xref: /openbmc/linux/arch/x86/kernel/apm_32.c (revision d9fd5a71)
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 inititialisation 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 
236 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
237 extern int (*console_blank_hook)(int);
238 #endif
239 
240 /*
241  * The apm_bios device is one of the misc char devices.
242  * This is its minor number.
243  */
244 #define	APM_MINOR_DEV	134
245 
246 /*
247  * Various options can be changed at boot time as follows:
248  * (We allow underscores for compatibility with the modules code)
249  *	apm=on/off			enable/disable APM
250  *	    [no-]allow[-_]ints		allow interrupts during BIOS calls
251  *	    [no-]broken[-_]psr		BIOS has a broken GetPowerStatus call
252  *	    [no-]realmode[-_]power[-_]off	switch to real mode before
253  *	    					powering off
254  *	    [no-]debug			log some debugging messages
255  *	    [no-]power[-_]off		power off on shutdown
256  *	    [no-]smp			Use apm even on an SMP box
257  *	    bounce[-_]interval=<n>	number of ticks to ignore suspend
258  *	    				bounces
259  *          idle[-_]threshold=<n>       System idle percentage above which to
260  *                                      make APM BIOS idle calls. Set it to
261  *                                      100 to disable.
262  *          idle[-_]period=<n>          Period (in 1/100s of a second) over
263  *                                      which the idle percentage is
264  *                                      calculated.
265  */
266 
267 /* KNOWN PROBLEM MACHINES:
268  *
269  * U: TI 4000M TravelMate: BIOS is *NOT* APM compliant
270  *                         [Confirmed by TI representative]
271  * ?: ACER 486DX4/75: uses dseg 0040, in violation of APM specification
272  *                    [Confirmed by BIOS disassembly]
273  *                    [This may work now ...]
274  * P: Toshiba 1950S: battery life information only gets updated after resume
275  * P: Midwest Micro Soundbook Elite DX2/66 monochrome: screen blanking
276  * 	broken in BIOS [Reported by Garst R. Reese <reese@isn.net>]
277  * ?: AcerNote-950: oops on reading /proc/apm - workaround is a WIP
278  * 	Neale Banks <neale@lowendale.com.au> December 2000
279  *
280  * Legend: U = unusable with APM patches
281  *         P = partially usable with APM patches
282  */
283 
284 /*
285  * Define as 1 to make the driver always call the APM BIOS busy
286  * routine even if the clock was not reported as slowed by the
287  * idle routine.  Otherwise, define as 0.
288  */
289 #define ALWAYS_CALL_BUSY   1
290 
291 /*
292  * Define to make the APM BIOS calls zero all data segment registers (so
293  * that an incorrect BIOS implementation will cause a kernel panic if it
294  * tries to write to arbitrary memory).
295  */
296 #define APM_ZERO_SEGS
297 
298 #include <asm/apm.h>
299 
300 /*
301  * Define to re-initialize the interrupt 0 timer to 100 Hz after a suspend.
302  * This patched by Chad Miller <cmiller@surfsouth.com>, original code by
303  * David Chen <chen@ctpa04.mit.edu>
304  */
305 #undef INIT_TIMER_AFTER_SUSPEND
306 
307 #ifdef INIT_TIMER_AFTER_SUSPEND
308 #include <linux/timex.h>
309 #include <asm/io.h>
310 #include <linux/delay.h>
311 #endif
312 
313 /*
314  * Need to poll the APM BIOS every second
315  */
316 #define APM_CHECK_TIMEOUT	(HZ)
317 
318 /*
319  * Ignore suspend events for this amount of time after a resume
320  */
321 #define DEFAULT_BOUNCE_INTERVAL	(3 * HZ)
322 
323 /*
324  * Maximum number of events stored
325  */
326 #define APM_MAX_EVENTS		20
327 
328 /*
329  * The per-file APM data
330  */
331 struct apm_user {
332 	int		magic;
333 	struct apm_user *next;
334 	unsigned int	suser: 1;
335 	unsigned int	writer: 1;
336 	unsigned int	reader: 1;
337 	unsigned int	suspend_wait: 1;
338 	int		suspend_result;
339 	int		suspends_pending;
340 	int		standbys_pending;
341 	int		suspends_read;
342 	int		standbys_read;
343 	int		event_head;
344 	int		event_tail;
345 	apm_event_t	events[APM_MAX_EVENTS];
346 };
347 
348 /*
349  * The magic number in apm_user
350  */
351 #define APM_BIOS_MAGIC		0x4101
352 
353 /*
354  * idle percentage above which bios idle calls are done
355  */
356 #ifdef CONFIG_APM_CPU_IDLE
357 #define DEFAULT_IDLE_THRESHOLD	95
358 #else
359 #define DEFAULT_IDLE_THRESHOLD	100
360 #endif
361 #define DEFAULT_IDLE_PERIOD	(100 / 3)
362 
363 static int apm_cpu_idle(struct cpuidle_device *dev,
364 			struct cpuidle_driver *drv, int index);
365 
366 static struct cpuidle_driver apm_idle_driver = {
367 	.name = "apm_idle",
368 	.owner = THIS_MODULE,
369 	.states = {
370 		{ /* entry 0 is for polling */ },
371 		{ /* entry 1 is for APM idle */
372 			.name = "APM",
373 			.desc = "APM idle",
374 			.exit_latency = 250,	/* WAG */
375 			.target_residency = 500,	/* WAG */
376 			.enter = &apm_cpu_idle
377 		},
378 	},
379 	.state_count = 2,
380 };
381 
382 static struct cpuidle_device apm_cpuidle_device;
383 
384 /*
385  * Local variables
386  */
387 __visible struct {
388 	unsigned long	offset;
389 	unsigned short	segment;
390 } apm_bios_entry;
391 static int clock_slowed;
392 static int idle_threshold __read_mostly = DEFAULT_IDLE_THRESHOLD;
393 static int idle_period __read_mostly = DEFAULT_IDLE_PERIOD;
394 static int suspends_pending;
395 static int standbys_pending;
396 static int ignore_sys_suspend;
397 static int ignore_normal_resume;
398 static int bounce_interval __read_mostly = DEFAULT_BOUNCE_INTERVAL;
399 
400 static bool debug __read_mostly;
401 static bool smp __read_mostly;
402 static int apm_disabled = -1;
403 #ifdef CONFIG_SMP
404 static bool power_off;
405 #else
406 static bool power_off = 1;
407 #endif
408 static bool realmode_power_off;
409 #ifdef CONFIG_APM_ALLOW_INTS
410 static bool allow_ints = 1;
411 #else
412 static bool allow_ints;
413 #endif
414 static bool broken_psr;
415 
416 static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
417 static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
418 static struct apm_user *user_list;
419 static DEFINE_SPINLOCK(user_list_lock);
420 static DEFINE_MUTEX(apm_mutex);
421 
422 /*
423  * Set up a segment that references the real mode segment 0x40
424  * that extends up to the end of page zero (that we have reserved).
425  * This is for buggy BIOS's that refer to (real mode) segment 0x40
426  * even though they are called in protected mode.
427  */
428 static struct desc_struct bad_bios_desc = GDT_ENTRY_INIT(0x4092,
429 			(unsigned long)__va(0x400UL), PAGE_SIZE - 0x400 - 1);
430 
431 static const char driver_version[] = "1.16ac";	/* no spaces */
432 
433 static struct task_struct *kapmd_task;
434 
435 /*
436  *	APM event names taken from the APM 1.2 specification. These are
437  *	the message codes that the BIOS uses to tell us about events
438  */
439 static const char * const apm_event_name[] = {
440 	"system standby",
441 	"system suspend",
442 	"normal resume",
443 	"critical resume",
444 	"low battery",
445 	"power status change",
446 	"update time",
447 	"critical suspend",
448 	"user standby",
449 	"user suspend",
450 	"system standby resume",
451 	"capabilities change"
452 };
453 #define NR_APM_EVENT_NAME ARRAY_SIZE(apm_event_name)
454 
455 typedef struct lookup_t {
456 	int	key;
457 	char 	*msg;
458 } lookup_t;
459 
460 /*
461  *	The BIOS returns a set of standard error codes in AX when the
462  *	carry flag is set.
463  */
464 
465 static const lookup_t error_table[] = {
466 /* N/A	{ APM_SUCCESS,		"Operation succeeded" }, */
467 	{ APM_DISABLED,		"Power management disabled" },
468 	{ APM_CONNECTED,	"Real mode interface already connected" },
469 	{ APM_NOT_CONNECTED,	"Interface not connected" },
470 	{ APM_16_CONNECTED,	"16 bit interface already connected" },
471 /* N/A	{ APM_16_UNSUPPORTED,	"16 bit interface not supported" }, */
472 	{ APM_32_CONNECTED,	"32 bit interface already connected" },
473 	{ APM_32_UNSUPPORTED,	"32 bit interface not supported" },
474 	{ APM_BAD_DEVICE,	"Unrecognized device ID" },
475 	{ APM_BAD_PARAM,	"Parameter out of range" },
476 	{ APM_NOT_ENGAGED,	"Interface not engaged" },
477 	{ APM_BAD_FUNCTION,     "Function not supported" },
478 	{ APM_RESUME_DISABLED,	"Resume timer disabled" },
479 	{ APM_BAD_STATE,	"Unable to enter requested state" },
480 /* N/A	{ APM_NO_EVENTS,	"No events pending" }, */
481 	{ APM_NO_ERROR,		"BIOS did not set a return code" },
482 	{ APM_NOT_PRESENT,	"No APM present" }
483 };
484 #define ERROR_COUNT	ARRAY_SIZE(error_table)
485 
486 /**
487  *	apm_error	-	display an APM error
488  *	@str: information string
489  *	@err: APM BIOS return code
490  *
491  *	Write a meaningful log entry to the kernel log in the event of
492  *	an APM error.  Note that this also handles (negative) kernel errors.
493  */
494 
495 static void apm_error(char *str, int err)
496 {
497 	int i;
498 
499 	for (i = 0; i < ERROR_COUNT; i++)
500 		if (error_table[i].key == err)
501 			break;
502 	if (i < ERROR_COUNT)
503 		pr_notice("%s: %s\n", str, error_table[i].msg);
504 	else if (err < 0)
505 		pr_notice("%s: linux error code %i\n", str, err);
506 	else
507 		pr_notice("%s: unknown error code %#2.2x\n",
508 		       str, err);
509 }
510 
511 /*
512  * These are the actual BIOS calls.  Depending on APM_ZERO_SEGS and
513  * apm_info.allow_ints, we are being really paranoid here!  Not only
514  * are interrupts disabled, but all the segment registers (except SS)
515  * are saved and zeroed this means that if the BIOS tries to reference
516  * any data without explicitly loading the segment registers, the kernel
517  * will fault immediately rather than have some unforeseen circumstances
518  * for the rest of the kernel.  And it will be very obvious!  :-) Doing
519  * this depends on CS referring to the same physical memory as DS so that
520  * DS can be zeroed before the call. Unfortunately, we can't do anything
521  * about the stack segment/pointer.  Also, we tell the compiler that
522  * everything could change.
