369 			.exit_latency = 250,	/* WAG */
370 			.target_residency = 500,	/* WAG */
371 			.enter = &apm_cpu_idle
372 		},
373 	},
374 	.state_count = 2,
375 };
376 
377 static struct cpuidle_device apm_cpuidle_device;
378 
379 /*
380  * Local variables
381  */
382 __visible struct {
383 	unsigned long	offset;
384 	unsigned short	segment;
385 } apm_bios_entry;
386 static int clock_slowed;
387 static int idle_threshold __read_mostly = DEFAULT_IDLE_THRESHOLD;
388 static int idle_period __read_mostly = DEFAULT_IDLE_PERIOD;
389 static int suspends_pending;
390 static int standbys_pending;
391 static int ignore_sys_suspend;
392 static int ignore_normal_resume;
393 static int bounce_interval __read_mostly = DEFAULT_BOUNCE_INTERVAL;
394 
395 static bool debug __read_mostly;
396 static bool smp __read_mostly;
397 static int apm_disabled = -1;
398 #ifdef CONFIG_SMP
399 static bool power_off;
400 #else
401 static bool power_off = 1;
402 #endif
403 static bool realmode_power_off;
404 #ifdef CONFIG_APM_ALLOW_INTS
405 static bool allow_ints = 1;
406 #else
407 static bool allow_ints;
408 #endif
409 static bool broken_psr;
410 
411 static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
412 static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
413 static struct apm_user *user_list;
414 static DEFINE_SPINLOCK(user_list_lock);
415 static DEFINE_MUTEX(apm_mutex);
416 
417 /*
418  * Set up a segment that references the real mode segment 0x40
419  * that extends up to the end of page zero (that we have reserved).
420  * This is for buggy BIOS's that refer to (real mode) segment 0x40
421  * even though they are called in protected mode.
422  */
423 static struct desc_struct bad_bios_desc = GDT_ENTRY_INIT(0x4092,
424 			(unsigned long)__va(0x400UL), PAGE_SIZE - 0x400 - 1);
425 
426 static const char driver_version[] = "1.16ac";	/* no spaces */
427 
428 static struct task_struct *kapmd_task;
429 
430 /*
431  *	APM event names taken from the APM 1.2 specification. These are
432  *	the message codes that the BIOS uses to tell us about events
433  */
434 static const char * const apm_event_name[] = {
435 	"system standby",
436 	"system suspend",
437 	"normal resume",
438 	"critical resume",
439 	"low battery",
440 	"power status change",
441 	"update time",
442 	"critical suspend",
443 	"user standby",
444 	"user suspend",
445 	"system standby resume",
446 	"capabilities change"
447 };
448 #define NR_APM_EVENT_NAME ARRAY_SIZE(apm_event_name)
449 
450 typedef struct lookup_t {
451 	int	key;
452 	char 	*msg;
453 } lookup_t;
454 
455 /*
456  *	The BIOS returns a set of standard error codes in AX when the
457  *	carry flag is set.
458  */
459 
460 static const lookup_t error_table[] = {
461 /* N/A	{ APM_SUCCESS,		"Operation succeeded" }, */
462 	{ APM_DISABLED,		"Power management disabled" },
463 	{ APM_CONNECTED,	"Real mode interface already connected" },
464 	{ APM_NOT_CONNECTED,	"Interface not connected" },
465 	{ APM_16_CONNECTED,	"16 bit interface already connected" },
466 /* N/A	{ APM_16_UNSUPPORTED,	"16 bit interface not supported" }, */
467 	{ APM_32_CONNECTED,	"32 bit interface already connected" },
468 	{ APM_32_UNSUPPORTED,	"32 bit interface not supported" },
469 	{ APM_BAD_DEVICE,	"Unrecognized device ID" },
470 	{ APM_BAD_PARAM,	"Parameter out of range" },
471 	{ APM_NOT_ENGAGED,	"Interface not engaged" },
472 	{ APM_BAD_FUNCTION,     "Function not supported" },
473 	{ APM_RESUME_DISABLED,	"Resume timer disabled" },
474 	{ APM_BAD_STATE,	"Unable to enter requested state" },
475 /* N/A	{ APM_NO_EVENTS,	"No events pending" }, */
476 	{ APM_NO_ERROR,		"BIOS did not set a return code" },
477 	{ APM_NOT_PRESENT,	"No APM present" }
478 };
479 #define ERROR_COUNT	ARRAY_SIZE(error_table)
480 
481 /**
482  *	apm_error	-	display an APM error
483  *	@str: information string
484  *	@err: APM BIOS return code
485  *
486  *	Write a meaningful log entry to the kernel log in the event of
487  *	an APM error.  Note that this also handles (negative) kernel errors.
488  */
489 
490 static void apm_error(char *str, int err)
491 {
492 	int i;
493 
494 	for (i = 0; i < ERROR_COUNT; i++)
495 		if (error_table[i].key == err)
496 			break;
497 	if (i < ERROR_COUNT)
498 		pr_notice("%s: %s\n", str, error_table[i].msg);
499 	else if (err < 0)
500 		pr_notice("%s: linux error code %i\n", str, err);
501 	else
502 		pr_notice("%s: unknown error code %#2.2x\n",
503 		       str, err);
504 }
505 
506 /*
507  * These are the actual BIOS calls.  Depending on APM_ZERO_SEGS and
508  * apm_info.allow_ints, we are being really paranoid here!  Not only
509  * are interrupts disabled, but all the segment registers (except SS)
510  * are saved and zeroed this means that if the BIOS tries to reference
511  * any data without explicitly loading the segment registers, the kernel
512  * will fault immediately rather than have some unforeseen circumstances
513  * for the rest of the kernel.  And it will be very obvious!  :-) Doing
514  * this depends on CS referring to the same physical memory as DS so that
515  * DS can be zeroed before the call. Unfortunately, we can't do anything
516  * about the stack segment/pointer.  Also, we tell the compiler that
517  * everything could change.
518  *
519  * Also, we KNOW that for the non error case of apm_bios_call, there
520  * is no useful data returned in the low order 8 bits of eax.
521  */
522 
523 static inline unsigned long __apm_irq_save(void)
524 {
525 	unsigned long flags;
526 	local_save_flags(flags);
527 	if (apm_info.allow_ints) {
528 		if (irqs_disabled_flags(flags))
529 			local_irq_enable();
530 	} else
531 		local_irq_disable();
532 
533 	return flags;
534 }
535 
536 #define apm_irq_save(flags) \
537 	do { flags = __apm_irq_save(); } while (0)
538 
539 static inline void apm_irq_restore(unsigned long flags)
540 {
541 	if (irqs_disabled_flags(flags))
542 		local_irq_disable();
543 	else if (irqs_disabled())
544 		local_irq_enable();
545 }
546 
547 #ifdef APM_ZERO_SEGS
548 #	define APM_DECL_SEGS \
549 		unsigned int saved_fs; unsigned int saved_gs;
550 #	define APM_DO_SAVE_SEGS \
551 		savesegment(fs, saved_fs); savesegment(gs, saved_gs)
552 #	define APM_DO_RESTORE_SEGS \
553 		loadsegment(fs, saved_fs); loadsegment(gs, saved_gs)
554 #else
555 #	define APM_DECL_SEGS
556 #	define APM_DO_SAVE_SEGS
557 #	define APM_DO_RESTORE_SEGS
558 #endif
559 
560 struct apm_bios_call {
561 	u32 func;
562 	/* In and out */
563 	u32 ebx;
564 	u32 ecx;
565 	/* Out only */
566 	u32 eax;
567 	u32 edx;
568 	u32 esi;
569 
570 	/* Error: -ENOMEM, or bits 8-15 of eax */
571 	int err;
572 };
573 
574 /**
575  *	__apm_bios_call - Make an APM BIOS 32bit call
576  *	@_call: pointer to struct apm_bios_call.
577  *
578  *	Make an APM call using the 32bit protected mode interface. The
579  *	caller is responsible for knowing if APM BIOS is configured and
580  *	enabled. This call can disable interrupts for a long period of
581  *	time on some laptops.  The return value is in AH and the carry
582  *	flag is loaded into AL.  If there is an error, then the error
583  *	code is returned in AH (bits 8-15 of eax) and this function
584  *	returns non-zero.
585  *
586  *	Note: this makes the call on the current CPU.
587  */
588 static long __apm_bios_call(void *_call)
589 {
590 	APM_DECL_SEGS
591 	unsigned long		flags;
592 	int			cpu;
593 	struct desc_struct	save_desc_40;
594 	struct desc_struct	*gdt;
595 	struct apm_bios_call	*call = _call;
596 	u64			ibt;
597 
598 	cpu = get_cpu();
599 	BUG_ON(cpu != 0);
600 	gdt = get_cpu_gdt_rw(cpu);
601 	save_desc_40 = gdt[0x40 / 8];
602 	gdt[0x40 / 8] = bad_bios_desc;
603 
604 	apm_irq_save(flags);
605 	firmware_restrict_branch_speculation_start();
606 	ibt = ibt_save(true);
607 	APM_DO_SAVE_SEGS;
608 	apm_bios_call_asm(call->func, call->ebx, call->ecx,
609 			  &call->eax, &call->ebx, &call->ecx, &call->edx,
610 			  &call->esi);
611 	APM_DO_RESTORE_SEGS;
612 	ibt_restore(ibt);
613 	firmware_restrict_branch_speculation_end();
614 	apm_irq_restore(flags);
615 	gdt[0x40 / 8] = save_desc_40;
616 	put_cpu();
617 
618 	return call->eax & 0xff;
619 }
620 
621 /* Run __apm_bios_call or __apm_bios_call_simple on CPU 0 */
622 static int on_cpu0(long (*fn)(void *), struct apm_bios_call *call)
623 {
624 	int ret;
625 
626 	/* Don't bother with work_on_cpu in the common case, so we don't
627 	 * have to worry about OOM or overhead. */
628 	if (get_cpu() == 0) {
629 		ret = fn(call);
630 		put_cpu();
631 	} else {
632 		put_cpu();
633 		ret = work_on_cpu(0, fn, call);
634 	}
635 
636 	/* work_on_cpu can fail with -ENOMEM */
637 	if (ret < 0)
638 		call->err = ret;
639 	else
640 		call->err = (call->eax >> 8) & 0xff;
641 
642 	return ret;
643 }
644 
645 /**
646  *	apm_bios_call	-	Make an APM BIOS 32bit call (on CPU 0)
647  *	@call: the apm_bios_call registers.
