2 * APM BIOS driver for Linux
3 * Copyright 1994-2001 Stephen Rothwell (sfr@canb.auug.org.au)
5 * Initial development of this driver was funded by NEC Australia P/L
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the
10 * Free Software Foundation; either version 2, or (at your option) any
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
18 * October 1995, Rik Faith (faith@cs.unc.edu):
19 * Minor enhancements and updates (to the patch set) for 1.3.x
21 * January 1996, Rik Faith (faith@cs.unc.edu):
22 * Make /proc/apm easy to format (bump driver version)
23 * March 1996, Rik Faith (faith@cs.unc.edu):
24 * Prohibit APM BIOS calls unless apm_enabled.
25 * (Thanks to Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>)
26 * April 1996, Stephen Rothwell (sfr@canb.auug.org.au)
28 * May 1996, Version 1.2
29 * Feb 1998, Version 1.3
30 * Feb 1998, Version 1.4
31 * Aug 1998, Version 1.5
32 * Sep 1998, Version 1.6
33 * Nov 1998, Version 1.7
34 * Jan 1999, Version 1.8
35 * Jan 1999, Version 1.9
36 * Oct 1999, Version 1.10
37 * Nov 1999, Version 1.11
38 * Jan 2000, Version 1.12
39 * Feb 2000, Version 1.13
40 * Nov 2000, Version 1.14
41 * Oct 2001, Version 1.15
42 * Jan 2002, Version 1.16
43 * Oct 2002, Version 1.16ac
46 * 0.6b: first version in official kernel, Linux 1.3.46
47 * 0.7: changed /proc/apm format, Linux 1.3.58
48 * 0.8: fixed gcc 2.7.[12] compilation problems, Linux 1.3.59
49 * 0.9: only call bios if bios is present, Linux 1.3.72
50 * 1.0: use fixed device number, consolidate /proc/apm into this file,
52 * 1.1: support user-space standby and suspend, power off after system
53 * halted, Linux 1.3.98
54 * 1.2: When resetting RTC after resume, take care so that the time
55 * is only incorrect by 30-60mS (vs. 1S previously) (Gabor J. Toth
56 * <jtoth@princeton.edu>); improve interaction between
57 * screen-blanking and gpm (Stephen Rothwell); Linux 1.99.4
58 * 1.2a:Simple change to stop mysterious bug reports with SMP also added
59 * levels to the printk calls. APM is not defined for SMP machines.
60 * The new replacement for it is, but Linux doesn't yet support this.
61 * Alan Cox Linux 2.1.55
62 * 1.3: Set up a valid data descriptor 0x40 for buggy BIOS's
63 * 1.4: Upgraded to support APM 1.2. Integrated ThinkPad suspend patch by
64 * Dean Gaudet <dgaudet@arctic.org>.
65 * C. Scott Ananian <cananian@alumni.princeton.edu> Linux 2.1.87
66 * 1.5: Fix segment register reloading (in case of bad segments saved
69 * 1.6: Cope with compiler/assembler differences.
70 * Only try to turn off the first display device.
71 * Fix OOPS at power off with no APM BIOS by Jan Echternach
72 * <echter@informatik.uni-rostock.de>
74 * 1.7: Modify driver's cached copy of the disabled/disengaged flags
75 * to reflect current state of APM BIOS.
76 * Chris Rankin <rankinc@bellsouth.net>
77 * Reset interrupt 0 timer to 100Hz after suspend
78 * Chad Miller <cmiller@surfsouth.com>
79 * Add CONFIG_APM_IGNORE_SUSPEND_BOUNCE
80 * Richard Gooch <rgooch@atnf.csiro.au>
81 * Allow boot time disabling of APM
82 * Make boot messages far less verbose by default
85 * 1.8: Add CONFIG_APM_RTC_IS_GMT
86 * Richard Gooch <rgooch@atnf.csiro.au>
87 * change APM_NOINTS to CONFIG_APM_ALLOW_INTS
88 * remove dependency on CONFIG_PROC_FS
90 * 1.9: Fix small typo. <laslo@wodip.opole.pl>
91 * Try to cope with BIOS's that need to have all display
92 * devices blanked and not just the first one.
93 * Ross Paterson <ross@soi.city.ac.uk>
94 * Fix segment limit setting it has always been wrong as
95 * the segments needed to have byte granularity.