523  *
524  * Also, we KNOW that for the non error case of apm_bios_call, there
525  * is no useful data returned in the low order 8 bits of eax.
526  */
527 
528 static inline unsigned long __apm_irq_save(void)
529 {
530 	unsigned long flags;
531 	local_save_flags(flags);
532 	if (apm_info.allow_ints) {
533 		if (irqs_disabled_flags(flags))
534 			local_irq_enable();
535 	} else
536 		local_irq_disable();
537 
538 	return flags;
539 }
540 
541 #define apm_irq_save(flags) \
542 	do { flags = __apm_irq_save(); } while (0)
543 
544 static inline void apm_irq_restore(unsigned long flags)
545 {
546 	if (irqs_disabled_flags(flags))
547 		local_irq_disable();
548 	else if (irqs_disabled())
549 		local_irq_enable();
550 }
551 
552 #ifdef APM_ZERO_SEGS
553 #	define APM_DECL_SEGS \
554 		unsigned int saved_fs; unsigned int saved_gs;
555 #	define APM_DO_SAVE_SEGS \
556 		savesegment(fs, saved_fs); savesegment(gs, saved_gs)
557 #	define APM_DO_RESTORE_SEGS \
558 		loadsegment(fs, saved_fs); loadsegment(gs, saved_gs)
559 #else
560 #	define APM_DECL_SEGS
561 #	define APM_DO_SAVE_SEGS
562 #	define APM_DO_RESTORE_SEGS
563 #endif
564 
565 struct apm_bios_call {
566 	u32 func;
567 	/* In and out */
568 	u32 ebx;
569 	u32 ecx;
570 	/* Out only */
571 	u32 eax;
572 	u32 edx;
573 	u32 esi;
574 
575 	/* Error: -ENOMEM, or bits 8-15 of eax */
576 	int err;
577 };
578 
579 /**
580  *	__apm_bios_call - Make an APM BIOS 32bit call
581  *	@_call: pointer to struct apm_bios_call.
582  *
583  *	Make an APM call using the 32bit protected mode interface. The
584  *	caller is responsible for knowing if APM BIOS is configured and
585  *	enabled. This call can disable interrupts for a long period of
586  *	time on some laptops.  The return value is in AH and the carry
587  *	flag is loaded into AL.  If there is an error, then the error
588  *	code is returned in AH (bits 8-15 of eax) and this function
589  *	returns non-zero.
590  *
591  *	Note: this makes the call on the current CPU.
592  */
593 static long __apm_bios_call(void *_call)
594 {
595 	APM_DECL_SEGS
596 	unsigned long		flags;
597 	int			cpu;
598 	struct desc_struct	save_desc_40;
599 	struct desc_struct	*gdt;
600 	struct apm_bios_call	*call = _call;
601 
602 	cpu = get_cpu();
603 	BUG_ON(cpu != 0);
604 	gdt = get_cpu_gdt_rw(cpu);
605 	save_desc_40 = gdt[0x40 / 8];
606 	gdt[0x40 / 8] = bad_bios_desc;
607 
608 	apm_irq_save(flags);
609 	firmware_restrict_branch_speculation_start();
610 	APM_DO_SAVE_SEGS;
611 	apm_bios_call_asm(call->func, call->ebx, call->ecx,
612 			  &call->eax, &call->ebx, &call->ecx, &call->edx,
613 			  &call->esi);
614 	APM_DO_RESTORE_SEGS;
615 	firmware_restrict_branch_speculation_end();
616 	apm_irq_restore(flags);
617 	gdt[0x40 / 8] = save_desc_40;
618 	put_cpu();
619 
620 	return call->eax & 0xff;
621 }
622 
623 /* Run __apm_bios_call or __apm_bios_call_simple on CPU 0 */
624 static int on_cpu0(long (*fn)(void *), struct apm_bios_call *call)
625 {
626 	int ret;
627 
628 	/* Don't bother with work_on_cpu in the common case, so we don't
629 	 * have to worry about OOM or overhead. */
630 	if (get_cpu() == 0) {
631 		ret = fn(call);
632 		put_cpu();
633 	} else {
634 		put_cpu();
635 		ret = work_on_cpu(0, fn, call);
636 	}
637 
638 	/* work_on_cpu can fail with -ENOMEM */
639 	if (ret < 0)
640 		call->err = ret;
641 	else
642 		call->err = (call->eax >> 8) & 0xff;
643 
644 	return ret;
645 }
646 
647 /**
648  *	apm_bios_call	-	Make an APM BIOS 32bit call (on CPU 0)
649  *	@call: the apm_bios_call registers.
650  *
651  *	If there is an error, it is returned in @call.err.
652  */
653 static int apm_bios_call(struct apm_bios_call *call)
654 {
655 	return on_cpu0(__apm_bios_call, call);
656 }
657 
658 /**
659  *	__apm_bios_call_simple - Make an APM BIOS 32bit call (on CPU 0)
660  *	@_call: pointer to struct apm_bios_call.
661  *
662  *	Make a BIOS call that returns one value only, or just status.
663  *	If there is an error, then the error code is returned in AH
664  *	(bits 8-15 of eax) and this function returns non-zero (it can
665  *	also return -ENOMEM). This is used for simpler BIOS operations.
666  *	This call may hold interrupts off for a long time on some laptops.
667  *
668  *	Note: this makes the call on the current CPU.
669  */
670 static long __apm_bios_call_simple(void *_call)
671 {
672 	u8			error;
673 	APM_DECL_SEGS
674 	unsigned long		flags;
675 	int			cpu;
676 	struct desc_struct	save_desc_40;
677 	struct desc_struct	*gdt;
678 	struct apm_bios_call	*call = _call;
679 
680 	cpu = get_cpu();
681 	BUG_ON(cpu != 0);
682 	gdt = get_cpu_gdt_rw(cpu);
683 	save_desc_40 = gdt[0x40 / 8];
684 	gdt[0x40 / 8] = bad_bios_desc;
685 
686 	apm_irq_save(flags);
687 	firmware_restrict_branch_speculation_start();
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 	firmware_restrict_branch_speculation_end();
693 	apm_irq_restore(flags);
694 	gdt[0x40 / 8] = save_desc_40;
695 	put_cpu();
696 	return error;
697 }
698 
699 /**
700  *	apm_bios_call_simple	-	make a simple APM BIOS 32bit call
701  *	@func: APM function to invoke
702  *	@ebx_in: EBX register value for BIOS call
703  *	@ecx_in: ECX register value for BIOS call
704  *	@eax: EAX register on return from the BIOS call
705  *	@err: bits
706  *
707  *	Make a BIOS call that returns one value only, or just status.
708  *	If there is an error, then the error code is returned in @err
709  *	and this function returns non-zero. This is used for simpler
710  *	BIOS operations.  This call may hold interrupts off for a long
711  *	time on some laptops.
712  */
713 static int apm_bios_call_simple(u32 func, u32 ebx_in, u32 ecx_in, u32 *eax,
714 				int *err)
715 {
716 	struct apm_bios_call call;
717 	int ret;
718 
719 	call.func = func;
720 	call.ebx = ebx_in;
721 	call.ecx = ecx_in;
722 
723 	ret = on_cpu0(__apm_bios_call_simple, &call);
724 	*eax = call.eax;
725 	*err = call.err;
726 	return ret;
727 }
728 
729 /**
730  *	apm_driver_version	-	APM driver version
731  *	@val:	loaded with the APM version on return
732  *
733  *	Retrieve the APM version supported by the BIOS. This is only
734  *	supported for APM 1.1 or higher. An error indicates APM 1.0 is
735  *	probably present.
736  *
737  *	On entry val should point to a value indicating the APM driver
738  *	version with the high byte being the major and the low byte the
739  *	minor number both in BCD
740  *
741  *	On return it will hold the BIOS revision supported in the
742  *	same format.
743  */
744 
745 static int apm_driver_version(u_short *val)
746 {
747 	u32 eax;
748 	int err;
749 
750 	if (apm_bios_call_simple(APM_FUNC_VERSION, 0, *val, &eax, &err))
751 		return err;
752 	*val = eax;
753 	return APM_SUCCESS;
754 }
755 
756 /**
757  *	apm_get_event	-	get an APM event from the BIOS
758  *	@event: pointer to the event
759  *	@info: point to the event information
760  *
761  *	The APM BIOS provides a polled information for event
762  *	reporting. The BIOS expects to be polled at least every second
763  *	when events are pending. When a message is found the caller should
764  *	poll until no more messages are present.  However, this causes
765  *	problems on some laptops where a suspend event notification is
766  *	not cleared until it is acknowledged.
767  *
768  *	Additional information is returned in the info pointer, providing
769  *	that APM 1.2 is in use. If no messges are pending the value 0x80
770  *	is returned (No power management events pending).
771  */
772 static int apm_get_event(apm_event_t *event, apm_eventinfo_t *info)
773 {
774 	struct apm_bios_call call;
775 
776 	call.func = APM_FUNC_GET_EVENT;
777 	call.ebx = call.ecx = 0;
778 
779 	if (apm_bios_call(&call))
780 		return call.err;
781 
782 	*event = call.ebx;
783 	if (apm_info.connection_version < 0x0102)
784 		*info = ~0; /* indicate info not valid */
785 	else
786 		*info = call.ecx;
787 	return APM_SUCCESS;
788 }
789 
790 /**
791  *	set_power_state	-	set the power management state
792  *	@what: which items to transition
793  *	@state: state to transition to
794  *
795  *	Request an APM change of state for one or more system devices. The
796  *	processor state must be transitioned last of all. what holds the
797  *	class of device in the upper byte and the device number (0xFF for
798  *	all) for the object to be transitioned.
799  *
800  *	The state holds the state to transition to, which may in fact
801  *	be an acceptance of a BIOS requested state change.
802  */
803 
804 static int set_power_state(u_short what, u_short state)
805 {
806 	u32 eax;
807 	int err;
808 
809 	if (apm_bios_call_simple(APM_FUNC_SET_STATE, what, state, &eax, &err))
810 		return err;
811 	return APM_SUCCESS;
812 }
813 
814 /**
815  *	set_system_power_state - set system wide power state
816  *	@state: which state to enter
817  *
818  *	Transition the entire system into a new APM power state.