648  *
649  *	If there is an error, it is returned in @call.err.
650  */
651 static int apm_bios_call(struct apm_bios_call *call)
652 {
653 	return on_cpu0(__apm_bios_call, call);
654 }
655 
656 /**
657  *	__apm_bios_call_simple - Make an APM BIOS 32bit call (on CPU 0)
658  *	@_call: pointer to struct apm_bios_call.
659  *
660  *	Make a BIOS call that returns one value only, or just status.
661  *	If there is an error, then the error code is returned in AH
662  *	(bits 8-15 of eax) and this function returns non-zero (it can
663  *	also return -ENOMEM). This is used for simpler BIOS operations.
664  *	This call may hold interrupts off for a long time on some laptops.
665  *
666  *	Note: this makes the call on the current CPU.
667  */
668 static long __apm_bios_call_simple(void *_call)
669 {
670 	u8			error;
671 	APM_DECL_SEGS
672 	unsigned long		flags;
673 	int			cpu;
674 	struct desc_struct	save_desc_40;
675 	struct desc_struct	*gdt;
676 	struct apm_bios_call	*call = _call;
677 	u64			ibt;
678 
679 	cpu = get_cpu();
680 	BUG_ON(cpu != 0);
681 	gdt = get_cpu_gdt_rw(cpu);
682 	save_desc_40 = gdt[0x40 / 8];
683 	gdt[0x40 / 8] = bad_bios_desc;
684 
685 	apm_irq_save(flags);
686 	firmware_restrict_branch_speculation_start();
687 	ibt = ibt_save(true);
688 	APM_DO_SAVE_SEGS;
689 	error = apm_bios_call_simple_asm(call->func, call->ebx, call->ecx,
690 					 &call->eax);
691 	APM_DO_RESTORE_SEGS;
692 	ibt_restore(ibt);
693 	firmware_restrict_branch_speculation_end();
694 	apm_irq_restore(flags);
695 	gdt[0x40 / 8] = save_desc_40;
696 	put_cpu();
697 	return error;
698 }
699 
700 /**
701  *	apm_bios_call_simple	-	make a simple APM BIOS 32bit call
702  *	@func: APM function to invoke
703  *	@ebx_in: EBX register value for BIOS call
704  *	@ecx_in: ECX register value for BIOS call
705  *	@eax: EAX register on return from the BIOS call
706  *	@err: bits
707  *
708  *	Make a BIOS call that returns one value only, or just status.
709  *	If there is an error, then the error code is returned in @err
710  *	and this function returns non-zero. This is used for simpler
711  *	BIOS operations.  This call may hold interrupts off for a long
712  *	time on some laptops.
713  */
714 static int apm_bios_call_simple(u32 func, u32 ebx_in, u32 ecx_in, u32 *eax,
715 				int *err)
716 {
717 	struct apm_bios_call call;
718 	int ret;
719 
720 	call.func = func;
721 	call.ebx = ebx_in;
722 	call.ecx = ecx_in;
723 
724 	ret = on_cpu0(__apm_bios_call_simple, &call);
725 	*eax = call.eax;
726 	*err = call.err;
727 	return ret;
728 }
729 
730 /**
731  *	apm_driver_version	-	APM driver version
732  *	@val:	loaded with the APM version on return
733  *
734  *	Retrieve the APM version supported by the BIOS. This is only
735  *	supported for APM 1.1 or higher. An error indicates APM 1.0 is
736  *	probably present.
737  *
738  *	On entry val should point to a value indicating the APM driver
739  *	version with the high byte being the major and the low byte the
740  *	minor number both in BCD
741  *
742  *	On return it will hold the BIOS revision supported in the
743  *	same format.
744  */
745 
746 static int apm_driver_version(u_short *val)
747 {
748 	u32 eax;
749 	int err;
750 
751 	if (apm_bios_call_simple(APM_FUNC_VERSION, 0, *val, &eax, &err))
752 		return err;
753 	*val = eax;
754 	return APM_SUCCESS;
755 }
756 
757 /**
758  *	apm_get_event	-	get an APM event from the BIOS
759  *	@event: pointer to the event
760  *	@info: point to the event information
761  *
762  *	The APM BIOS provides a polled information for event
763  *	reporting. The BIOS expects to be polled at least every second
764  *	when events are pending. When a message is found the caller should
765  *	poll until no more messages are present.  However, this causes
766  *	problems on some laptops where a suspend event notification is
767  *	not cleared until it is acknowledged.
768  *
769  *	Additional information is returned in the info pointer, providing
770  *	that APM 1.2 is in use. If no messages are pending the value 0x80
771  *	is returned (No power management events pending).
772  */
773 static int apm_get_event(apm_event_t *event, apm_eventinfo_t *info)
774 {
775 	struct apm_bios_call call;
776 
777 	call.func = APM_FUNC_GET_EVENT;
778 	call.ebx = call.ecx = 0;
779 
780 	if (apm_bios_call(&call))
781 		return call.err;
782 
783 	*event = call.ebx;
784 	if (apm_info.connection_version < 0x0102)
785 		*info = ~0; /* indicate info not valid */
786 	else
787 		*info = call.ecx;
788 	return APM_SUCCESS;
789 }
790 
791 /**
792  *	set_power_state	-	set the power management state
793  *	@what: which items to transition
794  *	@state: state to transition to
795  *
796  *	Request an APM change of state for one or more system devices. The
797  *	processor state must be transitioned last of all. what holds the
798  *	class of device in the upper byte and the device number (0xFF for
799  *	all) for the object to be transitioned.
800  *
801  *	The state holds the state to transition to, which may in fact
802  *	be an acceptance of a BIOS requested state change.
803  */
804 
805 static int set_power_state(u_short what, u_short state)
806 {
807 	u32 eax;
808 	int err;
809 
810 	if (apm_bios_call_simple(APM_FUNC_SET_STATE, what, state, &eax, &err))
811 		return err;
812 	return APM_SUCCESS;
813 }
814 
815 /**
816  *	set_system_power_state - set system wide power state
817  *	@state: which state to enter
818  *
819  *	Transition the entire system into a new APM power state.
820  */
821 
822 static int set_system_power_state(u_short state)
823 {
824 	return set_power_state(APM_DEVICE_ALL, state);
825 }
826 
827 /**
828  *	apm_do_idle	-	perform power saving
829  *
830  *	This function notifies the BIOS that the processor is (in the view
831  *	of the OS) idle. It returns -1 in the event that the BIOS refuses
832  *	to handle the idle request. On a success the function returns 1
833  *	if the BIOS did clock slowing or 0 otherwise.
834  */
835 
836 static int apm_do_idle(void)
837 {
838 	u32 eax;
839 	u8 ret = 0;
840 	int idled = 0;
841 	int err = 0;
842 
843 	if (!need_resched()) {
844 		idled = 1;
845 		ret = apm_bios_call_simple(APM_FUNC_IDLE, 0, 0, &eax, &err);
846 	}
847 
848 	if (!idled)
849 		return 0;
850 
851 	if (ret) {
852 		static unsigned long t;
853 
854 		/* This always fails on some SMP boards running UP kernels.
855 		 * Only report the failure the first 5 times.
856 		 */
857 		if (++t < 5) {
858 			printk(KERN_DEBUG "apm_do_idle failed (%d)\n", err);
859 			t = jiffies;
860 		}
861 		return -1;
862 	}
863 	clock_slowed = (apm_info.bios.flags & APM_IDLE_SLOWS_CLOCK) != 0;
864 	return clock_slowed;
865 }
866 
867 /**
868  *	apm_do_busy	-	inform the BIOS the CPU is busy
869  *
870  *	Request that the BIOS brings the CPU back to full performance.
871  */
872 
873 static void apm_do_busy(void)
874 {
875 	u32 dummy;
876 	int err;
877 
878 	if (clock_slowed || ALWAYS_CALL_BUSY) {
879 		(void)apm_bios_call_simple(APM_FUNC_BUSY, 0, 0, &dummy, &err);
880 		clock_slowed = 0;
881 	}
882 }
883 
884 /*
885  * If no process has really been interested in
886  * the CPU for some time, we want to call BIOS
887  * power management - we probably want
888  * to conserve power.
889  */
890 #define IDLE_CALC_LIMIT	(HZ * 100)
891 #define IDLE_LEAKY_MAX	16
892 
893 /**
894  * apm_cpu_idle		-	cpu idling for APM capable Linux
895  *
896  * This is the idling function the kernel executes when APM is available. It
897  * tries to do BIOS powermanagement based on the average system idle time.
898  * Furthermore it calls the system default idle routine.