96 * Mark a few things __init.
97 * Add hack to allow power off of SMP systems by popular request.
98 * Use CONFIG_SMP instead of __SMP__
99 * Ignore BOUNCES for three seconds.
101 * 1.10: Fix for Thinkpad return code.
102 * Merge 2.2 and 2.3 drivers.
103 * Remove APM dependencies in arch/i386/kernel/process.c
104 * Remove APM dependencies in drivers/char/sysrq.c
105 * Reset time across standby.
106 * Allow more inititialisation on SMP.
107 * Remove CONFIG_APM_POWER_OFF and make it boot time
108 * configurable (default on).
109 * Make debug only a boot time parameter (remove APM_DEBUG).
110 * Try to blank all devices on any error.
111 * 1.11: Remove APM dependencies in drivers/char/console.c
112 * Check nr_running to detect if we are idle (from
113 * Borislav Deianov <borislav@lix.polytechnique.fr>)
114 * Fix for bioses that don't zero the top part of the
115 * entrypoint offset (Mario Sitta <sitta@al.unipmn.it>)
116 * (reported by Panos Katsaloulis <teras@writeme.com>).
117 * Real mode power off patch (Walter Hofmann
118 * <Walter.Hofmann@physik.stud.uni-erlangen.de>).
119 * 1.12: Remove CONFIG_SMP as the compiler will optimize
120 * the code away anyway (smp_num_cpus == 1 in UP)
121 * noted by Artur Skawina <skawina@geocities.com>.
122 * Make power off under SMP work again.
123 * Fix thinko with initial engaging of BIOS.
124 * Make sure power off only happens on CPU 0
125 * (Paul "Rusty" Russell <rusty@rustcorp.com.au>).
126 * Do error notification to user mode if BIOS calls fail.
127 * Move entrypoint offset fix to ...boot/setup.S
128 * where it belongs (Cosmos <gis88564@cis.nctu.edu.tw>).
129 * Remove smp-power-off. SMP users must now specify
130 * "apm=power-off" on the kernel command line. Suggested
131 * by Jim Avera <jima@hal.com>, modified by Alan Cox
132 * <alan@lxorguk.ukuu.org.uk>.
133 * Register the /proc/apm entry even on SMP so that
134 * scripts that check for it before doing power off
135 * work (Jim Avera <jima@hal.com>).
136 * 1.13: Changes for new pm_ interfaces (Andy Henroid
137 * <andy_henroid@yahoo.com>).
138 * Modularize the code.
139 * Fix the Thinkpad (again) :-( (CONFIG_APM_IGNORE_MULTIPLE_SUSPENDS
140 * is now the way life works).
141 * Fix thinko in suspend() (wrong return).
142 * Notify drivers on critical suspend.
143 * Make kapmd absorb more idle time (Pavel Machek <pavel@ucw.cz>
145 * Disable interrupts while we are suspended (Andy Henroid
146 * <andy_henroid@yahoo.com> fixed by sfr).
147 * Make power off work on SMP again (Tony Hoyle
148 * <tmh@magenta-logic.com> and <zlatko@iskon.hr>) modified by sfr.
149 * Remove CONFIG_APM_SUSPEND_BOUNCE. The bounce ignore
150 * interval is now configurable.
151 * 1.14: Make connection version persist across module unload/load.
152 * Enable and engage power management earlier.
153 * Disengage power management on module unload.
154 * Changed to use the sysrq-register hack for registering the
155 * power off function called by magic sysrq based upon discussions
156 * in irc://irc.openprojects.net/#kernelnewbies
157 * (Crutcher Dunnavant <crutcher+kernel@datastacks.com>).
158 * Make CONFIG_APM_REAL_MODE_POWER_OFF run time configurable.
159 * (Arjan van de Ven <arjanv@redhat.com>) modified by sfr.
160 * Work around byte swap bug in one of the Vaio's BIOS's
161 * (Marc Boucher <marc@mbsi.ca>).
162 * Exposed the disable flag to dmi so that we can handle known
163 * broken APM (Alan Cox <alan@lxorguk.ukuu.org.uk>).
164 * 1.14ac: If the BIOS says "I slowed the CPU down" then don't spin
165 * calling it - instead idle. (Alan Cox <alan@lxorguk.ukuu.org.uk>)
166 * If an APM idle fails log it and idle sensibly
167 * 1.15: Don't queue events to clients who open the device O_WRONLY.