819  */
820 
821 static int set_system_power_state(u_short state)
822 {
823 	return set_power_state(APM_DEVICE_ALL, state);
824 }
825 
826 /**
827  *	apm_do_idle	-	perform power saving
828  *
829  *	This function notifies the BIOS that the processor is (in the view
830  *	of the OS) idle. It returns -1 in the event that the BIOS refuses
831  *	to handle the idle request. On a success the function returns 1
832  *	if the BIOS did clock slowing or 0 otherwise.
833  */
834 
835 static int apm_do_idle(void)
836 {
837 	u32 eax;
838 	u8 ret = 0;
839 	int idled = 0;
840 	int err = 0;
841 
842 	if (!need_resched()) {
843 		idled = 1;
844 		ret = apm_bios_call_simple(APM_FUNC_IDLE, 0, 0, &eax, &err);
845 	}
846 
847 	if (!idled)
848 		return 0;
849 
850 	if (ret) {
851 		static unsigned long t;
852 
853 		/* This always fails on some SMP boards running UP kernels.
854 		 * Only report the failure the first 5 times.
855 		 */
856 		if (++t < 5) {
857 			printk(KERN_DEBUG "apm_do_idle failed (%d)\n", err);
858 			t = jiffies;
859 		}
860 		return -1;
861 	}
862 	clock_slowed = (apm_info.bios.flags & APM_IDLE_SLOWS_CLOCK) != 0;
863 	return clock_slowed;
864 }
865 
866 /**
867  *	apm_do_busy	-	inform the BIOS the CPU is busy
868  *
869  *	Request that the BIOS brings the CPU back to full performance.
870  */
871 
872 static void apm_do_busy(void)
873 {
874 	u32 dummy;
875 	int err;
876 
877 	if (clock_slowed || ALWAYS_CALL_BUSY) {
878 		(void)apm_bios_call_simple(APM_FUNC_BUSY, 0, 0, &dummy, &err);
879 		clock_slowed = 0;
880 	}
881 }
882 
883 /*
884  * If no process has really been interested in
885  * the CPU for some time, we want to call BIOS
886  * power management - we probably want
887  * to conserve power.
888  */
889 #define IDLE_CALC_LIMIT	(HZ * 100)
890 #define IDLE_LEAKY_MAX	16
891 
892 /**
893  * apm_cpu_idle		-	cpu idling for APM capable Linux
894  *
895  * This is the idling function the kernel executes when APM is available. It
896  * tries to do BIOS powermanagement based on the average system idle time.
897  * Furthermore it calls the system default idle routine.
898  */
899 
900 static int apm_cpu_idle(struct cpuidle_device *dev,
901 	struct cpuidle_driver *drv, int index)
902 {
903 	static int use_apm_idle; /* = 0 */
904 	static unsigned int last_jiffies; /* = 0 */
905 	static u64 last_stime; /* = 0 */
906 	u64 stime, utime;
907 
908 	int apm_idle_done = 0;
909 	unsigned int jiffies_since_last_check = jiffies - last_jiffies;
910 	unsigned int bucket;
911 
912 recalc:
913 	task_cputime(current, &utime, &stime);
914 	if (jiffies_since_last_check > IDLE_CALC_LIMIT) {
915 		use_apm_idle = 0;
916 	} else if (jiffies_since_last_check > idle_period) {
917 		unsigned int idle_percentage;
918 
919 		idle_percentage = nsecs_to_jiffies(stime - last_stime);
920 		idle_percentage *= 100;
921 		idle_percentage /= jiffies_since_last_check;
922 		use_apm_idle = (idle_percentage > idle_threshold);
923 		if (apm_info.forbid_idle)
924 			use_apm_idle = 0;
925 	}
926 
927 	last_jiffies = jiffies;
928 	last_stime = stime;
929 
930 	bucket = IDLE_LEAKY_MAX;
931 
932 	while (!need_resched()) {
933 		if (use_apm_idle) {
934 			unsigned int t;
935 
936 			t = jiffies;
937 			switch (apm_do_idle()) {
938 			case 0:
939 				apm_idle_done = 1;
940 				if (t != jiffies) {
941 					if (bucket) {
942 						bucket = IDLE_LEAKY_MAX;
943 						continue;
944 					}
945 				} else if (bucket) {
946 					bucket--;
947 					continue;
948 				}
949 				break;
950 			case 1:
951 				apm_idle_done = 1;
952 				break;
953 			default: /* BIOS refused */
954 				break;
955 			}
956 		}
957 		default_idle();
958 		local_irq_disable();
959 		jiffies_since_last_check = jiffies - last_jiffies;
960 		if (jiffies_since_last_check > idle_period)
961 			goto recalc;
962 	}
963 
964 	if (apm_idle_done)
965 		apm_do_busy();
966 
967 	return index;
968 }
969 
970 /**
971  *	apm_power_off	-	ask the BIOS to power off
972  *
973  *	Handle the power off sequence. This is the one piece of code we
974  *	will execute even on SMP machines. In order to deal with BIOS
975  *	bugs we support real mode APM BIOS power off calls. We also make
976  *	the SMP call on CPU0 as some systems will only honour this call
977  *	on their first cpu.
978  */
979 
980 static void apm_power_off(void)
981 {
982 	/* Some bioses don't like being called from CPU != 0 */
983 	if (apm_info.realmode_power_off) {
984 		set_cpus_allowed_ptr(current, cpumask_of(0));
985 		machine_real_restart(MRR_APM);
986 	} else {
987 		(void)set_system_power_state(APM_STATE_OFF);
988 	}
989 }
990 
991 #ifdef CONFIG_APM_DO_ENABLE
992 
993 /**
994  *	apm_enable_power_management - enable BIOS APM power management
995  *	@enable: enable yes/no
996  *
997  *	Enable or disable the APM BIOS power services.
998  */
999 
1000 static int apm_enable_power_management(int enable)
1001 {
1002 	u32 eax;
1003 	int err;
1004 
1005 	if ((enable == 0) && (apm_info.bios.flags & APM_BIOS_DISENGAGED))
1006 		return APM_NOT_ENGAGED;
1007 	if (apm_bios_call_simple(APM_FUNC_ENABLE_PM, APM_DEVICE_BALL,
1008 				 enable, &eax, &err))
1009 		return err;
1010 	if (enable)
1011 		apm_info.bios.flags &= ~APM_BIOS_DISABLED;
1012 	else
1013 		apm_info.bios.flags |= APM_BIOS_DISABLED;
1014 	return APM_SUCCESS;
1015 }
1016 #endif
1017 
1018 /**
1019  *	apm_get_power_status	-	get current power state
1020  *	@status: returned status
1021  *	@bat: battery info
1022  *	@life: estimated life
1023  *
1024  *	Obtain the current power status from the APM BIOS. We return a
1025  *	status which gives the rough battery status, and current power
1026  *	source. The bat value returned give an estimate as a percentage
1027  *	of life and a status value for the battery. The estimated life
1028  *	if reported is a lifetime in secodnds/minutes at current powwer
1029  *	consumption.
1030  */
1031 
1032 static int apm_get_power_status(u_short *status, u_short *bat, u_short *life)
1033 {
1034 	struct apm_bios_call call;
1035 
1036 	call.func = APM_FUNC_GET_STATUS;
1037 	call.ebx = APM_DEVICE_ALL;
1038 	call.ecx = 0;
1039 
1040 	if (apm_info.get_power_status_broken)
1041 		return APM_32_UNSUPPORTED;
1042 	if (apm_bios_call(&call)) {
1043 		if (!call.err)
1044 			return APM_NO_ERROR;
1045 		return call.err;
1046 	}
1047 	*status = call.ebx;
1048 	*bat = call.ecx;
1049 	if (apm_info.get_power_status_swabinminutes) {
1050 		*life = swab16((u16)call.edx);
1051 		*life |= 0x8000;
1052 	} else
1053 		*life = call.edx;
1054 	return APM_SUCCESS;
1055 }
1056 
1057 #if 0
1058 static int apm_get_battery_status(u_short which, u_short *status,
1059 				  u_short *bat, u_short *life, u_short *nbat)
1060 {
1061 	u32 eax;
1062 	u32 ebx;
1063 	u32 ecx;
1064 	u32 edx;
1065 	u32 esi;
1066 
1067 	if (apm_info.connection_version < 0x0102) {
1068 		/* pretend we only have one battery. */
1069 		if (which != 1)
1070 			return APM_BAD_DEVICE;
1071 		*nbat = 1;
1072 		return apm_get_power_status(status, bat, life);
1073 	}
1074 
1075 	if (apm_bios_call(APM_FUNC_GET_STATUS, (0x8000 | (which)), 0, &eax,
1076 			  &ebx, &ecx, &edx, &esi))
1077 		return (eax >> 8) & 0xff;
1078 	*status = ebx;
1079 	*bat = ecx;
1080 	*life = edx;
1081 	*nbat = esi;
1082 	return APM_SUCCESS;
1083 }
1084 #endif
1085 
1086 /**
1087  *	apm_engage_power_management	-	enable PM on a device
1088  *	@device: identity of device
1089  *	@enable: on/off
1090  *
1091  *	Activate or deactivate power management on either a specific device
1092  *	or the entire system (%APM_DEVICE_ALL).
1093  */
1094 
1095 static int apm_engage_power_management(u_short device, int enable)
1096 {
1097 	u32 eax;
1098 	int err;
1099 
1100 	if ((enable == 0) && (device == APM_DEVICE_ALL)
1101 	    && (apm_info.bios.flags & APM_BIOS_DISABLED))
1102 		return APM_DISABLED;
1103 	if (apm_bios_call_simple(APM_FUNC_ENGAGE_PM, device, enable,
1104 				 &eax, &err))
1105 		return err;
1106 	if (device == APM_DEVICE_ALL) {
1107 		if (enable)
1108 			apm_info.bios.flags &= ~APM_BIOS_DISENGAGED;
1109 		else
1110 			apm_info.bios.flags |= APM_BIOS_DISENGAGED;
1111 	}
1112 	return APM_SUCCESS;
1113 }
1114 
1115 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1116 
1117 /**
1118  *	apm_console_blank	-	blank the display
1119  *	@blank: on/off
1120  *
1121  *	Attempt to blank the console, firstly by blanking just video device
1122  *	zero, and if that fails (some BIOSes don't support it) then it blanks
1123  *	all video devices. Typically the BIOS will do laptop backlight and
1124  *	monitor powerdown for us.