899  */
900 
901 static int apm_cpu_idle(struct cpuidle_device *dev,
902 	struct cpuidle_driver *drv, int index)
903 {
904 	static int use_apm_idle; /* = 0 */
905 	static unsigned int last_jiffies; /* = 0 */
906 	static u64 last_stime; /* = 0 */
907 	u64 stime, utime;
908 
909 	int apm_idle_done = 0;
910 	unsigned int jiffies_since_last_check = jiffies - last_jiffies;
911 	unsigned int bucket;
912 
913 recalc:
914 	task_cputime(current, &utime, &stime);
915 	if (jiffies_since_last_check > IDLE_CALC_LIMIT) {
916 		use_apm_idle = 0;
917 	} else if (jiffies_since_last_check > idle_period) {
918 		unsigned int idle_percentage;
919 
920 		idle_percentage = nsecs_to_jiffies(stime - last_stime);
921 		idle_percentage *= 100;
922 		idle_percentage /= jiffies_since_last_check;
923 		use_apm_idle = (idle_percentage > idle_threshold);
924 		if (apm_info.forbid_idle)
925 			use_apm_idle = 0;
926 	}
927 
928 	last_jiffies = jiffies;
929 	last_stime = stime;
930 
931 	bucket = IDLE_LEAKY_MAX;
932 
933 	while (!need_resched()) {
934 		if (use_apm_idle) {
935 			unsigned int t;
936 
937 			t = jiffies;
938 			switch (apm_do_idle()) {
939 			case 0:
940 				apm_idle_done = 1;
941 				if (t != jiffies) {
942 					if (bucket) {
943 						bucket = IDLE_LEAKY_MAX;
944 						continue;
945 					}
946 				} else if (bucket) {
947 					bucket--;
948 					continue;
949 				}
950 				break;
951 			case 1:
952 				apm_idle_done = 1;
953 				break;
954 			default: /* BIOS refused */
955 				break;
956 			}
957 		}
958 		default_idle();
959 		local_irq_disable();
960 		jiffies_since_last_check = jiffies - last_jiffies;
961 		if (jiffies_since_last_check > idle_period)
962 			goto recalc;
963 	}
964 
965 	if (apm_idle_done)
966 		apm_do_busy();
967 
968 	return index;
969 }
970 
971 /**
972  *	apm_power_off	-	ask the BIOS to power off
973  *
974  *	Handle the power off sequence. This is the one piece of code we
975  *	will execute even on SMP machines. In order to deal with BIOS
976  *	bugs we support real mode APM BIOS power off calls. We also make
977  *	the SMP call on CPU0 as some systems will only honour this call
978  *	on their first cpu.
979  */
980 
981 static void apm_power_off(void)
982 {
983 	/* Some bioses don't like being called from CPU != 0 */
984 	if (apm_info.realmode_power_off) {
985 		set_cpus_allowed_ptr(current, cpumask_of(0));
986 		machine_real_restart(MRR_APM);
987 	} else {
988 		(void)set_system_power_state(APM_STATE_OFF);
989 	}
990 }
991 
992 #ifdef CONFIG_APM_DO_ENABLE
993 
994 /**
995  *	apm_enable_power_management - enable BIOS APM power management
996  *	@enable: enable yes/no
997  *
998  *	Enable or disable the APM BIOS power services.
999  */
1000 
1001 static int apm_enable_power_management(int enable)
1002 {
1003 	u32 eax;
1004 	int err;
1005 
1006 	if ((enable == 0) && (apm_info.bios.flags & APM_BIOS_DISENGAGED))
1007 		return APM_NOT_ENGAGED;
1008 	if (apm_bios_call_simple(APM_FUNC_ENABLE_PM, APM_DEVICE_BALL,
1009 				 enable, &eax, &err))
1010 		return err;
1011 	if (enable)
1012 		apm_info.bios.flags &= ~APM_BIOS_DISABLED;
1013 	else
1014 		apm_info.bios.flags |= APM_BIOS_DISABLED;
1015 	return APM_SUCCESS;
1016 }
1017 #endif
1018 
1019 /**
1020  *	apm_get_power_status	-	get current power state
1021  *	@status: returned status
1022  *	@bat: battery info
1023  *	@life: estimated life
1024  *
1025  *	Obtain the current power status from the APM BIOS. We return a
1026  *	status which gives the rough battery status, and current power
1027  *	source. The bat value returned give an estimate as a percentage
1028  *	of life and a status value for the battery. The estimated life
1029  *	if reported is a lifetime in seconds/minutes at current power
1030  *	consumption.
1031  */
1032 
1033 static int apm_get_power_status(u_short *status, u_short *bat, u_short *life)
1034 {
1035 	struct apm_bios_call call;
1036 
1037 	call.func = APM_FUNC_GET_STATUS;
1038 	call.ebx = APM_DEVICE_ALL;
1039 	call.ecx = 0;
1040 
1041 	if (apm_info.get_power_status_broken)
1042 		return APM_32_UNSUPPORTED;
1043 	if (apm_bios_call(&call)) {
1044 		if (!call.err)
1045 			return APM_NO_ERROR;
1046 		return call.err;
1047 	}
1048 	*status = call.ebx;
1049 	*bat = call.ecx;
1050 	if (apm_info.get_power_status_swabinminutes) {
1051 		*life = swab16((u16)call.edx);
1052 		*life |= 0x8000;
1053 	} else
1054 		*life = call.edx;
1055 	return APM_SUCCESS;
1056 }
1057 
1058 #if 0
1059 static int apm_get_battery_status(u_short which, u_short *status,
1060 				  u_short *bat, u_short *life, u_short *nbat)
1061 {
1062 	u32 eax;
1063 	u32 ebx;
1064 	u32 ecx;
1065 	u32 edx;
1066 	u32 esi;
1067 
1068 	if (apm_info.connection_version < 0x0102) {
1069 		/* pretend we only have one battery. */
1070 		if (which != 1)
1071 			return APM_BAD_DEVICE;
1072 		*nbat = 1;
1073 		return apm_get_power_status(status, bat, life);
1074 	}
1075 
1076 	if (apm_bios_call(APM_FUNC_GET_STATUS, (0x8000 | (which)), 0, &eax,
1077 			  &ebx, &ecx, &edx, &esi))
1078 		return (eax >> 8) & 0xff;
1079 	*status = ebx;
1080 	*bat = ecx;
1081 	*life = edx;
1082 	*nbat = esi;
1083 	return APM_SUCCESS;
1084 }
1085 #endif
1086 
1087 /**
1088  *	apm_engage_power_management	-	enable PM on a device
1089  *	@device: identity of device
1090  *	@enable: on/off
1091  *
1092  *	Activate or deactivate power management on either a specific device
1093  *	or the entire system (%APM_DEVICE_ALL).
1094  */
1095 
1096 static int apm_engage_power_management(u_short device, int enable)
1097 {
1098 	u32 eax;
1099 	int err;
1100 
1101 	if ((enable == 0) && (device == APM_DEVICE_ALL)
1102 	    && (apm_info.bios.flags & APM_BIOS_DISABLED))
1103 		return APM_DISABLED;
1104 	if (apm_bios_call_simple(APM_FUNC_ENGAGE_PM, device, enable,
1105 				 &eax, &err))
1106 		return err;
1107 	if (device == APM_DEVICE_ALL) {
1108 		if (enable)
1109 			apm_info.bios.flags &= ~APM_BIOS_DISENGAGED;
1110 		else
1111 			apm_info.bios.flags |= APM_BIOS_DISENGAGED;
1112 	}
1113 	return APM_SUCCESS;
1114 }
1115 
1116 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1117 
1118 /**
1119  *	apm_console_blank	-	blank the display
1120  *	@blank: on/off
1121  *
1122  *	Attempt to blank the console, firstly by blanking just video device
1123  *	zero, and if that fails (some BIOSes don't support it) then it blanks
1124  *	all video devices. Typically the BIOS will do laptop backlight and
1125  *	monitor powerdown for us.