168 * Don't expect replies from clients who open the device O_RDONLY.
169 * (Idea from Thomas Hood)
170 * Minor waitqueue cleanups. (John Fremlin <chief@bandits.org>)
171 * 1.16: Fix idle calling. (Andreas Steinmetz <ast@domdv.de> et al.)
172 * Notify listeners of standby or suspend events before notifying
173 * drivers. Return EBUSY to ioctl() if suspend is rejected.
174 * (Russell King <rmk@arm.linux.org.uk> and Thomas Hood)
175 * Ignore first resume after we generate our own resume event
176 * after a suspend (Thomas Hood)
177 * Daemonize now gets rid of our controlling terminal (sfr).
178 * CONFIG_APM_CPU_IDLE now just affects the default value of
179 * idle_threshold (sfr).
180 * Change name of kernel apm daemon (as it no longer idles) (sfr).
181 * 1.16ac: Fix up SMP support somewhat. You can now force SMP on and we
182 * make _all_ APM calls on the CPU#0. Fix unsafe sign bug.
183 * TODO: determine if its "boot CPU" or "CPU0" we want to lock to.
187 * Intel Corporation, Microsoft Corporation. Advanced Power Management
188 * (APM) BIOS Interface Specification, Revision 1.1, September 1993.
189 * Intel Order Number 241704-001. Microsoft Part Number 781-110-X01.
191 * [This document is available free from Intel by calling 800.628.8686 (fax
192 * 916.356.6100) or 800.548.4725; or from
193 * http://www.microsoft.com/whdc/archive/amp_12.mspx It is also
194 * available from Microsoft by calling 206.882.8080.]
197 * Intel Corporation, Microsoft Corporation. Advanced Power Management
198 * (APM) BIOS Interface Specification, Revision 1.2, February 1996.
200 * [This document is available from Microsoft at:
201 * http://www.microsoft.com/whdc/archive/amp_12.mspx]
204 #define pr_fmt(fmt) "apm: " fmt
206 #include <linux/module.h>
208 #include <linux/poll.h>
209 #include <linux/types.h>
210 #include <linux/stddef.h>
211 #include <linux/timer.h>
212 #include <linux/fcntl.h>
213 #include <linux/slab.h>
214 #include <linux/stat.h>
215 #include <linux/proc_fs.h>
216 #include <linux/seq_file.h>
217 #include <linux/miscdevice.h>
218 #include <linux/apm_bios.h>
219 #include <linux/init.h>
220 #include <linux/time.h>
221 #include <linux/sched.h>
222 #include <linux/pm.h>
223 #include <linux/capability.h>
224 #include <linux/device.h>
225 #include <linux/kernel.h>
226 #include <linux/freezer.h>
227 #include <linux/smp.h>
228 #include <linux/dmi.h>
229 #include <linux/suspend.h>
230 #include <linux/kthread.h>
231 #include <linux/jiffies.h>
232 #include <linux/acpi.h>
233 #include <linux/syscore_ops.h>
234 #include <linux/i8253.h>
235 #include <linux/cpuidle.h>
237 #include <asm/uaccess.h>
238 #include <asm/desc.h>
239 #include <asm/olpc.h>
240 #include <asm/paravirt.h>
241 #include <asm/reboot.h>
242 #include <asm/nospec-branch.h>
244 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
245 extern int (*console_blank_hook)(int);
249 * The apm_bios device is one of the misc char devices.
250 * This is its minor number.
252 #define APM_MINOR_DEV 134
255 * Various options can be changed at boot time as follows:
256 * (We allow underscores for compatibility with the modules code)
257 * apm=on/off enable/disable APM
258 * [no-]allow[-_]ints allow interrupts during BIOS calls
259 * [no-]broken[-_]psr BIOS has a broken GetPowerStatus call
260 * [no-]realmode[-_]power[-_]off switch to real mode before
262 * [no-]debug log some debugging messages
263 * [no-]power[-_]off power off on shutdown
264 * [no-]smp Use apm even on an SMP box
265 * bounce[-_]interval=<n> number of ticks to ignore suspend
267 * idle[-_]threshold=<n> System idle percentage above which to
268 * make APM BIOS idle calls. Set it to
270 * idle[-_]period=<n> Period (in 1/100s of a second) over
271 * which the idle percentage is
275 /* KNOWN PROBLEM MACHINES:
277 * U: TI 4000M TravelMate: BIOS is *NOT* APM compliant
278 * [Confirmed by TI representative]
279 * ?: ACER 486DX4/75: uses dseg 0040, in violation of APM specification
280 * [Confirmed by BIOS disassembly]
281 * [This may work now ...]