1125  */
1126 
1127 static int apm_console_blank(int blank)
1128 {
1129 	int error = APM_NOT_ENGAGED; /* silence gcc */
1130 	int i;
1131 	u_short state;
1132 	static const u_short dev[3] = { 0x100, 0x1FF, 0x101 };
1133 
1134 	state = blank ? APM_STATE_STANDBY : APM_STATE_READY;
1135 
1136 	for (i = 0; i < ARRAY_SIZE(dev); i++) {
1137 		error = set_power_state(dev[i], state);
1138 
1139 		if ((error == APM_SUCCESS) || (error == APM_NO_ERROR))
1140 			return 1;
1141 
1142 		if (error == APM_NOT_ENGAGED)
1143 			break;
1144 	}
1145 
1146 	if (error == APM_NOT_ENGAGED) {
1147 		static int tried;
1148 		int eng_error;
1149 		if (tried++ == 0) {
1150 			eng_error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1151 			if (eng_error) {
1152 				apm_error("set display", error);
1153 				apm_error("engage interface", eng_error);
1154 				return 0;
1155 			} else
1156 				return apm_console_blank(blank);
1157 		}
1158 	}
1159 	apm_error("set display", error);
1160 	return 0;
1161 }
1162 #endif
1163 
1164 static int queue_empty(struct apm_user *as)
1165 {
1166 	return as->event_head == as->event_tail;
1167 }
1168 
1169 static apm_event_t get_queued_event(struct apm_user *as)
1170 {
1171 	if (++as->event_tail >= APM_MAX_EVENTS)
1172 		as->event_tail = 0;
1173 	return as->events[as->event_tail];
1174 }
1175 
1176 static void queue_event(apm_event_t event, struct apm_user *sender)
1177 {
1178 	struct apm_user *as;
1179 
1180 	spin_lock(&user_list_lock);
1181 	if (user_list == NULL)
1182 		goto out;
1183 	for (as = user_list; as != NULL; as = as->next) {
1184 		if ((as == sender) || (!as->reader))
1185 			continue;
1186 		if (++as->event_head >= APM_MAX_EVENTS)
1187 			as->event_head = 0;
1188 
1189 		if (as->event_head == as->event_tail) {
1190 			static int notified;
1191 
1192 			if (notified++ == 0)
1193 				pr_err("an event queue overflowed\n");
1194 			if (++as->event_tail >= APM_MAX_EVENTS)
1195 				as->event_tail = 0;
1196 		}
1197 		as->events[as->event_head] = event;
1198 		if (!as->suser || !as->writer)
1199 			continue;
1200 		switch (event) {
1201 		case APM_SYS_SUSPEND:
1202 		case APM_USER_SUSPEND:
1203 			as->suspends_pending++;
1204 			suspends_pending++;
1205 			break;
1206 
1207 		case APM_SYS_STANDBY:
1208 		case APM_USER_STANDBY:
1209 			as->standbys_pending++;
1210 			standbys_pending++;
1211 			break;
1212 		}
1213 	}
1214 	wake_up_interruptible(&apm_waitqueue);
1215 out:
1216 	spin_unlock(&user_list_lock);
1217 }
1218 
1219 static void reinit_timer(void)
1220 {
1221 #ifdef INIT_TIMER_AFTER_SUSPEND
1222 	unsigned long flags;
1223 
1224 	raw_spin_lock_irqsave(&i8253_lock, flags);
1225 	/* set the clock to HZ */
1226 	outb_p(0x34, PIT_MODE);		/* binary, mode 2, LSB/MSB, ch 0 */
1227 	udelay(10);
1228 	outb_p(LATCH & 0xff, PIT_CH0);	/* LSB */
1229 	udelay(10);
1230 	outb_p(LATCH >> 8, PIT_CH0);	/* MSB */
1231 	udelay(10);
1232 	raw_spin_unlock_irqrestore(&i8253_lock, flags);
1233 #endif
1234 }
1235 
1236 static int suspend(int vetoable)
1237 {
1238 	int err;
1239 	struct apm_user	*as;
1240 
1241 	dpm_suspend_start(PMSG_SUSPEND);
1242 	dpm_suspend_end(PMSG_SUSPEND);
1243 
1244 	local_irq_disable();
1245 	syscore_suspend();
1246 
1247 	local_irq_enable();
1248 
1249 	save_processor_state();
1250 	err = set_system_power_state(APM_STATE_SUSPEND);
1251 	ignore_normal_resume = 1;
1252 	restore_processor_state();
1253 
1254 	local_irq_disable();
1255 	reinit_timer();
1256 
1257 	if (err == APM_NO_ERROR)
1258 		err = APM_SUCCESS;
1259 	if (err != APM_SUCCESS)
1260 		apm_error("suspend", err);
1261 	err = (err == APM_SUCCESS) ? 0 : -EIO;
1262 
1263 	syscore_resume();
1264 	local_irq_enable();
1265 
1266 	dpm_resume_start(PMSG_RESUME);
1267 	dpm_resume_end(PMSG_RESUME);
1268 
1269 	queue_event(APM_NORMAL_RESUME, NULL);
1270 	spin_lock(&user_list_lock);
1271 	for (as = user_list; as != NULL; as = as->next) {
1272 		as->suspend_wait = 0;
1273 		as->suspend_result = err;
1274 	}
1275 	spin_unlock(&user_list_lock);
1276 	wake_up_interruptible(&apm_suspend_waitqueue);
1277 	return err;
1278 }
1279 
1280 static void standby(void)
1281 {
1282 	int err;
1283 
1284 	dpm_suspend_end(PMSG_SUSPEND);
1285 
1286 	local_irq_disable();
1287 	syscore_suspend();
1288 	local_irq_enable();
1289 
1290 	err = set_system_power_state(APM_STATE_STANDBY);
1291 	if ((err != APM_SUCCESS) && (err != APM_NO_ERROR))
1292 		apm_error("standby", err);
1293 
1294 	local_irq_disable();
1295 	syscore_resume();
1296 	local_irq_enable();
1297 
1298 	dpm_resume_start(PMSG_RESUME);
1299 }
1300 
1301 static apm_event_t get_event(void)
1302 {
1303 	int error;
1304 	apm_event_t event = APM_NO_EVENTS; /* silence gcc */
1305 	apm_eventinfo_t	info;
1306 
1307 	static int notified;
1308 
1309 	/* we don't use the eventinfo */
1310 	error = apm_get_event(&event, &info);
1311 	if (error == APM_SUCCESS)
1312 		return event;
1313 
1314 	if ((error != APM_NO_EVENTS) && (notified++ == 0))
1315 		apm_error("get_event", error);
1316 
1317 	return 0;
1318 }
1319 
1320 static void check_events(void)
1321 {
1322 	apm_event_t event;
1323 	static unsigned long last_resume;
1324 	static int ignore_bounce;
1325 
1326 	while ((event = get_event()) != 0) {
1327 		if (debug) {
1328 			if (event <= NR_APM_EVENT_NAME)
1329 				printk(KERN_DEBUG "apm: received %s notify\n",
1330 				       apm_event_name[event - 1]);
1331 			else
1332 				printk(KERN_DEBUG "apm: received unknown "
1333 				       "event 0x%02x\n", event);
1334 		}
1335 		if (ignore_bounce
1336 		    && (time_after(jiffies, last_resume + bounce_interval)))
1337 			ignore_bounce = 0;
1338 
1339 		switch (event) {
1340 		case APM_SYS_STANDBY:
1341 		case APM_USER_STANDBY:
1342 			queue_event(event, NULL);
1343 			if (standbys_pending <= 0)
1344 				standby();
1345 			break;
1346 
1347 		case APM_USER_SUSPEND:
1348 #ifdef CONFIG_APM_IGNORE_USER_SUSPEND
1349 			if (apm_info.connection_version > 0x100)
1350 				set_system_power_state(APM_STATE_REJECT);
1351 			break;
1352 #endif
1353 		case APM_SYS_SUSPEND:
1354 			if (ignore_bounce) {
1355 				if (apm_info.connection_version > 0x100)
1356 					set_system_power_state(APM_STATE_REJECT);
1357 				break;
1358 			}
1359 			/*
1360 			 * If we are already processing a SUSPEND,
1361 			 * then further SUSPEND events from the BIOS
1362 			 * will be ignored.  We also return here to
1363 			 * cope with the fact that the Thinkpads keep
1364 			 * sending a SUSPEND event until something else
1365 			 * happens!
1366 			 */
1367 			if (ignore_sys_suspend)
1368 				return;
1369 			ignore_sys_suspend = 1;
1370 			queue_event(event, NULL);
1371 			if (suspends_pending <= 0)
1372 				(void) suspend(1);
1373 			break;
1374 
1375 		case APM_NORMAL_RESUME:
1376 		case APM_CRITICAL_RESUME:
1377 		case APM_STANDBY_RESUME:
1378 			ignore_sys_suspend = 0;
1379 			last_resume = jiffies;
1380 			ignore_bounce = 1;
1381 			if ((event != APM_NORMAL_RESUME)
1382 			    || (ignore_normal_resume == 0)) {
1383 				dpm_resume_end(PMSG_RESUME);
1384 				queue_event(event, NULL);
1385 			}
1386 			ignore_normal_resume = 0;
1387 			break;
1388 
1389 		case APM_CAPABILITY_CHANGE:
1390 		case APM_LOW_BATTERY:
1391 		case APM_POWER_STATUS_CHANGE:
1392 			queue_event(event, NULL);
1393 			/* If needed, notify drivers here */
1394 			break;
1395 
1396 		case APM_UPDATE_TIME:
1397 			break;
1398 
1399 		case APM_CRITICAL_SUSPEND:
1400 			/*
1401 			 * We are not allowed to reject a critical suspend.
1402 			 */
1403 			(void)suspend(0);
1404 			break;
1405 		}
1406 	}
1407 }
1408 
1409 static void apm_event_handler(void)
1410 {
1411 	static int pending_count = 4;
1412 	int err;
1413 
1414 	if ((standbys_pending > 0) || (suspends_pending > 0)) {
1415 		if ((apm_info.connection_version > 0x100) &&
1416 		    (pending_count-- <= 0)) {
1417 			pending_count = 4;
1418 			if (debug)
1419 				printk(KERN_DEBUG "apm: setting state busy\n");
1420 			err = set_system_power_state(APM_STATE_BUSY);
1421 			if (err)
1422 				apm_error("busy", err);
1423 		}
1424 	} else
1425 		pending_count = 4;
1426 	check_events();
1427 }
1428 
1429 /*
1430  * This is the APM thread main loop.