1126  */
1127 
1128 static int apm_console_blank(int blank)
1129 {
1130 	int error = APM_NOT_ENGAGED; /* silence gcc */
1131 	int i;
1132 	u_short state;
1133 	static const u_short dev[3] = { 0x100, 0x1FF, 0x101 };
1134 
1135 	state = blank ? APM_STATE_STANDBY : APM_STATE_READY;
1136 
1137 	for (i = 0; i < ARRAY_SIZE(dev); i++) {
1138 		error = set_power_state(dev[i], state);
1139 
1140 		if ((error == APM_SUCCESS) || (error == APM_NO_ERROR))
1141 			return 1;
1142 
1143 		if (error == APM_NOT_ENGAGED)
1144 			break;
1145 	}
1146 
1147 	if (error == APM_NOT_ENGAGED) {
1148 		static int tried;
1149 		int eng_error;
1150 		if (tried++ == 0) {
1151 			eng_error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1152 			if (eng_error) {
1153 				apm_error("set display", error);
1154 				apm_error("engage interface", eng_error);
1155 				return 0;
1156 			} else
1157 				return apm_console_blank(blank);
1158 		}
1159 	}
1160 	apm_error("set display", error);
1161 	return 0;
1162 }
1163 #endif
1164 
1165 static int queue_empty(struct apm_user *as)
1166 {
1167 	return as->event_head == as->event_tail;
1168 }
1169 
1170 static apm_event_t get_queued_event(struct apm_user *as)
1171 {
1172 	if (++as->event_tail >= APM_MAX_EVENTS)
1173 		as->event_tail = 0;
1174 	return as->events[as->event_tail];
1175 }
1176 
1177 static void queue_event(apm_event_t event, struct apm_user *sender)
1178 {
1179 	struct apm_user *as;
1180 
1181 	spin_lock(&user_list_lock);
1182 	if (user_list == NULL)
1183 		goto out;
1184 	for (as = user_list; as != NULL; as = as->next) {
1185 		if ((as == sender) || (!as->reader))
1186 			continue;
1187 		if (++as->event_head >= APM_MAX_EVENTS)
1188 			as->event_head = 0;
1189 
1190 		if (as->event_head == as->event_tail) {
1191 			static int notified;
1192 
1193 			if (notified++ == 0)
1194 				pr_err("an event queue overflowed\n");
1195 			if (++as->event_tail >= APM_MAX_EVENTS)
1196 				as->event_tail = 0;
1197 		}
1198 		as->events[as->event_head] = event;
1199 		if (!as->suser || !as->writer)
1200 			continue;
1201 		switch (event) {
1202 		case APM_SYS_SUSPEND:
1203 		case APM_USER_SUSPEND:
1204 			as->suspends_pending++;
1205 			suspends_pending++;
1206 			break;
1207 
1208 		case APM_SYS_STANDBY:
1209 		case APM_USER_STANDBY:
1210 			as->standbys_pending++;
1211 			standbys_pending++;
1212 			break;
1213 		}
1214 	}
1215 	wake_up_interruptible(&apm_waitqueue);
1216 out:
1217 	spin_unlock(&user_list_lock);
1218 }
1219 
1220 static void reinit_timer(void)
1221 {
1222 #ifdef INIT_TIMER_AFTER_SUSPEND
1223 	unsigned long flags;
1224 
1225 	raw_spin_lock_irqsave(&i8253_lock, flags);
1226 	/* set the clock to HZ */
1227 	outb_p(0x34, PIT_MODE);		/* binary, mode 2, LSB/MSB, ch 0 */
1228 	udelay(10);
1229 	outb_p(LATCH & 0xff, PIT_CH0);	/* LSB */
1230 	udelay(10);
1231 	outb_p(LATCH >> 8, PIT_CH0);	/* MSB */
1232 	udelay(10);
1233 	raw_spin_unlock_irqrestore(&i8253_lock, flags);
1234 #endif
1235 }
1236 
1237 static int suspend(int vetoable)
1238 {
1239 	int err;
1240 	struct apm_user	*as;
1241 
1242 	dpm_suspend_start(PMSG_SUSPEND);
1243 	dpm_suspend_end(PMSG_SUSPEND);
1244 
1245 	local_irq_disable();
1246 	syscore_suspend();
1247 
1248 	local_irq_enable();
1249 
1250 	save_processor_state();
1251 	err = set_system_power_state(APM_STATE_SUSPEND);
1252 	ignore_normal_resume = 1;
1253 	restore_processor_state();
1254 
1255 	local_irq_disable();
1256 	reinit_timer();
1257 
1258 	if (err == APM_NO_ERROR)
1259 		err = APM_SUCCESS;
1260 	if (err != APM_SUCCESS)
1261 		apm_error("suspend", err);
1262 	err = (err == APM_SUCCESS) ? 0 : -EIO;
1263 
1264 	syscore_resume();
1265 	local_irq_enable();
1266 
1267 	dpm_resume_start(PMSG_RESUME);
1268 	dpm_resume_end(PMSG_RESUME);
1269 
1270 	queue_event(APM_NORMAL_RESUME, NULL);
1271 	spin_lock(&user_list_lock);
1272 	for (as = user_list; as != NULL; as = as->next) {
1273 		as->suspend_wait = 0;
1274 		as->suspend_result = err;
1275 	}
1276 	spin_unlock(&user_list_lock);
1277 	wake_up_interruptible(&apm_suspend_waitqueue);
1278 	return err;
1279 }
1280 
1281 static void standby(void)
1282 {
1283 	int err;
1284 
1285 	dpm_suspend_end(PMSG_SUSPEND);
1286 
1287 	local_irq_disable();
1288 	syscore_suspend();
1289 	local_irq_enable();
1290 
1291 	err = set_system_power_state(APM_STATE_STANDBY);
1292 	if ((err != APM_SUCCESS) && (err != APM_NO_ERROR))
1293 		apm_error("standby", err);
1294 
1295 	local_irq_disable();
1296 	syscore_resume();
1297 	local_irq_enable();
1298 
1299 	dpm_resume_start(PMSG_RESUME);
1300 }
1301 
1302 static apm_event_t get_event(void)
1303 {
1304 	int error;
1305 	apm_event_t event = APM_NO_EVENTS; /* silence gcc */
1306 	apm_eventinfo_t	info;
1307 
1308 	static int notified;
1309 
1310 	/* we don't use the eventinfo */
1311 	error = apm_get_event(&event, &info);
1312 	if (error == APM_SUCCESS)
1313 		return event;
1314 
1315 	if ((error != APM_NO_EVENTS) && (notified++ == 0))
1316 		apm_error("get_event", error);
1317 
1318 	return 0;
1319 }
1320 
1321 static void check_events(void)
1322 {
1323 	apm_event_t event;
1324 	static unsigned long last_resume;
1325 	static int ignore_bounce;
1326 
1327 	while ((event = get_event()) != 0) {
1328 		if (debug) {
1329 			if (event <= NR_APM_EVENT_NAME)
1330 				printk(KERN_DEBUG "apm: received %s notify\n",
1331 				       apm_event_name[event - 1]);
1332 			else
1333 				printk(KERN_DEBUG "apm: received unknown "
1334 				       "event 0x%02x\n", event);
1335 		}
1336 		if (ignore_bounce
1337 		    && (time_after(jiffies, last_resume + bounce_interval)))
1338 			ignore_bounce = 0;
1339 
1340 		switch (event) {
1341 		case APM_SYS_STANDBY:
1342 		case APM_USER_STANDBY:
1343 			queue_event(event, NULL);
1344 			if (standbys_pending <= 0)
1345 				standby();
1346 			break;
1347 
1348 		case APM_USER_SUSPEND:
1349 #ifdef CONFIG_APM_IGNORE_USER_SUSPEND
1350 			if (apm_info.connection_version > 0x100)
1351 				set_system_power_state(APM_STATE_REJECT);
1352 			break;
1353 #endif
1354 		case APM_SYS_SUSPEND:
1355 			if (ignore_bounce) {
1356 				if (apm_info.connection_version > 0x100)
1357 					set_system_power_state(APM_STATE_REJECT);
1358 				break;
1359 			}
1360 			/*
1361 			 * If we are already processing a SUSPEND,
1362 			 * then further SUSPEND events from the BIOS
1363 			 * will be ignored.  We also return here to
1364 			 * cope with the fact that the Thinkpads keep
1365 			 * sending a SUSPEND event until something else
1366 			 * happens!
1367 			 */
1368 			if (ignore_sys_suspend)
1369 				return;
1370 			ignore_sys_suspend = 1;
1371 			queue_event(event, NULL);
1372 			if (suspends_pending <= 0)
1373 				(void) suspend(1);
1374 			break;
1375 
1376 		case APM_NORMAL_RESUME:
1377 		case APM_CRITICAL_RESUME:
1378 		case APM_STANDBY_RESUME:
1379 			ignore_sys_suspend = 0;
1380 			last_resume = jiffies;
1381 			ignore_bounce = 1;
1382 			if ((event != APM_NORMAL_RESUME)
1383 			    || (ignore_normal_resume == 0)) {
1384 				dpm_resume_end(PMSG_RESUME);
1385 				queue_event(event, NULL);
1386 			}
1387 			ignore_normal_resume = 0;
1388 			break;
1389 
1390 		case APM_CAPABILITY_CHANGE:
1391 		case APM_LOW_BATTERY:
1392 		case APM_POWER_STATUS_CHANGE:
1393 			queue_event(event, NULL);
1394 			/* If needed, notify drivers here */
1395 			break;
1396 
1397 		case APM_UPDATE_TIME:
1398 			break;
1399 
1400 		case APM_CRITICAL_SUSPEND:
1401 			/*
1402 			 * We are not allowed to reject a critical suspend.
1403 			 */
1404 			(void)suspend(0);
1405 			break;
1406 		}
1407 	}
1408 }
1409 
1410 static void apm_event_handler(void)
1411 {
1412 	static int pending_count = 4;
1413 	int err;
1414 
1415 	if ((standbys_pending > 0) || (suspends_pending > 0)) {
1416 		if ((apm_info.connection_version > 0x100) &&
1417 		    (pending_count-- <= 0)) {
1418 			pending_count = 4;
1419 			if (debug)
1420 				printk(KERN_DEBUG "apm: setting state busy\n");
1421 			err = set_system_power_state(APM_STATE_BUSY);
1422 			if (err)
1423 				apm_error("busy", err);
1424 		}
1425 	} else
1426 		pending_count = 4;
1427 	check_events();
1428 }
1429 
1430 /*
1431  * This is the APM thread main loop.
1432  */
1433 
1434 static void apm_mainloop(void)
1435 {
1436 	DECLARE_WAITQUEUE(wait, current);
1437 
1438 	add_wait_queue(&apm_waitqueue, &wait);
1439 	set_current_state(TASK_INTERRUPTIBLE);
1440 	for (;;) {
1441 		schedule_timeout(APM_CHECK_TIMEOUT);
1442 		if (kthread_should_stop())
1443 			break;
1444 		/*
1445 		 * Ok, check all events, check for idle (and mark us sleeping
1446 		 * so as not to count towards the load average)..