282 * P: Toshiba 1950S: battery life information only gets updated after resume
283 * P: Midwest Micro Soundbook Elite DX2/66 monochrome: screen blanking
284 * broken in BIOS [Reported by Garst R. Reese <reese@isn.net>]
285 * ?: AcerNote-950: oops on reading /proc/apm - workaround is a WIP
286 * Neale Banks <neale@lowendale.com.au> December 2000
288 * Legend: U = unusable with APM patches
289 * P = partially usable with APM patches
293 * Define as 1 to make the driver always call the APM BIOS busy
294 * routine even if the clock was not reported as slowed by the
295 * idle routine. Otherwise, define as 0.
297 #define ALWAYS_CALL_BUSY 1
300 * Define to make the APM BIOS calls zero all data segment registers (so
301 * that an incorrect BIOS implementation will cause a kernel panic if it
302 * tries to write to arbitrary memory).
304 #define APM_ZERO_SEGS
309 * Define to re-initialize the interrupt 0 timer to 100 Hz after a suspend.
310 * This patched by Chad Miller <cmiller@surfsouth.com>, original code by
311 * David Chen <chen@ctpa04.mit.edu>
313 #undef INIT_TIMER_AFTER_SUSPEND
315 #ifdef INIT_TIMER_AFTER_SUSPEND
316 #include <linux/timex.h>
318 #include <linux/delay.h>
322 * Need to poll the APM BIOS every second
324 #define APM_CHECK_TIMEOUT (HZ)
327 * Ignore suspend events for this amount of time after a resume
329 #define DEFAULT_BOUNCE_INTERVAL (3 * HZ)
332 * Maximum number of events stored
334 #define APM_MAX_EVENTS 20
337 * The per-file APM data
341 struct apm_user *next;
342 unsigned int suser: 1;
343 unsigned int writer: 1;
344 unsigned int reader: 1;
345 unsigned int suspend_wait: 1;
347 int suspends_pending;
348 int standbys_pending;
353 apm_event_t events[APM_MAX_EVENTS];
357 * The magic number in apm_user
359 #define APM_BIOS_MAGIC 0x4101
362 * idle percentage above which bios idle calls are done
364 #ifdef CONFIG_APM_CPU_IDLE
365 #define DEFAULT_IDLE_THRESHOLD 95
367 #define DEFAULT_IDLE_THRESHOLD 100
369 #define DEFAULT_IDLE_PERIOD (100 / 3)
371 static int apm_cpu_idle(struct cpuidle_device *dev,
372 struct cpuidle_driver *drv, int index);
374 static struct cpuidle_driver apm_idle_driver = {
376 .owner = THIS_MODULE,
378 { /* entry 0 is for polling */ },
379 { /* entry 1 is for APM idle */
382 .exit_latency = 250, /* WAG */
383 .target_residency = 500, /* WAG */
384 .enter = &apm_cpu_idle
390 static struct cpuidle_device apm_cpuidle_device;
396 unsigned long offset;
397 unsigned short segment;
399 static int clock_slowed;
400 static int idle_threshold __read_mostly = DEFAULT_IDLE_THRESHOLD;
401 static int idle_period __read_mostly = DEFAULT_IDLE_PERIOD;
402 static int suspends_pending;
403 static int standbys_pending;
404 static int ignore_sys_suspend;
405 static int ignore_normal_resume;
406 static int bounce_interval __read_mostly = DEFAULT_BOUNCE_INTERVAL;
408 static bool debug __read_mostly;
409 static bool smp __read_mostly;
410 static int apm_disabled = -1;
412 static bool power_off;
414 static bool power_off = 1;
416 static bool realmode_power_off;
417 #ifdef CONFIG_APM_ALLOW_INTS
418 static bool allow_ints = 1;
420 static bool allow_ints;
422 static bool broken_psr;
424 static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
425 static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
426 static struct apm_user *user_list;
427 static DEFINE_SPINLOCK(user_list_lock);
428 static DEFINE_MUTEX(apm_mutex);
431 * Set up a segment that references the real mode segment 0x40
432 * that extends up to the end of page zero (that we have reserved).