1431  */
1432 
1433 static void apm_mainloop(void)
1434 {
1435 	DECLARE_WAITQUEUE(wait, current);
1436 
1437 	add_wait_queue(&apm_waitqueue, &wait);
1438 	set_current_state(TASK_INTERRUPTIBLE);
1439 	for (;;) {
1440 		schedule_timeout(APM_CHECK_TIMEOUT);
1441 		if (kthread_should_stop())
1442 			break;
1443 		/*
1444 		 * Ok, check all events, check for idle (and mark us sleeping
1445 		 * so as not to count towards the load average)..
1446 		 */
1447 		set_current_state(TASK_INTERRUPTIBLE);
1448 		apm_event_handler();
1449 	}
1450 	remove_wait_queue(&apm_waitqueue, &wait);
1451 }
1452 
1453 static int check_apm_user(struct apm_user *as, const char *func)
1454 {
1455 	if (as == NULL || as->magic != APM_BIOS_MAGIC) {
1456 		pr_err("%s passed bad filp\n", func);
1457 		return 1;
1458 	}
1459 	return 0;
1460 }
1461 
1462 static ssize_t do_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
1463 {
1464 	struct apm_user *as;
1465 	int i;
1466 	apm_event_t event;
1467 
1468 	as = fp->private_data;
1469 	if (check_apm_user(as, "read"))
1470 		return -EIO;
1471 	if ((int)count < sizeof(apm_event_t))
1472 		return -EINVAL;
1473 	if ((queue_empty(as)) && (fp->f_flags & O_NONBLOCK))
1474 		return -EAGAIN;
1475 	wait_event_interruptible(apm_waitqueue, !queue_empty(as));
1476 	i = count;
1477 	while ((i >= sizeof(event)) && !queue_empty(as)) {
1478 		event = get_queued_event(as);
1479 		if (copy_to_user(buf, &event, sizeof(event))) {
1480 			if (i < count)
1481 				break;
1482 			return -EFAULT;
1483 		}
1484 		switch (event) {
1485 		case APM_SYS_SUSPEND:
1486 		case APM_USER_SUSPEND:
1487 			as->suspends_read++;
1488 			break;
1489 
1490 		case APM_SYS_STANDBY:
1491 		case APM_USER_STANDBY:
1492 			as->standbys_read++;
1493 			break;
1494 		}
1495 		buf += sizeof(event);
1496 		i -= sizeof(event);
1497 	}
1498 	if (i < count)
1499 		return count - i;
1500 	if (signal_pending(current))
1501 		return -ERESTARTSYS;
1502 	return 0;
1503 }
1504 
1505 static __poll_t do_poll(struct file *fp, poll_table *wait)
1506 {
1507 	struct apm_user *as;
1508 
1509 	as = fp->private_data;
1510 	if (check_apm_user(as, "poll"))
1511 		return 0;
1512 	poll_wait(fp, &apm_waitqueue, wait);
1513 	if (!queue_empty(as))
1514 		return EPOLLIN | EPOLLRDNORM;
1515 	return 0;
1516 }
1517 
1518 static long do_ioctl(struct file *filp, u_int cmd, u_long arg)
1519 {
1520 	struct apm_user *as;
1521 	int ret;
1522 
1523 	as = filp->private_data;
1524 	if (check_apm_user(as, "ioctl"))
1525 		return -EIO;
1526 	if (!as->suser || !as->writer)
1527 		return -EPERM;
1528 	switch (cmd) {
1529 	case APM_IOC_STANDBY:
1530 		mutex_lock(&apm_mutex);
1531 		if (as->standbys_read > 0) {
1532 			as->standbys_read--;
1533 			as->standbys_pending--;
1534 			standbys_pending--;
1535 		} else
1536 			queue_event(APM_USER_STANDBY, as);
1537 		if (standbys_pending <= 0)
1538 			standby();
1539 		mutex_unlock(&apm_mutex);
1540 		break;
1541 	case APM_IOC_SUSPEND:
1542 		mutex_lock(&apm_mutex);
1543 		if (as->suspends_read > 0) {
1544 			as->suspends_read--;
1545 			as->suspends_pending--;
1546 			suspends_pending--;
1547 		} else
1548 			queue_event(APM_USER_SUSPEND, as);
1549 		if (suspends_pending <= 0) {
1550 			ret = suspend(1);
1551 			mutex_unlock(&apm_mutex);
1552 		} else {
1553 			as->suspend_wait = 1;
1554 			mutex_unlock(&apm_mutex);
1555 			wait_event_interruptible(apm_suspend_waitqueue,
1556 					as->suspend_wait == 0);
1557 			ret = as->suspend_result;
1558 		}
1559 		return ret;
1560 	default:
1561 		return -ENOTTY;
1562 	}
1563 	return 0;
1564 }
1565 
1566 static int do_release(struct inode *inode, struct file *filp)
1567 {
1568 	struct apm_user *as;
1569 
1570 	as = filp->private_data;
1571 	if (check_apm_user(as, "release"))
1572 		return 0;
1573 	filp->private_data = NULL;
1574 	if (as->standbys_pending > 0) {
1575 		standbys_pending -= as->standbys_pending;
1576 		if (standbys_pending <= 0)
1577 			standby();
1578 	}
1579 	if (as->suspends_pending > 0) {
1580 		suspends_pending -= as->suspends_pending;
1581 		if (suspends_pending <= 0)
1582 			(void) suspend(1);
1583 	}
1584 	spin_lock(&user_list_lock);
1585 	if (user_list == as)
1586 		user_list = as->next;
1587 	else {
1588 		struct apm_user *as1;
1589 
1590 		for (as1 = user_list;
1591 		     (as1 != NULL) && (as1->next != as);
1592 		     as1 = as1->next)
1593 			;
1594 		if (as1 == NULL)
1595 			pr_err("filp not in user list\n");
1596 		else
1597 			as1->next = as->next;
1598 	}
1599 	spin_unlock(&user_list_lock);
1600 	kfree(as);
1601 	return 0;
1602 }
1603 
1604 static int do_open(struct inode *inode, struct file *filp)
1605 {
1606 	struct apm_user *as;
1607 
1608 	as = kmalloc(sizeof(*as), GFP_KERNEL);
1609 	if (as == NULL)
1610 		return -ENOMEM;
1611 
1612 	as->magic = APM_BIOS_MAGIC;
1613 	as->event_tail = as->event_head = 0;
1614 	as->suspends_pending = as->standbys_pending = 0;
1615 	as->suspends_read = as->standbys_read = 0;
1616 	/*
1617 	 * XXX - this is a tiny bit broken, when we consider BSD
1618 	 * process accounting. If the device is opened by root, we
1619 	 * instantly flag that we used superuser privs. Who knows,
1620 	 * we might close the device immediately without doing a
1621 	 * privileged operation -- cevans
1622 	 */
1623 	as->suser = capable(CAP_SYS_ADMIN);
1624 	as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
1625 	as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
1626 	spin_lock(&user_list_lock);
1627 	as->next = user_list;
1628 	user_list = as;
1629 	spin_unlock(&user_list_lock);
1630 	filp->private_data = as;
1631 	return 0;
1632 }
1633 
1634 #ifdef CONFIG_PROC_FS
1635 static int proc_apm_show(struct seq_file *m, void *v)
1636 {
1637 	unsigned short	bx;
1638 	unsigned short	cx;
1639 	unsigned short	dx;
1640 	int		error;
1641 	unsigned short  ac_line_status = 0xff;
1642 	unsigned short  battery_status = 0xff;
1643 	unsigned short  battery_flag   = 0xff;
1644 	int		percentage     = -1;
1645 	int             time_units     = -1;
1646 	char            *units         = "?";
1647 
1648 	if ((num_online_cpus() == 1) &&
1649 	    !(error = apm_get_power_status(&bx, &cx, &dx))) {
1650 		ac_line_status = (bx >> 8) & 0xff;
1651 		battery_status = bx & 0xff;
1652 		if ((cx & 0xff) != 0xff)
1653 			percentage = cx & 0xff;
1654 
1655 		if (apm_info.connection_version > 0x100) {
1656 			battery_flag = (cx >> 8) & 0xff;
1657 			if (dx != 0xffff) {
1658 				units = (dx & 0x8000) ? "min" : "sec";
1659 				time_units = dx & 0x7fff;
1660 			}
1661 		}
1662 	}
1663 	/* Arguments, with symbols from linux/apm_bios.h.  Information is
1664 	   from the Get Power Status (0x0a) call unless otherwise noted.
1665 
1666 	   0) Linux driver version (this will change if format changes)
1667 	   1) APM BIOS Version.  Usually 1.0, 1.1 or 1.2.
1668 	   2) APM flags from APM Installation Check (0x00):
1669 	      bit 0: APM_16_BIT_SUPPORT
1670 	      bit 1: APM_32_BIT_SUPPORT
1671 	      bit 2: APM_IDLE_SLOWS_CLOCK
1672 	      bit 3: APM_BIOS_DISABLED
1673 	      bit 4: APM_BIOS_DISENGAGED
1674 	   3) AC line status
1675 	      0x00: Off-line
1676 	      0x01: On-line
1677 	      0x02: On backup power (BIOS >= 1.1 only)
1678 	      0xff: Unknown
1679 	   4) Battery status
1680 	      0x00: High
1681 	      0x01: Low
1682 	      0x02: Critical
1683 	      0x03: Charging
1684 	      0x04: Selected battery not present (BIOS >= 1.2 only)
1685 	      0xff: Unknown
1686 	   5) Battery flag
1687 	      bit 0: High
1688 	      bit 1: Low
1689 	      bit 2: Critical
1690 	      bit 3: Charging
1691 	      bit 7: No system battery
1692 	      0xff: Unknown
1693 	   6) Remaining battery life (percentage of charge):
1694 	      0-100: valid
1695 	      -1: Unknown
1696 	   7) Remaining battery life (time units):
1697 	      Number of remaining minutes or seconds
1698 	      -1: Unknown
1699 	   8) min = minutes; sec = seconds */
1700 
1701 	seq_printf(m, "%s %d.%d 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
1702 		   driver_version,
1703 		   (apm_info.bios.version >> 8) & 0xff,
1704 		   apm_info.bios.version & 0xff,
1705 		   apm_info.bios.flags,
1706 		   ac_line_status,
1707 		   battery_status,
1708 		   battery_flag,
1709 		   percentage,
1710 		   time_units,
1711 		   units);
1712 	return 0;
1713 }
1714 #endif
1715 
1716 static int apm(void *unused)
1717 {
1718 	unsigned short	bx;
1719 	unsigned short	cx;
1720 	unsigned short	dx;
1721 	int		error;
1722 	char 		*power_stat;
1723 	char 		*bat_stat;
1724 
1725 	/* 2002/08/01 - WT
1726 	 * This is to avoid random crashes at boot time during initialization
1727 	 * on SMP systems in case of "apm=power-off" mode. Seen on ASUS A7M266D.