1447 		 */
1448 		set_current_state(TASK_INTERRUPTIBLE);
1449 		apm_event_handler();
1450 	}
1451 	remove_wait_queue(&apm_waitqueue, &wait);
1452 }
1453 
1454 static int check_apm_user(struct apm_user *as, const char *func)
1455 {
1456 	if (as == NULL || as->magic != APM_BIOS_MAGIC) {
1457 		pr_err("%s passed bad filp\n", func);
1458 		return 1;
1459 	}
1460 	return 0;
1461 }
1462 
1463 static ssize_t do_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
1464 {
1465 	struct apm_user *as;
1466 	int i;
1467 	apm_event_t event;
1468 
1469 	as = fp->private_data;
1470 	if (check_apm_user(as, "read"))
1471 		return -EIO;
1472 	if ((int)count < sizeof(apm_event_t))
1473 		return -EINVAL;
1474 	if ((queue_empty(as)) && (fp->f_flags & O_NONBLOCK))
1475 		return -EAGAIN;
1476 	wait_event_interruptible(apm_waitqueue, !queue_empty(as));
1477 	i = count;
1478 	while ((i >= sizeof(event)) && !queue_empty(as)) {
1479 		event = get_queued_event(as);
1480 		if (copy_to_user(buf, &event, sizeof(event))) {
1481 			if (i < count)
1482 				break;
1483 			return -EFAULT;
1484 		}
1485 		switch (event) {
1486 		case APM_SYS_SUSPEND:
1487 		case APM_USER_SUSPEND:
1488 			as->suspends_read++;
1489 			break;
1490 
1491 		case APM_SYS_STANDBY:
1492 		case APM_USER_STANDBY:
1493 			as->standbys_read++;
1494 			break;
1495 		}
1496 		buf += sizeof(event);
1497 		i -= sizeof(event);
1498 	}
1499 	if (i < count)
1500 		return count - i;
1501 	if (signal_pending(current))
1502 		return -ERESTARTSYS;
1503 	return 0;
1504 }
1505 
1506 static __poll_t do_poll(struct file *fp, poll_table *wait)
1507 {
1508 	struct apm_user *as;
1509 
1510 	as = fp->private_data;
1511 	if (check_apm_user(as, "poll"))
1512 		return 0;
1513 	poll_wait(fp, &apm_waitqueue, wait);
1514 	if (!queue_empty(as))
1515 		return EPOLLIN | EPOLLRDNORM;
1516 	return 0;
1517 }
1518 
1519 static long do_ioctl(struct file *filp, u_int cmd, u_long arg)
1520 {
1521 	struct apm_user *as;
1522 	int ret;
1523 
1524 	as = filp->private_data;
1525 	if (check_apm_user(as, "ioctl"))
1526 		return -EIO;
1527 	if (!as->suser || !as->writer)
1528 		return -EPERM;
1529 	switch (cmd) {
1530 	case APM_IOC_STANDBY:
1531 		mutex_lock(&apm_mutex);
1532 		if (as->standbys_read > 0) {
1533 			as->standbys_read--;
1534 			as->standbys_pending--;
1535 			standbys_pending--;
1536 		} else
1537 			queue_event(APM_USER_STANDBY, as);
1538 		if (standbys_pending <= 0)
1539 			standby();
1540 		mutex_unlock(&apm_mutex);
1541 		break;
1542 	case APM_IOC_SUSPEND:
1543 		mutex_lock(&apm_mutex);
1544 		if (as->suspends_read > 0) {
1545 			as->suspends_read--;
1546 			as->suspends_pending--;
1547 			suspends_pending--;
1548 		} else
1549 			queue_event(APM_USER_SUSPEND, as);
1550 		if (suspends_pending <= 0) {
1551 			ret = suspend(1);
1552 			mutex_unlock(&apm_mutex);
1553 		} else {
1554 			as->suspend_wait = 1;
1555 			mutex_unlock(&apm_mutex);
1556 			wait_event_interruptible(apm_suspend_waitqueue,
1557 					as->suspend_wait == 0);
1558 			ret = as->suspend_result;
1559 		}
1560 		return ret;
1561 	default:
1562 		return -ENOTTY;
1563 	}
1564 	return 0;
1565 }
1566 
1567 static int do_release(struct inode *inode, struct file *filp)
1568 {
1569 	struct apm_user *as;
1570 
1571 	as = filp->private_data;
1572 	if (check_apm_user(as, "release"))
1573 		return 0;
1574 	filp->private_data = NULL;
1575 	if (as->standbys_pending > 0) {
1576 		standbys_pending -= as->standbys_pending;
1577 		if (standbys_pending <= 0)
1578 			standby();
1579 	}
1580 	if (as->suspends_pending > 0) {
1581 		suspends_pending -= as->suspends_pending;
1582 		if (suspends_pending <= 0)
1583 			(void) suspend(1);
1584 	}
1585 	spin_lock(&user_list_lock);
1586 	if (user_list == as)
1587 		user_list = as->next;
1588 	else {
1589 		struct apm_user *as1;
1590 
1591 		for (as1 = user_list;
1592 		     (as1 != NULL) && (as1->next != as);
1593 		     as1 = as1->next)
1594 			;
1595 		if (as1 == NULL)
1596 			pr_err("filp not in user list\n");
1597 		else
1598 			as1->next = as->next;
1599 	}
1600 	spin_unlock(&user_list_lock);
1601 	kfree(as);
1602 	return 0;
1603 }
1604 
1605 static int do_open(struct inode *inode, struct file *filp)
1606 {
1607 	struct apm_user *as;
1608 
1609 	as = kmalloc(sizeof(*as), GFP_KERNEL);
1610 	if (as == NULL)
1611 		return -ENOMEM;
1612 
1613 	as->magic = APM_BIOS_MAGIC;
1614 	as->event_tail = as->event_head = 0;
1615 	as->suspends_pending = as->standbys_pending = 0;
1616 	as->suspends_read = as->standbys_read = 0;
1617 	/*
1618 	 * XXX - this is a tiny bit broken, when we consider BSD
1619 	 * process accounting. If the device is opened by root, we
1620 	 * instantly flag that we used superuser privs. Who knows,
1621 	 * we might close the device immediately without doing a
1622 	 * privileged operation -- cevans
1623 	 */
1624 	as->suser = capable(CAP_SYS_ADMIN);
1625 	as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
1626 	as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
1627 	spin_lock(&user_list_lock);
1628 	as->next = user_list;
1629 	user_list = as;
1630 	spin_unlock(&user_list_lock);
1631 	filp->private_data = as;
1632 	return 0;
1633 }
1634 
1635 #ifdef CONFIG_PROC_FS
1636 static int proc_apm_show(struct seq_file *m, void *v)
1637 {
1638 	unsigned short	bx;
1639 	unsigned short	cx;
1640 	unsigned short	dx;
1641 	int		error;
1642 	unsigned short  ac_line_status = 0xff;
1643 	unsigned short  battery_status = 0xff;
1644 	unsigned short  battery_flag   = 0xff;
1645 	int		percentage     = -1;
1646 	int             time_units     = -1;
1647 	char            *units         = "?";
1648 
1649 	if ((num_online_cpus() == 1) &&
1650 	    !(error = apm_get_power_status(&bx, &cx, &dx))) {
1651 		ac_line_status = (bx >> 8) & 0xff;
1652 		battery_status = bx & 0xff;
1653 		if ((cx & 0xff) != 0xff)
1654 			percentage = cx & 0xff;
1655 
1656 		if (apm_info.connection_version > 0x100) {
1657 			battery_flag = (cx >> 8) & 0xff;
1658 			if (dx != 0xffff) {
1659 				units = (dx & 0x8000) ? "min" : "sec";
1660 				time_units = dx & 0x7fff;
1661 			}
1662 		}
1663 	}
1664 	/* Arguments, with symbols from linux/apm_bios.h.  Information is
1665 	   from the Get Power Status (0x0a) call unless otherwise noted.
1666 
1667 	   0) Linux driver version (this will change if format changes)
1668 	   1) APM BIOS Version.  Usually 1.0, 1.1 or 1.2.
1669 	   2) APM flags from APM Installation Check (0x00):
1670 	      bit 0: APM_16_BIT_SUPPORT
1671 	      bit 1: APM_32_BIT_SUPPORT
1672 	      bit 2: APM_IDLE_SLOWS_CLOCK
1673 	      bit 3: APM_BIOS_DISABLED
1674 	      bit 4: APM_BIOS_DISENGAGED
1675 	   3) AC line status
1676 	      0x00: Off-line
1677 	      0x01: On-line
1678 	      0x02: On backup power (BIOS >= 1.1 only)
1679 	      0xff: Unknown
1680 	   4) Battery status
1681 	      0x00: High
1682 	      0x01: Low
1683 	      0x02: Critical
1684 	      0x03: Charging
1685 	      0x04: Selected battery not present (BIOS >= 1.2 only)
1686 	      0xff: Unknown
1687 	   5) Battery flag
1688 	      bit 0: High
1689 	      bit 1: Low
1690 	      bit 2: Critical
1691 	      bit 3: Charging
1692 	      bit 7: No system battery
1693 	      0xff: Unknown
1694 	   6) Remaining battery life (percentage of charge):
1695 	      0-100: valid
1696 	      -1: Unknown
1697 	   7) Remaining battery life (time units):
1698 	      Number of remaining minutes or seconds
1699 	      -1: Unknown
1700 	   8) min = minutes; sec = seconds */
1701 
1702 	seq_printf(m, "%s %d.%d 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
1703 		   driver_version,
1704 		   (apm_info.bios.version >> 8) & 0xff,
1705 		   apm_info.bios.version & 0xff,
1706 		   apm_info.bios.flags,
1707 		   ac_line_status,
1708 		   battery_status,
1709 		   battery_flag,
1710 		   percentage,
1711 		   time_units,
1712 		   units);
1713 	return 0;
1714 }
1715 #endif
1716 
1717 static int apm(void *unused)
1718 {
1719 	unsigned short	bx;
1720 	unsigned short	cx;
1721 	unsigned short	dx;
1722 	int		error;
1723 	char 		*power_stat;
1724 	char 		*bat_stat;
1725 
1726 	/* 2002/08/01 - WT
1727 	 * This is to avoid random crashes at boot time during initialization
1728 	 * on SMP systems in case of "apm=power-off" mode. Seen on ASUS A7M266D.
1729 	 * Some bioses don't like being called from CPU != 0.
1730 	 * Method suggested by Ingo Molnar.
1731 	 */
1732 	set_cpus_allowed_ptr(current, cpumask_of(0));
1733 	BUG_ON(smp_processor_id() != 0);
1734 
1735 	if (apm_info.connection_version == 0) {
1736 		apm_info.connection_version = apm_info.bios.version;
1737 		if (apm_info.connection_version > 0x100) {
1738 			/*
1739 			 * We only support BIOSs up to version 1.2
1740 			 */
1741 			if (apm_info.connection_version > 0x0102)
1742 				apm_info.connection_version = 0x0102;
1743 			error = apm_driver_version(&apm_info.connection_version);
1744 			if (error != APM_SUCCESS) {
1745 				apm_error("driver version", error);
1746 				/* Fall back to an APM 1.0 connection. */
1747 				apm_info.connection_version = 0x100;
1748 			}
1749 		}
1750 	}
1751 
1752 	if (debug)
1753 		printk(KERN_INFO "apm: Connection version %d.%d\n",
1754 			(apm_info.connection_version >> 8) & 0xff,
1755 			apm_info.connection_version & 0xff);
1756 
1757 #ifdef CONFIG_APM_DO_ENABLE
1758 	if (apm_info.bios.flags & APM_BIOS_DISABLED) {
1759 		/*
1760 		 * This call causes my NEC UltraLite Versa 33/C to hang if it
1761 		 * is booted with PM disabled but not in the docking station.