433 * This is for buggy BIOS's that refer to (real mode) segment 0x40
434 * even though they are called in protected mode.
436 static struct desc_struct bad_bios_desc = GDT_ENTRY_INIT(0x4092,
437 (unsigned long)__va(0x400UL), PAGE_SIZE - 0x400 - 1);
439 static const char driver_version[] = "1.16ac"; /* no spaces */
441 static struct task_struct *kapmd_task;
444 * APM event names taken from the APM 1.2 specification. These are
445 * the message codes that the BIOS uses to tell us about events
447 static const char * const apm_event_name[] = {
453 "power status change",
458 "system standby resume",
459 "capabilities change"
461 #define NR_APM_EVENT_NAME ARRAY_SIZE(apm_event_name)
463 typedef struct lookup_t {
469 * The BIOS returns a set of standard error codes in AX when the
473 static const lookup_t error_table[] = {
474 /* N/A { APM_SUCCESS, "Operation succeeded" }, */
475 { APM_DISABLED, "Power management disabled" },
476 { APM_CONNECTED, "Real mode interface already connected" },
477 { APM_NOT_CONNECTED, "Interface not connected" },
478 { APM_16_CONNECTED, "16 bit interface already connected" },
479 /* N/A { APM_16_UNSUPPORTED, "16 bit interface not supported" }, */
480 { APM_32_CONNECTED, "32 bit interface already connected" },
481 { APM_32_UNSUPPORTED, "32 bit interface not supported" },
482 { APM_BAD_DEVICE, "Unrecognized device ID" },
483 { APM_BAD_PARAM, "Parameter out of range" },
484 { APM_NOT_ENGAGED, "Interface not engaged" },
485 { APM_BAD_FUNCTION, "Function not supported" },
486 { APM_RESUME_DISABLED, "Resume timer disabled" },
487 { APM_BAD_STATE, "Unable to enter requested state" },
488 /* N/A { APM_NO_EVENTS, "No events pending" }, */
489 { APM_NO_ERROR, "BIOS did not set a return code" },
490 { APM_NOT_PRESENT, "No APM present" }
492 #define ERROR_COUNT ARRAY_SIZE(error_table)
495 * apm_error - display an APM error
496 * @str: information string
497 * @err: APM BIOS return code
499 * Write a meaningful log entry to the kernel log in the event of
500 * an APM error. Note that this also handles (negative) kernel errors.
503 static void apm_error(char *str, int err)
507 for (i = 0; i < ERROR_COUNT; i++)
508 if (error_table[i].key == err)
511 pr_notice("%s: %s\n", str, error_table[i].msg);
513 pr_notice("%s: linux error code %i\n", str, err);
515 pr_notice("%s: unknown error code %#2.2x\n",
520 * These are the actual BIOS calls. Depending on APM_ZERO_SEGS and
521 * apm_info.allow_ints, we are being really paranoid here! Not only
522 * are interrupts disabled, but all the segment registers (except SS)
523 * are saved and zeroed this means that if the BIOS tries to reference
524 * any data without explicitly loading the segment registers, the kernel
525 * will fault immediately rather than have some unforeseen circumstances
526 * for the rest of the kernel. And it will be very obvious! :-) Doing
527 * this depends on CS referring to the same physical memory as DS so that
528 * DS can be zeroed before the call. Unfortunately, we can't do anything
529 * about the stack segment/pointer. Also, we tell the compiler that
530 * everything could change.
532 * Also, we KNOW that for the non error case of apm_bios_call, there
533 * is no useful data returned in the low order 8 bits of eax.