1728 	 * Some bioses don't like being called from CPU != 0.
1729 	 * Method suggested by Ingo Molnar.
1730 	 */
1731 	set_cpus_allowed_ptr(current, cpumask_of(0));
1732 	BUG_ON(smp_processor_id() != 0);
1733 
1734 	if (apm_info.connection_version == 0) {
1735 		apm_info.connection_version = apm_info.bios.version;
1736 		if (apm_info.connection_version > 0x100) {
1737 			/*
1738 			 * We only support BIOSs up to version 1.2
1739 			 */
1740 			if (apm_info.connection_version > 0x0102)
1741 				apm_info.connection_version = 0x0102;
1742 			error = apm_driver_version(&apm_info.connection_version);
1743 			if (error != APM_SUCCESS) {
1744 				apm_error("driver version", error);
1745 				/* Fall back to an APM 1.0 connection. */
1746 				apm_info.connection_version = 0x100;
1747 			}
1748 		}
1749 	}
1750 
1751 	if (debug)
1752 		printk(KERN_INFO "apm: Connection version %d.%d\n",
1753 			(apm_info.connection_version >> 8) & 0xff,
1754 			apm_info.connection_version & 0xff);
1755 
1756 #ifdef CONFIG_APM_DO_ENABLE
1757 	if (apm_info.bios.flags & APM_BIOS_DISABLED) {
1758 		/*
1759 		 * This call causes my NEC UltraLite Versa 33/C to hang if it
1760 		 * is booted with PM disabled but not in the docking station.
1761 		 * Unfortunate ...
1762 		 */
1763 		error = apm_enable_power_management(1);
1764 		if (error) {
1765 			apm_error("enable power management", error);
1766 			return -1;
1767 		}
1768 	}
1769 #endif
1770 
1771 	if ((apm_info.bios.flags & APM_BIOS_DISENGAGED)
1772 	    && (apm_info.connection_version > 0x0100)) {
1773 		error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1774 		if (error) {
1775 			apm_error("engage power management", error);
1776 			return -1;
1777 		}
1778 	}
1779 
1780 	if (debug && (num_online_cpus() == 1 || smp)) {
1781 		error = apm_get_power_status(&bx, &cx, &dx);
1782 		if (error)
1783 			printk(KERN_INFO "apm: power status not available\n");
1784 		else {
1785 			switch ((bx >> 8) & 0xff) {
1786 			case 0:
1787 				power_stat = "off line";
1788 				break;
1789 			case 1:
1790 				power_stat = "on line";
1791 				break;
1792 			case 2:
1793 				power_stat = "on backup power";
1794 				break;
1795 			default:
1796 				power_stat = "unknown";
1797 				break;
1798 			}
1799 			switch (bx & 0xff) {
1800 			case 0:
1801 				bat_stat = "high";
1802 				break;
1803 			case 1:
1804 				bat_stat = "low";
1805 				break;
1806 			case 2:
1807 				bat_stat = "critical";
1808 				break;
1809 			case 3:
1810 				bat_stat = "charging";
1811 				break;
1812 			default:
1813 				bat_stat = "unknown";
1814 				break;
1815 			}
1816 			printk(KERN_INFO
1817 			       "apm: AC %s, battery status %s, battery life ",
1818 			       power_stat, bat_stat);
1819 			if ((cx & 0xff) == 0xff)
1820 				printk("unknown\n");
1821 			else
1822 				printk("%d%%\n", cx & 0xff);
1823 			if (apm_info.connection_version > 0x100) {
1824 				printk(KERN_INFO
1825 				       "apm: battery flag 0x%02x, battery life ",
1826 				       (cx >> 8) & 0xff);
1827 				if (dx == 0xffff)
1828 					printk("unknown\n");
1829 				else
1830 					printk("%d %s\n", dx & 0x7fff,
1831 					       (dx & 0x8000) ?
1832 					       "minutes" : "seconds");
1833 			}
1834 		}
1835 	}
1836 
1837 	/* Install our power off handler.. */
1838 	if (power_off)
1839 		pm_power_off = apm_power_off;
1840 
1841 	if (num_online_cpus() == 1 || smp) {
1842 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1843 		console_blank_hook = apm_console_blank;
1844 #endif
1845 		apm_mainloop();
1846 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1847 		console_blank_hook = NULL;
1848 #endif
1849 	}
1850 
1851 	return 0;
1852 }
1853 
1854 #ifndef MODULE
1855 static int __init apm_setup(char *str)
1856 {
1857 	int invert;
1858 
1859 	while ((str != NULL) && (*str != '\0')) {
1860 		if (strncmp(str, "off", 3) == 0)
1861 			apm_disabled = 1;
1862 		if (strncmp(str, "on", 2) == 0)
1863 			apm_disabled = 0;
1864 		if ((strncmp(str, "bounce-interval=", 16) == 0) ||
1865 		    (strncmp(str, "bounce_interval=", 16) == 0))
1866 			bounce_interval = simple_strtol(str + 16, NULL, 0);
1867 		if ((strncmp(str, "idle-threshold=", 15) == 0) ||
1868 		    (strncmp(str, "idle_threshold=", 15) == 0))
1869 			idle_threshold = simple_strtol(str + 15, NULL, 0);
1870 		if ((strncmp(str, "idle-period=", 12) == 0) ||
1871 		    (strncmp(str, "idle_period=", 12) == 0))
1872 			idle_period = simple_strtol(str + 12, NULL, 0);
1873 		invert = (strncmp(str, "no-", 3) == 0) ||
1874 			(strncmp(str, "no_", 3) == 0);
1875 		if (invert)
1876 			str += 3;
1877 		if (strncmp(str, "debug", 5) == 0)
1878 			debug = !invert;
1879 		if ((strncmp(str, "power-off", 9) == 0) ||
1880 		    (strncmp(str, "power_off", 9) == 0))
1881 			power_off = !invert;
1882 		if (strncmp(str, "smp", 3) == 0) {
1883 			smp = !invert;
1884 			idle_threshold = 100;
1885 		}
1886 		if ((strncmp(str, "allow-ints", 10) == 0) ||
1887 		    (strncmp(str, "allow_ints", 10) == 0))
1888 			apm_info.allow_ints = !invert;
1889 		if ((strncmp(str, "broken-psr", 10) == 0) ||
1890 		    (strncmp(str, "broken_psr", 10) == 0))
1891 			apm_info.get_power_status_broken = !invert;
1892 		if ((strncmp(str, "realmode-power-off", 18) == 0) ||
1893 		    (strncmp(str, "realmode_power_off", 18) == 0))
1894 			apm_info.realmode_power_off = !invert;
1895 		str = strchr(str, ',');
1896 		if (str != NULL)
1897 			str += strspn(str, ", \t");
1898 	}
1899 	return 1;
1900 }
1901 
1902 __setup("apm=", apm_setup);
1903 #endif
1904 
1905 static const struct file_operations apm_bios_fops = {
1906 	.owner		= THIS_MODULE,
1907 	.read		= do_read,
1908 	.poll		= do_poll,
1909 	.unlocked_ioctl	= do_ioctl,
1910 	.open		= do_open,
1911 	.release	= do_release,
1912 	.llseek		= noop_llseek,
1913 };
1914 
1915 static struct miscdevice apm_device = {
1916 	APM_MINOR_DEV,
1917 	"apm_bios",
1918 	&apm_bios_fops
1919 };
1920 
1921 
1922 /* Simple "print if true" callback */
1923 static int __init print_if_true(const struct dmi_system_id *d)
1924 {
1925 	printk("%s\n", d->ident);
1926 	return 0;
1927 }
1928 
1929 /*
1930  * Some Bioses enable the PS/2 mouse (touchpad) at resume, even if it was
1931  * disabled before the suspend. Linux used to get terribly confused by that.
1932  */
1933 static int __init broken_ps2_resume(const struct dmi_system_id *d)
1934 {
1935 	printk(KERN_INFO "%s machine detected. Mousepad Resume Bug "
1936 	       "workaround hopefully not needed.\n", d->ident);
1937 	return 0;
1938 }
1939 
1940 /* Some bioses have a broken protected mode poweroff and need to use realmode */
1941 static int __init set_realmode_power_off(const struct dmi_system_id *d)
1942 {
1943 	if (apm_info.realmode_power_off == 0) {
1944 		apm_info.realmode_power_off = 1;
1945 		printk(KERN_INFO "%s bios detected. "
1946 		       "Using realmode poweroff only.\n", d->ident);
1947 	}
1948 	return 0;
1949 }
1950 
1951 /* Some laptops require interrupts to be enabled during APM calls */
1952 static int __init set_apm_ints(const struct dmi_system_id *d)
1953 {
1954 	if (apm_info.allow_ints == 0) {
1955 		apm_info.allow_ints = 1;
1956 		printk(KERN_INFO "%s machine detected. "
1957 		       "Enabling interrupts during APM calls.\n", d->ident);
1958 	}
1959 	return 0;
1960 }
1961 
1962 /* Some APM bioses corrupt memory or just plain do not work */
1963 static int __init apm_is_horked(const struct dmi_system_id *d)
1964 {
1965 	if (apm_info.disabled == 0) {
1966 		apm_info.disabled = 1;
1967 		printk(KERN_INFO "%s machine detected. "
1968 		       "Disabling APM.\n", d->ident);
1969 	}
1970 	return 0;
1971 }
1972 
1973 static int __init apm_is_horked_d850md(const struct dmi_system_id *d)
1974 {
1975 	if (apm_info.disabled == 0) {
1976 		apm_info.disabled = 1;
1977 		printk(KERN_INFO "%s machine detected. "
1978 		       "Disabling APM.\n", d->ident);
1979 		printk(KERN_INFO "This bug is fixed in bios P15 which is available for\n");
1980 		printk(KERN_INFO "download from support.intel.com\n");
1981 	}
1982 	return 0;
1983 }
1984 
1985 /* Some APM bioses hang on APM idle calls */
1986 static int __init apm_likes_to_melt(const struct dmi_system_id *d)
1987 {
1988 	if (apm_info.forbid_idle == 0) {
1989 		apm_info.forbid_idle = 1;
1990 		printk(KERN_INFO "%s machine detected. "
1991 		       "Disabling APM idle calls.\n", d->ident);
1992 	}
1993 	return 0;
1994 }
1995 
1996 /*
1997  *  Check for clue free BIOS implementations who use
1998  *  the following QA technique
1999  *
2000  *      [ Write BIOS Code ]<------
2001  *               |                ^
2002  *      < Does it Compile >----N--
2003  *               |Y               ^
2004  *	< Does it Boot Win98 >-N--
2005  *               |Y
2006  *           [Ship It]
2007  *
2008  *	Phoenix A04  08/24/2000 is known bad (Dell Inspiron 5000e)
2009  *	Phoenix A07  09/29/2000 is known good (Dell Inspiron 5000)
2010  */
2011 static int __init broken_apm_power(const struct dmi_system_id *d)
2012 {
2013 	apm_info.get_power_status_broken = 1;
2014 	printk(KERN_WARNING "BIOS strings suggest APM bugs, "
2015 	       "disabling power status reporting.\n");
2016 	return 0;
2017 }
2018 
2019 /*
2020  * This bios swaps the APM minute reporting bytes over (Many sony laptops
2021  * have this problem).