1762 		 * Unfortunate ...
1763 		 */
1764 		error = apm_enable_power_management(1);
1765 		if (error) {
1766 			apm_error("enable power management", error);
1767 			return -1;
1768 		}
1769 	}
1770 #endif
1771 
1772 	if ((apm_info.bios.flags & APM_BIOS_DISENGAGED)
1773 	    && (apm_info.connection_version > 0x0100)) {
1774 		error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1775 		if (error) {
1776 			apm_error("engage power management", error);
1777 			return -1;
1778 		}
1779 	}
1780 
1781 	if (debug && (num_online_cpus() == 1 || smp)) {
1782 		error = apm_get_power_status(&bx, &cx, &dx);
1783 		if (error)
1784 			printk(KERN_INFO "apm: power status not available\n");
1785 		else {
1786 			switch ((bx >> 8) & 0xff) {
1787 			case 0:
1788 				power_stat = "off line";
1789 				break;
1790 			case 1:
1791 				power_stat = "on line";
1792 				break;
1793 			case 2:
1794 				power_stat = "on backup power";
1795 				break;
1796 			default:
1797 				power_stat = "unknown";
1798 				break;
1799 			}
1800 			switch (bx & 0xff) {
1801 			case 0:
1802 				bat_stat = "high";
1803 				break;
1804 			case 1:
1805 				bat_stat = "low";
1806 				break;
1807 			case 2:
1808 				bat_stat = "critical";
1809 				break;
1810 			case 3:
1811 				bat_stat = "charging";
1812 				break;
1813 			default:
1814 				bat_stat = "unknown";
1815 				break;
1816 			}
1817 			printk(KERN_INFO
1818 			       "apm: AC %s, battery status %s, battery life ",
1819 			       power_stat, bat_stat);
1820 			if ((cx & 0xff) == 0xff)
1821 				printk("unknown\n");
1822 			else
1823 				printk("%d%%\n", cx & 0xff);
1824 			if (apm_info.connection_version > 0x100) {
1825 				printk(KERN_INFO
1826 				       "apm: battery flag 0x%02x, battery life ",
1827 				       (cx >> 8) & 0xff);
1828 				if (dx == 0xffff)
1829 					printk("unknown\n");
1830 				else
1831 					printk("%d %s\n", dx & 0x7fff,
1832 					       (dx & 0x8000) ?
1833 					       "minutes" : "seconds");
1834 			}
1835 		}
1836 	}
1837 
1838 	/* Install our power off handler.. */
1839 	if (power_off)
1840 		pm_power_off = apm_power_off;
1841 
1842 	if (num_online_cpus() == 1 || smp) {
1843 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1844 		console_blank_hook = apm_console_blank;
1845 #endif
1846 		apm_mainloop();
1847 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1848 		console_blank_hook = NULL;
1849 #endif
1850 	}
1851 
1852 	return 0;
1853 }
1854 
1855 #ifndef MODULE
1856 static int __init apm_setup(char *str)
1857 {
1858 	int invert;
1859 
1860 	while ((str != NULL) && (*str != '\0')) {
1861 		if (strncmp(str, "off", 3) == 0)
1862 			apm_disabled = 1;
1863 		if (strncmp(str, "on", 2) == 0)
1864 			apm_disabled = 0;
1865 		if ((strncmp(str, "bounce-interval=", 16) == 0) ||
1866 		    (strncmp(str, "bounce_interval=", 16) == 0))
1867 			bounce_interval = simple_strtol(str + 16, NULL, 0);
1868 		if ((strncmp(str, "idle-threshold=", 15) == 0) ||
1869 		    (strncmp(str, "idle_threshold=", 15) == 0))
1870 			idle_threshold = simple_strtol(str + 15, NULL, 0);
1871 		if ((strncmp(str, "idle-period=", 12) == 0) ||
1872 		    (strncmp(str, "idle_period=", 12) == 0))
1873 			idle_period = simple_strtol(str + 12, NULL, 0);
1874 		invert = (strncmp(str, "no-", 3) == 0) ||
1875 			(strncmp(str, "no_", 3) == 0);
1876 		if (invert)
1877 			str += 3;
1878 		if (strncmp(str, "debug", 5) == 0)
1879 			debug = !invert;
1880 		if ((strncmp(str, "power-off", 9) == 0) ||
1881 		    (strncmp(str, "power_off", 9) == 0))
1882 			power_off = !invert;
1883 		if (strncmp(str, "smp", 3) == 0) {
1884 			smp = !invert;
1885 			idle_threshold = 100;
1886 		}
1887 		if ((strncmp(str, "allow-ints", 10) == 0) ||
1888 		    (strncmp(str, "allow_ints", 10) == 0))
1889 			apm_info.allow_ints = !invert;
1890 		if ((strncmp(str, "broken-psr", 10) == 0) ||
1891 		    (strncmp(str, "broken_psr", 10) == 0))
1892 			apm_info.get_power_status_broken = !invert;
1893 		if ((strncmp(str, "realmode-power-off", 18) == 0) ||
1894 		    (strncmp(str, "realmode_power_off", 18) == 0))
1895 			apm_info.realmode_power_off = !invert;
1896 		str = strchr(str, ',');
1897 		if (str != NULL)
1898 			str += strspn(str, ", \t");
1899 	}
1900 	return 1;
1901 }
1902 
1903 __setup("apm=", apm_setup);
1904 #endif
1905 
1906 static const struct file_operations apm_bios_fops = {
1907 	.owner		= THIS_MODULE,
1908 	.read		= do_read,
1909 	.poll		= do_poll,
1910 	.unlocked_ioctl	= do_ioctl,
1911 	.open		= do_open,
1912 	.release	= do_release,
1913 	.llseek		= noop_llseek,
1914 };
1915 
1916 static struct miscdevice apm_device = {
1917 	APM_MINOR_DEV,
1918 	"apm_bios",
1919 	&apm_bios_fops
1920 };
1921 
1922 
1923 /* Simple "print if true" callback */
1924 static int __init print_if_true(const struct dmi_system_id *d)
1925 {
1926 	printk("%s\n", d->ident);
1927 	return 0;
1928 }
1929 
1930 /*
1931  * Some Bioses enable the PS/2 mouse (touchpad) at resume, even if it was
1932  * disabled before the suspend. Linux used to get terribly confused by that.
1933  */
1934 static int __init broken_ps2_resume(const struct dmi_system_id *d)
1935 {
1936 	printk(KERN_INFO "%s machine detected. Mousepad Resume Bug "
1937 	       "workaround hopefully not needed.\n", d->ident);
1938 	return 0;
1939 }
1940 
1941 /* Some bioses have a broken protected mode poweroff and need to use realmode */
1942 static int __init set_realmode_power_off(const struct dmi_system_id *d)
1943 {
1944 	if (apm_info.realmode_power_off == 0) {
1945 		apm_info.realmode_power_off = 1;
1946 		printk(KERN_INFO "%s bios detected. "
1947 		       "Using realmode poweroff only.\n", d->ident);
1948 	}
1949 	return 0;
1950 }
1951 
1952 /* Some laptops require interrupts to be enabled during APM calls */
1953 static int __init set_apm_ints(const struct dmi_system_id *d)
1954 {
1955 	if (apm_info.allow_ints == 0) {
1956 		apm_info.allow_ints = 1;
1957 		printk(KERN_INFO "%s machine detected. "
1958 		       "Enabling interrupts during APM calls.\n", d->ident);
1959 	}
1960 	return 0;
1961 }
1962 
1963 /* Some APM bioses corrupt memory or just plain do not work */
1964 static int __init apm_is_horked(const struct dmi_system_id *d)
1965 {
1966 	if (apm_info.disabled == 0) {
1967 		apm_info.disabled = 1;
1968 		printk(KERN_INFO "%s machine detected. "
1969 		       "Disabling APM.\n", d->ident);
1970 	}
1971 	return 0;
1972 }
1973 
1974 static int __init apm_is_horked_d850md(const struct dmi_system_id *d)
1975 {
1976 	if (apm_info.disabled == 0) {
1977 		apm_info.disabled = 1;
1978 		printk(KERN_INFO "%s machine detected. "
1979 		       "Disabling APM.\n", d->ident);
1980 		printk(KERN_INFO "This bug is fixed in bios P15 which is available for\n");
1981 		printk(KERN_INFO "download from support.intel.com\n");
1982 	}
1983 	return 0;
1984 }
1985 
1986 /* Some APM bioses hang on APM idle calls */
1987 static int __init apm_likes_to_melt(const struct dmi_system_id *d)
1988 {
1989 	if (apm_info.forbid_idle == 0) {
1990 		apm_info.forbid_idle = 1;
1991 		printk(KERN_INFO "%s machine detected. "
1992 		       "Disabling APM idle calls.\n", d->ident);
1993 	}
1994 	return 0;
1995 }
1996 
1997 /*
1998  *  Check for clue free BIOS implementations who use
1999  *  the following QA technique
2000  *
2001  *      [ Write BIOS Code ]<------
2002  *               |                ^
2003  *      < Does it Compile >----N--
2004  *               |Y               ^
2005  *	< Does it Boot Win98 >-N--
2006  *               |Y
2007  *           [Ship It]
2008  *
2009  *	Phoenix A04  08/24/2000 is known bad (Dell Inspiron 5000e)
2010  *	Phoenix A07  09/29/2000 is known good (Dell Inspiron 5000)
2011  */
2012 static int __init broken_apm_power(const struct dmi_system_id *d)
2013 {
2014 	apm_info.get_power_status_broken = 1;
2015 	printk(KERN_WARNING "BIOS strings suggest APM bugs, "
2016 	       "disabling power status reporting.\n");
2017 	return 0;
2018 }
2019 
2020 /*
2021  * This bios swaps the APM minute reporting bytes over (Many sony laptops
2022  * have this problem).