536 static inline unsigned long __apm_irq_save(void)
539 local_save_flags(flags);
540 if (apm_info.allow_ints) {
541 if (irqs_disabled_flags(flags))
549 #define apm_irq_save(flags) \
550 do { flags = __apm_irq_save(); } while (0)
552 static inline void apm_irq_restore(unsigned long flags)
554 if (irqs_disabled_flags(flags))
556 else if (irqs_disabled())
561 # define APM_DECL_SEGS \
562 unsigned int saved_fs; unsigned int saved_gs;
563 # define APM_DO_SAVE_SEGS \
564 savesegment(fs, saved_fs); savesegment(gs, saved_gs)
565 # define APM_DO_RESTORE_SEGS \
566 loadsegment(fs, saved_fs); loadsegment(gs, saved_gs)
568 # define APM_DECL_SEGS
569 # define APM_DO_SAVE_SEGS
570 # define APM_DO_RESTORE_SEGS
573 struct apm_bios_call {
583 /* Error: -ENOMEM, or bits 8-15 of eax */
588 * __apm_bios_call - Make an APM BIOS 32bit call
589 * @_call: pointer to struct apm_bios_call.
591 * Make an APM call using the 32bit protected mode interface. The
592 * caller is responsible for knowing if APM BIOS is configured and
593 * enabled. This call can disable interrupts for a long period of
594 * time on some laptops. The return value is in AH and the carry
595 * flag is loaded into AL. If there is an error, then the error
596 * code is returned in AH (bits 8-15 of eax) and this function
599 * Note: this makes the call on the current CPU.
601 static long __apm_bios_call(void *_call)
606 struct desc_struct save_desc_40;
607 struct desc_struct *gdt;
608 struct apm_bios_call *call = _call;
612 gdt = get_cpu_gdt_table(cpu);
613 save_desc_40 = gdt[0x40 / 8];
614 gdt[0x40 / 8] = bad_bios_desc;
617 firmware_restrict_branch_speculation_start();
619 apm_bios_call_asm(call->func, call->ebx, call->ecx,
620 &call->eax, &call->ebx, &call->ecx, &call->edx,
623 firmware_restrict_branch_speculation_end();
624 apm_irq_restore(flags);
625 gdt[0x40 / 8] = save_desc_40;
628 return call->eax & 0xff;
631 /* Run __apm_bios_call or __apm_bios_call_simple on CPU 0 */
632 static int on_cpu0(long (*fn)(void *), struct apm_bios_call *call)
636 /* Don't bother with work_on_cpu in the common case, so we don't
637 * have to worry about OOM or overhead. */
638 if (get_cpu() == 0) {
643 ret = work_on_cpu(0, fn, call);
646 /* work_on_cpu can fail with -ENOMEM */
650 call->err = (call->eax >> 8) & 0xff;
656 * apm_bios_call - Make an APM BIOS 32bit call (on CPU 0)
657 * @call: the apm_bios_call registers.
659 * If there is an error, it is returned in @call.err.
661 static int apm_bios_call(struct apm_bios_call *call)
663 return on_cpu0(__apm_bios_call, call);
667 * __apm_bios_call_simple - Make an APM BIOS 32bit call (on CPU 0)
668 * @_call: pointer to struct apm_bios_call.
670 * Make a BIOS call that returns one value only, or just status.
671 * If there is an error, then the error code is returned in AH
672 * (bits 8-15 of eax) and this function returns non-zero (it can
673 * also return -ENOMEM). This is used for simpler BIOS operations.
674 * This call may hold interrupts off for a long time on some laptops.
676 * Note: this makes the call on the current CPU.
678 static long __apm_bios_call_simple(void *_call)
684 struct desc_struct save_desc_40;
685 struct desc_struct *gdt;
686 struct apm_bios_call *call = _call;
690 gdt = get_cpu_gdt_table(cpu);
691 save_desc_40 = gdt[0x40 / 8];
692 gdt[0x40 / 8] = bad_bios_desc;
695 firmware_restrict_branch_speculation_start();
697 error = apm_bios_call_simple_asm(call->func, call->ebx, call->ecx,
700 firmware_restrict_branch_speculation_end();
701 apm_irq_restore(flags);
702 gdt[0x40 / 8] = save_desc_40;
708 * apm_bios_call_simple - make a simple APM BIOS 32bit call
709 * @func: APM function to invoke
710 * @ebx_in: EBX register value for BIOS call
711 * @ecx_in: ECX register value for BIOS call
712 * @eax: EAX register on return from the BIOS call
715 * Make a BIOS call that returns one value only, or just status.
716 * If there is an error, then the error code is returned in @err
717 * and this function returns non-zero. This is used for simpler
718 * BIOS operations. This call may hold interrupts off for a long
719 * time on some laptops.