2022  */
2023 static int __init swab_apm_power_in_minutes(const struct dmi_system_id *d)
2024 {
2025 	apm_info.get_power_status_swabinminutes = 1;
2026 	printk(KERN_WARNING "BIOS strings suggest APM reports battery life "
2027 	       "in minutes and wrong byte order.\n");
2028 	return 0;
2029 }
2030 
2031 static const struct dmi_system_id apm_dmi_table[] __initconst = {
2032 	{
2033 		print_if_true,
2034 		KERN_WARNING "IBM T23 - BIOS 1.03b+ and controller firmware 1.02+ may be needed for Linux APM.",
2035 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
2036 			DMI_MATCH(DMI_BIOS_VERSION, "1AET38WW (1.01b)"), },
2037 	},
2038 	{	/* Handle problems with APM on the C600 */
2039 		broken_ps2_resume, "Dell Latitude C600",
2040 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
2041 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C600"), },
2042 	},
2043 	{	/* Allow interrupts during suspend on Dell Latitude laptops*/
2044 		set_apm_ints, "Dell Latitude",
2045 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2046 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C510"), }
2047 	},
2048 	{	/* APM crashes */
2049 		apm_is_horked, "Dell Inspiron 2500",
2050 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2051 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2052 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2053 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2054 	},
2055 	{	/* Allow interrupts during suspend on Dell Inspiron laptops*/
2056 		set_apm_ints, "Dell Inspiron", {
2057 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2058 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 4000"), },
2059 	},
2060 	{	/* Handle problems with APM on Inspiron 5000e */
2061 		broken_apm_power, "Dell Inspiron 5000e",
2062 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2063 			DMI_MATCH(DMI_BIOS_VERSION, "A04"),
2064 			DMI_MATCH(DMI_BIOS_DATE, "08/24/2000"), },
2065 	},
2066 	{	/* Handle problems with APM on Inspiron 2500 */
2067 		broken_apm_power, "Dell Inspiron 2500",
2068 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2069 			DMI_MATCH(DMI_BIOS_VERSION, "A12"),
2070 			DMI_MATCH(DMI_BIOS_DATE, "02/04/2002"), },
2071 	},
2072 	{	/* APM crashes */
2073 		apm_is_horked, "Dell Dimension 4100",
2074 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2075 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"),
2076 			DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2077 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2078 	},
2079 	{	/* Allow interrupts during suspend on Compaq Laptops*/
2080 		set_apm_ints, "Compaq 12XL125",
2081 		{	DMI_MATCH(DMI_SYS_VENDOR, "Compaq"),
2082 			DMI_MATCH(DMI_PRODUCT_NAME, "Compaq PC"),
2083 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2084 			DMI_MATCH(DMI_BIOS_VERSION, "4.06"), },
2085 	},
2086 	{	/* Allow interrupts during APM or the clock goes slow */
2087 		set_apm_ints, "ASUSTeK",
2088 		{	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
2089 			DMI_MATCH(DMI_PRODUCT_NAME, "L8400K series Notebook PC"), },
2090 	},
2091 	{	/* APM blows on shutdown */
2092 		apm_is_horked, "ABIT KX7-333[R]",
2093 		{	DMI_MATCH(DMI_BOARD_VENDOR, "ABIT"),
2094 			DMI_MATCH(DMI_BOARD_NAME, "VT8367-8233A (KX7-333[R])"), },
2095 	},
2096 	{	/* APM crashes */
2097 		apm_is_horked, "Trigem Delhi3",
2098 		{	DMI_MATCH(DMI_SYS_VENDOR, "TriGem Computer, Inc"),
2099 			DMI_MATCH(DMI_PRODUCT_NAME, "Delhi3"), },
2100 	},
2101 	{	/* APM crashes */
2102 		apm_is_horked, "Fujitsu-Siemens",
2103 		{	DMI_MATCH(DMI_BIOS_VENDOR, "hoenix/FUJITSU SIEMENS"),
2104 			DMI_MATCH(DMI_BIOS_VERSION, "Version1.01"), },
2105 	},
2106 	{	/* APM crashes */
2107 		apm_is_horked_d850md, "Intel D850MD",
2108 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2109 			DMI_MATCH(DMI_BIOS_VERSION, "MV85010A.86A.0016.P07.0201251536"), },
2110 	},
2111 	{	/* APM crashes */
2112 		apm_is_horked, "Intel D810EMO",
2113 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2114 			DMI_MATCH(DMI_BIOS_VERSION, "MO81010A.86A.0008.P04.0004170800"), },
2115 	},
2116 	{	/* APM crashes */
2117 		apm_is_horked, "Dell XPS-Z",
2118 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2119 			DMI_MATCH(DMI_BIOS_VERSION, "A11"),
2120 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"), },
2121 	},
2122 	{	/* APM crashes */
2123 		apm_is_horked, "Sharp PC-PJ/AX",
2124 		{	DMI_MATCH(DMI_SYS_VENDOR, "SHARP"),
2125 			DMI_MATCH(DMI_PRODUCT_NAME, "PC-PJ/AX"),
2126 			DMI_MATCH(DMI_BIOS_VENDOR, "SystemSoft"),
2127 			DMI_MATCH(DMI_BIOS_VERSION, "Version R2.08"), },
2128 	},
2129 	{	/* APM crashes */
2130 		apm_is_horked, "Dell Inspiron 2500",
2131 		{	DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2132 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2133 			DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2134 			DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2135 	},
2136 	{	/* APM idle hangs */
2137 		apm_likes_to_melt, "Jabil AMD",
2138 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2139 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP06"), },
2140 	},
2141 	{	/* APM idle hangs */
2142 		apm_likes_to_melt, "AMI Bios",
2143 		{	DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2144 			DMI_MATCH(DMI_BIOS_VERSION, "0AASNP05"), },
2145 	},
2146 	{	/* Handle problems with APM on Sony Vaio PCG-N505X(DE) */
2147 		swab_apm_power_in_minutes, "Sony VAIO",
2148 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2149 			DMI_MATCH(DMI_BIOS_VERSION, "R0206H"),
2150 			DMI_MATCH(DMI_BIOS_DATE, "08/23/99"), },
2151 	},
2152 	{	/* Handle problems with APM on Sony Vaio PCG-N505VX */
2153 		swab_apm_power_in_minutes, "Sony VAIO",
2154 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2155 			DMI_MATCH(DMI_BIOS_VERSION, "W2K06H0"),
2156 			DMI_MATCH(DMI_BIOS_DATE, "02/03/00"), },
2157 	},
2158 	{	/* Handle problems with APM on Sony Vaio PCG-XG29 */
2159 		swab_apm_power_in_minutes, "Sony VAIO",
2160 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2161 			DMI_MATCH(DMI_BIOS_VERSION, "R0117A0"),
2162 			DMI_MATCH(DMI_BIOS_DATE, "04/25/00"), },
2163 	},
2164 	{	/* Handle problems with APM on Sony Vaio PCG-Z600NE */
2165 		swab_apm_power_in_minutes, "Sony VAIO",
2166 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2167 			DMI_MATCH(DMI_BIOS_VERSION, "R0121Z1"),
2168 			DMI_MATCH(DMI_BIOS_DATE, "05/11/00"), },
2169 	},
2170 	{	/* Handle problems with APM on Sony Vaio PCG-Z600NE */
2171 		swab_apm_power_in_minutes, "Sony VAIO",
2172 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2173 			DMI_MATCH(DMI_BIOS_VERSION, "WME01Z1"),
2174 			DMI_MATCH(DMI_BIOS_DATE, "08/11/00"), },
2175 	},
2176 	{	/* Handle problems with APM on Sony Vaio PCG-Z600LEK(DE) */
2177 		swab_apm_power_in_minutes, "Sony VAIO",
2178 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2179 			DMI_MATCH(DMI_BIOS_VERSION, "R0206Z3"),
2180 			DMI_MATCH(DMI_BIOS_DATE, "12/25/00"), },
2181 	},
2182 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS */
2183 		swab_apm_power_in_minutes, "Sony VAIO",
2184 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2185 			DMI_MATCH(DMI_BIOS_VERSION, "R0203D0"),
2186 			DMI_MATCH(DMI_BIOS_DATE, "05/12/00"), },
2187 	},
2188 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS */
2189 		swab_apm_power_in_minutes, "Sony VAIO",
2190 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2191 			DMI_MATCH(DMI_BIOS_VERSION, "R0203Z3"),
2192 			DMI_MATCH(DMI_BIOS_DATE, "08/25/00"), },
2193 	},
2194 	{	/* Handle problems with APM on Sony Vaio PCG-Z505LS (with updated BIOS) */
2195 		swab_apm_power_in_minutes, "Sony VAIO",
2196 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2197 			DMI_MATCH(DMI_BIOS_VERSION, "R0209Z3"),
2198 			DMI_MATCH(DMI_BIOS_DATE, "05/12/01"), },
2199 	},
2200 	{	/* Handle problems with APM on Sony Vaio PCG-F104K */
2201 		swab_apm_power_in_minutes, "Sony VAIO",
2202 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2203 			DMI_MATCH(DMI_BIOS_VERSION, "R0204K2"),
2204 			DMI_MATCH(DMI_BIOS_DATE, "08/28/00"), },
2205 	},
2206 
2207 	{	/* Handle problems with APM on Sony Vaio PCG-C1VN/C1VE */
2208 		swab_apm_power_in_minutes, "Sony VAIO",
2209 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2210 			DMI_MATCH(DMI_BIOS_VERSION, "R0208P1"),
2211 			DMI_MATCH(DMI_BIOS_DATE, "11/09/00"), },
2212 	},
2213 	{	/* Handle problems with APM on Sony Vaio PCG-C1VE */
2214 		swab_apm_power_in_minutes, "Sony VAIO",
2215 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2216 			DMI_MATCH(DMI_BIOS_VERSION, "R0204P1"),
2217 			DMI_MATCH(DMI_BIOS_DATE, "09/12/00"), },
2218 	},
2219 	{	/* Handle problems with APM on Sony Vaio PCG-C1VE */
2220 		swab_apm_power_in_minutes, "Sony VAIO",
2221 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2222 			DMI_MATCH(DMI_BIOS_VERSION, "WXPO1Z3"),
2223 			DMI_MATCH(DMI_BIOS_DATE, "10/26/01"), },
2224 	},
2225 	{	/* broken PM poweroff bios */
2226 		set_realmode_power_off, "Award Software v4.60 PGMA",
2227 		{	DMI_MATCH(DMI_BIOS_VENDOR, "Award Software International, Inc."),
2228 			DMI_MATCH(DMI_BIOS_VERSION, "4.60 PGMA"),
2229 			DMI_MATCH(DMI_BIOS_DATE, "134526184"), },
2230 	},
2231 
2232 	/* Generic per vendor APM settings  */
2233 
2234 	{	/* Allow interrupts during suspend on IBM laptops */
2235 		set_apm_ints, "IBM",
2236 		{	DMI_MATCH(DMI_SYS_VENDOR, "IBM"), },
2237 	},
2238 
2239 	{ }
2240 };
2241 
2242 /*
2243  * Just start the APM thread. We do NOT want to do APM BIOS
2244  * calls from anything but the APM thread, if for no other reason
2245  * than the fact that we don't trust the APM BIOS. This way,
2246  * most common APM BIOS problems that lead to protection errors
2247  * etc will have at least some level of being contained...