2023  */
2024 static int __init swab_apm_power_in_minutes(const struct dmi_system_id *d)
2025 {
2026 	apm_info.get_power_status_swabinminutes = 1;
2027 	printk(KERN_WARNING "BIOS strings suggest APM reports battery life "
2028 	       "in minutes and wrong byte order.\n");
2029 	return 0;
2030 }
2031 
2032 static const struct dmi_system_id apm_dmi_table[] __initconst = {
2033 	{
2034 		print_if_true,
2035 		KERN_WARNING "IBM T23 - BIOS 1.03b+ and controller firmware 1.02+ may be needed for Linux APM.",
2036 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
2037 			DMI_MATCH(DMI_BIOS_VERSION, "1AET38WW (1.01b)"), },
2038 	},
2039 	{	/* Handle problems with APM on the C600 */
2040 		broken_ps2_resume, "Dell Latitude C600",
2041 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
2042 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C600"), },
2043 	},
2044 	{	/* Allow interrupts during suspend on Dell Latitude laptops*/
2045 		set_apm_ints, "Dell Latitude",
2046 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2047 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C510"), }
2048 	},
2049 	{	/* APM crashes */
2050 		apm_is_horked, "Dell Inspiron 2500",
2051 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2052 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2053 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2054 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2055 	},
2056 	{	/* Allow interrupts during suspend on Dell Inspiron laptops*/
2057 		set_apm_ints, "Dell Inspiron", {
2058 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2059 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 4000"), },
2060 	},
2061 	{	/* Handle problems with APM on Inspiron 5000e */
2062 		broken_apm_power, "Dell Inspiron 5000e",
2063 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2064 			DMI_MATCH(DMI_BIOS_VERSION, "A04"),
2065 			DMI_MATCH(DMI_BIOS_DATE, "08/24/2000"), },
2066 	},
2067 	{	/* Handle problems with APM on Inspiron 2500 */
2068 		broken_apm_power, "Dell Inspiron 2500",
2069 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2070 			DMI_MATCH(DMI_BIOS_VERSION, "A12"),
2071 			DMI_MATCH(DMI_BIOS_DATE, "02/04/2002"), },
2072 	},
2073 	{	/* APM crashes */
2074 		apm_is_horked, "Dell Dimension 4100",
2075 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2076 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"),
2077 			DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2078 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2079 	},
2080 	{	/* Allow interrupts during suspend on Compaq Laptops*/
2081 		set_apm_ints, "Compaq 12XL125",
2082 		{	DMI_MATCH(DMI_SYS_VENDOR, "Compaq"),
2083 			DMI_MATCH(DMI_PRODUCT_NAME, "Compaq PC"),
2084 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2085 			DMI_MATCH(DMI_BIOS_VERSION, "4.06"), },
2086 	},
2087 	{	/* Allow interrupts during APM or the clock goes slow */
2088 		set_apm_ints, "ASUSTeK",
2089 		{	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
2090 			DMI_MATCH(DMI_PRODUCT_NAME, "L8400K series Notebook PC"), },
2091 	},
2092 	{	/* APM blows on shutdown */
2093 		apm_is_horked, "ABIT KX7-333[R]",
2094 		{	DMI_MATCH(DMI_BOARD_VENDOR, "ABIT"),
2095 			DMI_MATCH(DMI_BOARD_NAME, "VT8367-8233A (KX7-333[R])"), },
2096 	},
2097 	{	/* APM crashes */
2098 		apm_is_horked, "Trigem Delhi3",
2099 		{	DMI_MATCH(DMI_SYS_VENDOR, "TriGem Computer, Inc"),
2100 			DMI_MATCH(DMI_PRODUCT_NAME, "Delhi3"), },
2101 	},
2102 	{	/* APM crashes */
2103 		apm_is_horked, "Fujitsu-Siemens",
2104 		{	DMI_MATCH(DMI_BIOS_VENDOR, "hoenix/FUJITSU SIEMENS"),
2105 			DMI_MATCH(DMI_BIOS_VERSION, "Version1.01"), },
2106 	},
2107 	{	/* APM crashes */
2108 		apm_is_horked_d850md, "Intel D850MD",
2109 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2110 			DMI_MATCH(DMI_BIOS_VERSION, "MV85010A.86A.0016.P07.0201251536"), },
2111 	},
2112 	{	/* APM crashes */
2113 		apm_is_horked, "Intel D810EMO",
2114 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2115 			DMI_MATCH(DMI_BIOS_VERSION, "MO81010A.86A.0008.P04.0004170800"), },
2116 	},
2117 	{	/* APM crashes */
2118 		apm_is_horked, "Dell XPS-Z",
2119 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2120 			DMI_MATCH(DMI_BIOS_VERSION, "A11"),
2121 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"), },
2122 	},
2123 	{	/* APM crashes */
2124 		apm_is_horked, "Sharp PC-PJ/AX",
2125 		{	DMI_MATCH(DMI_SYS_VENDOR, "SHARP"),
2126 			DMI_MATCH(DMI_PRODUCT_NAME, "PC-PJ/AX"),
2127 			DMI_MATCH(DMI_BIOS_VENDOR, "SystemSoft"),
2128 			DMI_MATCH(DMI_BIOS_VERSION, "Version R2.08"), },
2129 	},
2130 	{	/* APM crashes */
2131 		apm_is_horked, "Dell Inspiron 2500",
2132 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2133 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2134 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2135 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2136 	},
2137 	{	/* APM idle hangs */
2138 		apm_likes_to_melt, "Jabil AMD",
2139 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2140 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP06"), },
2141 	},
2142 	{	/* APM idle hangs */
2143 		apm_likes_to_melt, "AMI Bios",
2144 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2145 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP05"), },
2146 	},
2147 	{	/* Handle problems with APM on Sony Vaio PCG-N505X(DE) */
2148 		swab_apm_power_in_minutes, "Sony VAIO",
2149 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2150 			DMI_MATCH(DMI_BIOS_VERSION, "R0206H"),
2151 			DMI_MATCH(DMI_BIOS_DATE, "08/23/99"), },
2152 	},
2153 	{	/* Handle problems with APM on Sony Vaio PCG-N505VX */
2154 		swab_apm_power_in_minutes, "Sony VAIO",
2155 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2156 			DMI_MATCH(DMI_BIOS_VERSION, "W2K06H0"),
2157 			DMI_MATCH(DMI_BIOS_DATE, "02/03/00"), },
2158 	},
2159 	{	/* Handle problems with APM on Sony Vaio PCG-XG29 */
2160 		swab_apm_power_in_minutes, "Sony VAIO",
2161 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2162 			DMI_MATCH(DMI_BIOS_VERSION, "R0117A0"),
2163 			DMI_MATCH(DMI_BIOS_DATE, "04/25/00"), },
2164 	},
2165 	{	/* Handle problems with APM on Sony Vaio PCG-Z600NE */
2166 		swab_apm_power_in_minutes, "Sony VAIO",
2167 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2168 			DMI_MATCH(DMI_BIOS_VERSION, "R0121Z1"),
2169 			DMI_MATCH(DMI_BIOS_DATE, "05/11/00"), },
2170 	},
2171 	{	/* Handle problems with APM on Sony Vaio PCG-Z600NE */
2172 		swab_apm_power_in_minutes, "Sony VAIO",
2173 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2174 			DMI_MATCH(DMI_BIOS_VERSION, "WME01Z1"),
2175 			DMI_MATCH(DMI_BIOS_DATE, "08/11/00"), },
2176 	},
2177 	{	/* Handle problems with APM on Sony Vaio PCG-Z600LEK(DE) */
2178 		swab_apm_power_in_minutes, "Sony VAIO",
2179 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2180 			DMI_MATCH(DMI_BIOS_VERSION, "R0206Z3"),
2181 			DMI_MATCH(DMI_BIOS_DATE, "12/25/00"), },
2182 	},
2183 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS */
2184 		swab_apm_power_in_minutes, "Sony VAIO",
2185 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2186 			DMI_MATCH(DMI_BIOS_VERSION, "R0203D0"),
2187 			DMI_MATCH(DMI_BIOS_DATE, "05/12/00"), },
2188 	},
2189 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS */
2190 		swab_apm_power_in_minutes, "Sony VAIO",
2191 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2192 			DMI_MATCH(DMI_BIOS_VERSION, "R0203Z3"),
2193 			DMI_MATCH(DMI_BIOS_DATE, "08/25/00"), },
2194 	},
2195 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS (with updated BIOS) */
2196 		swab_apm_power_in_minutes, "Sony VAIO",
2197 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2198 			DMI_MATCH(DMI_BIOS_VERSION, "R0209Z3"),
2199 			DMI_MATCH(DMI_BIOS_DATE, "05/12/01"), },
2200 	},
2201 	{	/* Handle problems with APM on Sony Vaio PCG-F104K */
2202 		swab_apm_power_in_minutes, "Sony VAIO",
2203 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2204 			DMI_MATCH(DMI_BIOS_VERSION, "R0204K2"),
2205 			DMI_MATCH(DMI_BIOS_DATE, "08/28/00"), },
2206 	},
2207 
2208 	{	/* Handle problems with APM on Sony Vaio PCG-C1VN/C1VE */
2209 		swab_apm_power_in_minutes, "Sony VAIO",
2210 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2211 			DMI_MATCH(DMI_BIOS_VERSION, "R0208P1"),
2212 			DMI_MATCH(DMI_BIOS_DATE, "11/09/00"), },
2213 	},
2214 	{	/* Handle problems with APM on Sony Vaio PCG-C1VE */
2215 		swab_apm_power_in_minutes, "Sony VAIO",
2216 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2217 			DMI_MATCH(DMI_BIOS_VERSION, "R0204P1"),
2218 			DMI_MATCH(DMI_BIOS_DATE, "09/12/00"), },
2219 	},
2220 	{	/* Handle problems with APM on Sony Vaio PCG-C1VE */
2221 		swab_apm_power_in_minutes, "Sony VAIO",
2222 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2223 			DMI_MATCH(DMI_BIOS_VERSION, "WXPO1Z3"),
2224 			DMI_MATCH(DMI_BIOS_DATE, "10/26/01"), },
2225 	},
2226 	{	/* broken PM poweroff bios */
2227 		set_realmode_power_off, "Award Software v4.60 PGMA",
2228 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Award Software International, Inc."),
2229 			DMI_MATCH(DMI_BIOS_VERSION, "4.60 PGMA"),
2230 			DMI_MATCH(DMI_BIOS_DATE, "134526184"), },
2231 	},
2232 
2233 	/* Generic per vendor APM settings  */
2234 
2235 	{	/* Allow interrupts during suspend on IBM laptops */
2236 		set_apm_ints, "IBM",
2237 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"), },
2238 	},
2239 
2240 	{ }
2241 };
2242 
2243 /*
2244  * Just start the APM thread. We do NOT want to do APM BIOS
2245  * calls from anything but the APM thread, if for no other reason
2246  * than the fact that we don't trust the APM BIOS. This way,
2247  * most common APM BIOS problems that lead to protection errors
2248  * etc will have at least some level of being contained...