721 static int apm_bios_call_simple(u32 func, u32 ebx_in, u32 ecx_in, u32 *eax,
724 struct apm_bios_call call;
731 ret = on_cpu0(__apm_bios_call_simple, &call);
738 * apm_driver_version - APM driver version
739 * @val: loaded with the APM version on return
741 * Retrieve the APM version supported by the BIOS. This is only
742 * supported for APM 1.1 or higher. An error indicates APM 1.0 is
745 * On entry val should point to a value indicating the APM driver
746 * version with the high byte being the major and the low byte the
747 * minor number both in BCD
749 * On return it will hold the BIOS revision supported in the
753 static int apm_driver_version(u_short *val)
758 if (apm_bios_call_simple(APM_FUNC_VERSION, 0, *val, &eax, &err))
765 * apm_get_event - get an APM event from the BIOS
766 * @event: pointer to the event
767 * @info: point to the event information
769 * The APM BIOS provides a polled information for event
770 * reporting. The BIOS expects to be polled at least every second
771 * when events are pending. When a message is found the caller should
772 * poll until no more messages are present. However, this causes
773 * problems on some laptops where a suspend event notification is
774 * not cleared until it is acknowledged.
776 * Additional information is returned in the info pointer, providing
777 * that APM 1.2 is in use. If no messges are pending the value 0x80
778 * is returned (No power management events pending).
780 static int apm_get_event(apm_event_t *event, apm_eventinfo_t *info)
782 struct apm_bios_call call;
784 call.func = APM_FUNC_GET_EVENT;
785 call.ebx = call.ecx = 0;
787 if (apm_bios_call(&call))
791 if (apm_info.connection_version < 0x0102)
792 *info = ~0; /* indicate info not valid */
799 * set_power_state - set the power management state
800 * @what: which items to transition
801 * @state: state to transition to
803 * Request an APM change of state for one or more system devices. The
804 * processor state must be transitioned last of all. what holds the
805 * class of device in the upper byte and the device number (0xFF for
806 * all) for the object to be transitioned.
808 * The state holds the state to transition to, which may in fact
809 * be an acceptance of a BIOS requested state change.
812 static int set_power_state(u_short what, u_short state)
817 if (apm_bios_call_simple(APM_FUNC_SET_STATE, what, state, &eax, &err))
823 * set_system_power_state - set system wide power state
824 * @state: which state to enter
826 * Transition the entire system into a new APM power state.
829 static int set_system_power_state(u_short state)
831 return set_power_state(APM_DEVICE_ALL, state);
835 * apm_do_idle - perform power saving
837 * This function notifies the BIOS that the processor is (in the view
838 * of the OS) idle. It returns -1 in the event that the BIOS refuses
839 * to handle the idle request. On a success the function returns 1
840 * if the BIOS did clock slowing or 0 otherwise.
843 static int apm_do_idle(void)
850 if (!need_resched()) {
852 ret = apm_bios_call_simple(APM_FUNC_IDLE, 0, 0, &eax, &err);
859 static unsigned long t;
861 /* This always fails on some SMP boards running UP kernels.
862 * Only report the failure the first 5 times.
865 printk(KERN_DEBUG "apm_do_idle failed (%d)\n", err);
870 clock_slowed = (apm_info.bios.flags & APM_IDLE_SLOWS_CLOCK) != 0;
875 * apm_do_busy - inform the BIOS the CPU is busy
877 * Request that the BIOS brings the CPU back to full performance.
880 static void apm_do_busy(void)
885 if (clock_slowed || ALWAYS_CALL_BUSY) {
886 (void)apm_bios_call_simple(APM_FUNC_BUSY, 0, 0, &dummy, &err);
892 * If no process has really been interested in
893 * the CPU for some time, we want to call BIOS
894 * power management - we probably want
897 #define IDLE_CALC_LIMIT (HZ * 100)
898 #define IDLE_LEAKY_MAX 16
901 * apm_cpu_idle - cpu idling for APM capable Linux
903 * This is the idling function the kernel executes when APM is available. It
904 * tries to do BIOS powermanagement based on the average system idle time.
905 * Furthermore it calls the system default idle routine.