2248  *
2249  * In short, if something bad happens, at least we have a choice
2250  * of just killing the apm thread..
2251  */
2252 static int __init apm_init(void)
2253 {
2254 	struct desc_struct *gdt;
2255 	int err;
2256 
2257 	dmi_check_system(apm_dmi_table);
2258 
2259 	if (apm_info.bios.version == 0 || machine_is_olpc()) {
2260 		printk(KERN_INFO "apm: BIOS not found.\n");
2261 		return -ENODEV;
2262 	}
2263 	printk(KERN_INFO
2264 	       "apm: BIOS version %d.%d Flags 0x%02x (Driver version %s)\n",
2265 	       ((apm_info.bios.version >> 8) & 0xff),
2266 	       (apm_info.bios.version & 0xff),
2267 	       apm_info.bios.flags,
2268 	       driver_version);
2269 	if ((apm_info.bios.flags & APM_32_BIT_SUPPORT) == 0) {
2270 		printk(KERN_INFO "apm: no 32 bit BIOS support\n");
2271 		return -ENODEV;
2272 	}
2273 
2274 	if (allow_ints)
2275 		apm_info.allow_ints = 1;
2276 	if (broken_psr)
2277 		apm_info.get_power_status_broken = 1;
2278 	if (realmode_power_off)
2279 		apm_info.realmode_power_off = 1;
2280 	/* User can override, but default is to trust DMI */
2281 	if (apm_disabled != -1)
2282 		apm_info.disabled = apm_disabled;
2283 
2284 	/*
2285 	 * Fix for the Compaq Contura 3/25c which reports BIOS version 0.1
2286 	 * but is reportedly a 1.0 BIOS.
2287 	 */
2288 	if (apm_info.bios.version == 0x001)
2289 		apm_info.bios.version = 0x100;
2290 
2291 	/* BIOS < 1.2 doesn't set cseg_16_len */
2292 	if (apm_info.bios.version < 0x102)
2293 		apm_info.bios.cseg_16_len = 0; /* 64k */
2294 
2295 	if (debug) {
2296 		printk(KERN_INFO "apm: entry %x:%x cseg16 %x dseg %x",
2297 			apm_info.bios.cseg, apm_info.bios.offset,
2298 			apm_info.bios.cseg_16, apm_info.bios.dseg);
2299 		if (apm_info.bios.version > 0x100)
2300 			printk(" cseg len %x, dseg len %x",
2301 				apm_info.bios.cseg_len,
2302 				apm_info.bios.dseg_len);
2303 		if (apm_info.bios.version > 0x101)
2304 			printk(" cseg16 len %x", apm_info.bios.cseg_16_len);
2305 		printk("\n");
2306 	}
2307 
2308 	if (apm_info.disabled) {
2309 		pr_notice("disabled on user request.\n");
2310 		return -ENODEV;
2311 	}
2312 	if ((num_online_cpus() > 1) && !power_off && !smp) {
2313 		pr_notice("disabled - APM is not SMP safe.\n");
2314 		apm_info.disabled = 1;
2315 		return -ENODEV;
2316 	}
2317 	if (!acpi_disabled) {
2318 		pr_notice("overridden by ACPI.\n");
2319 		apm_info.disabled = 1;
2320 		return -ENODEV;
2321 	}
2322 
2323 	/*
2324 	 * Set up the long jump entry point to the APM BIOS, which is called
2325 	 * from inline assembly.
2326 	 */
2327 	apm_bios_entry.offset = apm_info.bios.offset;
2328 	apm_bios_entry.segment = APM_CS;
2329 
2330 	/*
2331 	 * The APM 1.1 BIOS is supposed to provide limit information that it
2332 	 * recognizes.  Many machines do this correctly, but many others do
2333 	 * not restrict themselves to their claimed limit.  When this happens,
2334 	 * they will cause a segmentation violation in the kernel at boot time.
2335 	 * Most BIOS's, however, will respect a 64k limit, so we use that.
2336 	 *
2337 	 * Note we only set APM segments on CPU zero, since we pin the APM
2338 	 * code to that CPU.
2339 	 */
2340 	gdt = get_cpu_gdt_rw(0);
2341 	set_desc_base(&gdt[APM_CS >> 3],
2342 		 (unsigned long)__va((unsigned long)apm_info.bios.cseg << 4));
2343 	set_desc_base(&gdt[APM_CS_16 >> 3],
2344 		 (unsigned long)__va((unsigned long)apm_info.bios.cseg_16 << 4));
2345 	set_desc_base(&gdt[APM_DS >> 3],
2346 		 (unsigned long)__va((unsigned long)apm_info.bios.dseg << 4));
2347 
2348 	proc_create_single("apm", 0, NULL, proc_apm_show);
2349 
2350 	kapmd_task = kthread_create(apm, NULL, "kapmd");
2351 	if (IS_ERR(kapmd_task)) {
2352 		pr_err("disabled - Unable to start kernel thread\n");
2353 		err = PTR_ERR(kapmd_task);
2354 		kapmd_task = NULL;
2355 		remove_proc_entry("apm", NULL);
2356 		return err;
2357 	}
2358 	wake_up_process(kapmd_task);
2359 
2360 	if (num_online_cpus() > 1 && !smp) {
2361 		printk(KERN_NOTICE
2362 		       "apm: disabled - APM is not SMP safe (power off active).\n");
2363 		return 0;
2364 	}
2365 
2366 	/*
2367 	 * Note we don't actually care if the misc_device cannot be registered.
2368 	 * this driver can do its job without it, even if userspace can't
2369 	 * control it.  just log the error
2370 	 */
2371 	if (misc_register(&apm_device))
2372 		printk(KERN_WARNING "apm: Could not register misc device.\n");
2373 
2374 	if (HZ != 100)
2375 		idle_period = (idle_period * HZ) / 100;
2376 	if (idle_threshold < 100) {
2377 		cpuidle_poll_state_init(&apm_idle_driver);
2378 		if (!cpuidle_register_driver(&apm_idle_driver))
2379 			if (cpuidle_register_device(&apm_cpuidle_device))
2380 				cpuidle_unregister_driver(&apm_idle_driver);
2381 	}
2382 
2383 	return 0;
2384 }
2385 
2386 static void __exit apm_exit(void)
2387 {
2388 	int error;
2389 
2390 	cpuidle_unregister_device(&apm_cpuidle_device);
2391 	cpuidle_unregister_driver(&apm_idle_driver);
2392 
2393 	if (((apm_info.bios.flags & APM_BIOS_DISENGAGED) == 0)
2394 	    && (apm_info.connection_version > 0x0100)) {
2395 		error = apm_engage_power_management(APM_DEVICE_ALL, 0);
2396 		if (error)
2397 			apm_error("disengage power management", error);
2398 	}
2399 	misc_deregister(&apm_device);
2400 	remove_proc_entry("apm", NULL);
2401 	if (power_off)
2402 		pm_power_off = NULL;
2403 	if (kapmd_task) {
2404 		kthread_stop(kapmd_task);
2405 		kapmd_task = NULL;
2406 	}
2407 }
2408 
2409 module_init(apm_init);
2410 module_exit(apm_exit);
2411 
2412 MODULE_AUTHOR("Stephen Rothwell");
2413 MODULE_DESCRIPTION("Advanced Power Management");
2414 MODULE_LICENSE("GPL");
2415 module_param(debug, bool, 0644);
2416 MODULE_PARM_DESC(debug, "Enable debug mode");
2417 module_param(power_off, bool, 0444);
2418 MODULE_PARM_DESC(power_off, "Enable power off");
2419 module_param(bounce_interval, int, 0444);
2420 MODULE_PARM_DESC(bounce_interval,
2421 		"Set the number of ticks to ignore suspend bounces");
2422 module_param(allow_ints, bool, 0444);
2423 MODULE_PARM_DESC(allow_ints, "Allow interrupts during BIOS calls");
2424 module_param(broken_psr, bool, 0444);
2425 MODULE_PARM_DESC(broken_psr, "BIOS has a broken GetPowerStatus call");
2426 module_param(realmode_power_off, bool, 0444);
2427 MODULE_PARM_DESC(realmode_power_off,
2428 		"Switch to real mode before powering off");
2429 module_param(idle_threshold, int, 0444);
2430 MODULE_PARM_DESC(idle_threshold,
2431 	"System idle percentage above which to make APM BIOS idle calls");
2432 module_param(idle_period, int, 0444);
2433 MODULE_PARM_DESC(idle_period,
2434 	"Period (in sec/100) over which to calculate the idle percentage");
2435 module_param(smp, bool, 0444);
2436 MODULE_PARM_DESC(smp,
2437 	"Set this to enable APM use on an SMP platform. Use with caution on older systems");
2438 MODULE_ALIAS_MISCDEV(APM_MINOR_DEV);
2439