2249  *
2250  * In short, if something bad happens, at least we have a choice
2251  * of just killing the apm thread..
2252  */
2253 static int __init apm_init(void)
2254 {
2255 	struct desc_struct *gdt;
2256 	int err;
2257 
2258 	dmi_check_system(apm_dmi_table);
2259 
2260 	if (apm_info.bios.version == 0 || machine_is_olpc()) {
2261 		printk(KERN_INFO "apm: BIOS not found.\n");
2262 		return -ENODEV;
2263 	}
2264 	printk(KERN_INFO
2265 	       "apm: BIOS version %d.%d Flags 0x%02x (Driver version %s)\n",
2266 	       ((apm_info.bios.version >> 8) & 0xff),
2267 	       (apm_info.bios.version & 0xff),
2268 	       apm_info.bios.flags,
2269 	       driver_version);
2270 	if ((apm_info.bios.flags & APM_32_BIT_SUPPORT) == 0) {
2271 		printk(KERN_INFO "apm: no 32 bit BIOS support\n");
2272 		return -ENODEV;
2273 	}
2274 
2275 	if (allow_ints)
2276 		apm_info.allow_ints = 1;
2277 	if (broken_psr)
2278 		apm_info.get_power_status_broken = 1;
2279 	if (realmode_power_off)
2280 		apm_info.realmode_power_off = 1;
2281 	/* User can override, but default is to trust DMI */
2282 	if (apm_disabled != -1)
2283 		apm_info.disabled = apm_disabled;
2284 
2285 	/*
2286 	 * Fix for the Compaq Contura 3/25c which reports BIOS version 0.1
2287 	 * but is reportedly a 1.0 BIOS.
2288 	 */
2289 	if (apm_info.bios.version == 0x001)
2290 		apm_info.bios.version = 0x100;
2291 
2292 	/* BIOS < 1.2 doesn't set cseg_16_len */
2293 	if (apm_info.bios.version < 0x102)
2294 		apm_info.bios.cseg_16_len = 0; /* 64k */
2295 
2296 	if (debug) {
2297 		printk(KERN_INFO "apm: entry %x:%x cseg16 %x dseg %x",
2298 			apm_info.bios.cseg, apm_info.bios.offset,
2299 			apm_info.bios.cseg_16, apm_info.bios.dseg);
2300 		if (apm_info.bios.version > 0x100)
2301 			printk(" cseg len %x, dseg len %x",
2302 				apm_info.bios.cseg_len,
2303 				apm_info.bios.dseg_len);
2304 		if (apm_info.bios.version > 0x101)
2305 			printk(" cseg16 len %x", apm_info.bios.cseg_16_len);
2306 		printk("\n");
2307 	}
2308 
2309 	if (apm_info.disabled) {
2310 		pr_notice("disabled on user request.\n");
2311 		return -ENODEV;
2312 	}
2313 	if ((num_online_cpus() > 1) && !power_off && !smp) {
2314 		pr_notice("disabled - APM is not SMP safe.\n");
2315 		apm_info.disabled = 1;
2316 		return -ENODEV;
2317 	}
2318 	if (!acpi_disabled) {
2319 		pr_notice("overridden by ACPI.\n");
2320 		apm_info.disabled = 1;
2321 		return -ENODEV;
2322 	}
2323 
2324 	/*
2325 	 * Set up the long jump entry point to the APM BIOS, which is called
2326 	 * from inline assembly.
2327 	 */
2328 	apm_bios_entry.offset = apm_info.bios.offset;
2329 	apm_bios_entry.segment = APM_CS;
2330 
2331 	/*
2332 	 * The APM 1.1 BIOS is supposed to provide limit information that it
2333 	 * recognizes.  Many machines do this correctly, but many others do
2334 	 * not restrict themselves to their claimed limit.  When this happens,
2335 	 * they will cause a segmentation violation in the kernel at boot time.
2336 	 * Most BIOS's, however, will respect a 64k limit, so we use that.
2337 	 *
2338 	 * Note we only set APM segments on CPU zero, since we pin the APM
2339 	 * code to that CPU.
2340 	 */
2341 	gdt = get_cpu_gdt_rw(0);
2342 	set_desc_base(&gdt[APM_CS >> 3],
2343 		 (unsigned long)__va((unsigned long)apm_info.bios.cseg << 4));
2344 	set_desc_base(&gdt[APM_CS_16 >> 3],
2345 		 (unsigned long)__va((unsigned long)apm_info.bios.cseg_16 << 4));
2346 	set_desc_base(&gdt[APM_DS >> 3],
2347 		 (unsigned long)__va((unsigned long)apm_info.bios.dseg << 4));
2348 
2349 	proc_create_single("apm", 0, NULL, proc_apm_show);
2350 
2351 	kapmd_task = kthread_create(apm, NULL, "kapmd");
2352 	if (IS_ERR(kapmd_task)) {
2353 		pr_err("disabled - Unable to start kernel thread\n");
2354 		err = PTR_ERR(kapmd_task);
2355 		kapmd_task = NULL;
2356 		remove_proc_entry("apm", NULL);
2357 		return err;
2358 	}
2359 	wake_up_process(kapmd_task);
2360 
2361 	if (num_online_cpus() > 1 && !smp) {
2362 		printk(KERN_NOTICE
2363 		       "apm: disabled - APM is not SMP safe (power off active).\n");
2364 		return 0;
2365 	}
2366 
2367 	/*
2368 	 * Note we don't actually care if the misc_device cannot be registered.
2369 	 * this driver can do its job without it, even if userspace can't
2370 	 * control it.  just log the error
2371 	 */
2372 	if (misc_register(&apm_device))
2373 		printk(KERN_WARNING "apm: Could not register misc device.\n");
2374 
2375 	if (HZ != 100)
2376 		idle_period = (idle_period * HZ) / 100;
2377 	if (idle_threshold < 100) {
2378 		cpuidle_poll_state_init(&apm_idle_driver);
2379 		if (!cpuidle_register_driver(&apm_idle_driver))
2380 			if (cpuidle_register_device(&apm_cpuidle_device))
2381 				cpuidle_unregister_driver(&apm_idle_driver);
2382 	}
2383 
2384 	return 0;
2385 }
2386 
2387 static void __exit apm_exit(void)
2388 {
2389 	int error;
2390 
2391 	cpuidle_unregister_device(&apm_cpuidle_device);
2392 	cpuidle_unregister_driver(&apm_idle_driver);
2393 
2394 	if (((apm_info.bios.flags & APM_BIOS_DISENGAGED) == 0)
2395 	    && (apm_info.connection_version > 0x0100)) {
2396 		error = apm_engage_power_management(APM_DEVICE_ALL, 0);
2397 		if (error)
2398 			apm_error("disengage power management", error);
2399 	}
2400 	misc_deregister(&apm_device);
2401 	remove_proc_entry("apm", NULL);
2402 	if (power_off)
2403 		pm_power_off = NULL;
2404 	if (kapmd_task) {
2405 		kthread_stop(kapmd_task);
2406 		kapmd_task = NULL;
2407 	}
2408 }
2409 
2410 module_init(apm_init);
2411 module_exit(apm_exit);
2412 
2413 MODULE_AUTHOR("Stephen Rothwell");
2414 MODULE_DESCRIPTION("Advanced Power Management");
2415 MODULE_LICENSE("GPL");
2416 module_param(debug, bool, 0644);
2417 MODULE_PARM_DESC(debug, "Enable debug mode");
2418 module_param(power_off, bool, 0444);
2419 MODULE_PARM_DESC(power_off, "Enable power off");
2420 module_param(bounce_interval, int, 0444);
2421 MODULE_PARM_DESC(bounce_interval,
2422 		"Set the number of ticks to ignore suspend bounces");
2423 module_param(allow_ints, bool, 0444);
2424 MODULE_PARM_DESC(allow_ints, "Allow interrupts during BIOS calls");
2425 module_param(broken_psr, bool, 0444);
2426 MODULE_PARM_DESC(broken_psr, "BIOS has a broken GetPowerStatus call");
2427 module_param(realmode_power_off, bool, 0444);
2428 MODULE_PARM_DESC(realmode_power_off,
2429 		"Switch to real mode before powering off");
2430 module_param(idle_threshold, int, 0444);
2431 MODULE_PARM_DESC(idle_threshold,
2432 	"System idle percentage above which to make APM BIOS idle calls");
2433 module_param(idle_period, int, 0444);
2434 MODULE_PARM_DESC(idle_period,
2435 	"Period (in sec/100) over which to calculate the idle percentage");
2436 module_param(smp, bool, 0444);
2437 MODULE_PARM_DESC(smp,
2438 	"Set this to enable APM use on an SMP platform. Use with caution on older systems");
2439 MODULE_ALIAS_MISCDEV(APM_MINOR_DEV);
2440