908 static int apm_cpu_idle(struct cpuidle_device *dev,
909 struct cpuidle_driver *drv, int index)
911 static int use_apm_idle; /* = 0 */
912 static unsigned int last_jiffies; /* = 0 */
913 static unsigned int last_stime; /* = 0 */
916 int apm_idle_done = 0;
917 unsigned int jiffies_since_last_check = jiffies - last_jiffies;
921 task_cputime(current, NULL, &stime);
922 if (jiffies_since_last_check > IDLE_CALC_LIMIT) {
924 } else if (jiffies_since_last_check > idle_period) {
925 unsigned int idle_percentage;
927 idle_percentage = cputime_to_jiffies(stime - last_stime);
928 idle_percentage *= 100;
929 idle_percentage /= jiffies_since_last_check;
930 use_apm_idle = (idle_percentage > idle_threshold);
931 if (apm_info.forbid_idle)
935 last_jiffies = jiffies;
938 bucket = IDLE_LEAKY_MAX;
940 while (!need_resched()) {
945 switch (apm_do_idle()) {
950 bucket = IDLE_LEAKY_MAX;
961 default: /* BIOS refused */
967 jiffies_since_last_check = jiffies - last_jiffies;
968 if (jiffies_since_last_check > idle_period)
979 * apm_power_off - ask the BIOS to power off
981 * Handle the power off sequence. This is the one piece of code we
982 * will execute even on SMP machines. In order to deal with BIOS
983 * bugs we support real mode APM BIOS power off calls. We also make
984 * the SMP call on CPU0 as some systems will only honour this call
985 * on their first cpu.
988 static void apm_power_off(void)
990 /* Some bioses don't like being called from CPU != 0 */
991 if (apm_info.realmode_power_off) {
992 set_cpus_allowed_ptr(current, cpumask_of(0));
993 machine_real_restart(MRR_APM);
995 (void)set_system_power_state(APM_STATE_OFF);
999 #ifdef CONFIG_APM_DO_ENABLE
1002 * apm_enable_power_management - enable BIOS APM power management
1003 * @enable: enable yes/no
1005 * Enable or disable the APM BIOS power services.
1008 static int apm_enable_power_management(int enable)
1013 if ((enable == 0) && (apm_info.bios.flags & APM_BIOS_DISENGAGED))
1014 return APM_NOT_ENGAGED;
1015 if (apm_bios_call_simple(APM_FUNC_ENABLE_PM, APM_DEVICE_BALL,
1016 enable, &eax, &err))
1019 apm_info.bios.flags &= ~APM_BIOS_DISABLED;
1021 apm_info.bios.flags |= APM_BIOS_DISABLED;
1027 * apm_get_power_status - get current power state
1028 * @status: returned status
1029 * @bat: battery info
1030 * @life: estimated life
1032 * Obtain the current power status from the APM BIOS. We return a
1033 * status which gives the rough battery status, and current power
1034 * source. The bat value returned give an estimate as a percentage
1035 * of life and a status value for the battery. The estimated life
1036 * if reported is a lifetime in secodnds/minutes at current powwer
1040 static int apm_get_power_status(u_short *status, u_short *bat, u_short *life)
1042 struct apm_bios_call call;
1044 call.func = APM_FUNC_GET_STATUS;
1045 call.ebx = APM_DEVICE_ALL;
1048 if (apm_info.get_power_status_broken)
1049 return APM_32_UNSUPPORTED;
1050 if (apm_bios_call(&call))
1054 if (apm_info.get_power_status_swabinminutes) {
1055 *life = swab16((u16)call.edx);
1063 static int apm_get_battery_status(u_short which, u_short *status,
1064 u_short *bat, u_short *life, u_short *nbat)
1072 if (apm_info.connection_version < 0x0102) {
1073 /* pretend we only have one battery. */
1075 return APM_BAD_DEVICE;
1077 return apm_get_power_status(status, bat, life);
1080 if (apm_bios_call(APM_FUNC_GET_STATUS, (0x8000 | (which)), 0, &eax,
1081 &ebx, &ecx, &edx, &esi))
1082 return (eax >> 8) & 0xff;
1092 * apm_engage_power_management - enable PM on a device
1093 * @device: identity of device
1096 * Activate or deactive power management on either a specific device
1097 * or the entire system (%APM_DEVICE_ALL).
1100 static int apm_engage_power_management(u_short device, int enable)
1105 if ((enable == 0) && (device == APM_DEVICE_ALL)
1106 && (apm_info.bios.flags & APM_BIOS_DISABLED))
1107 return APM_DISABLED;
1108 if (apm_bios_call_simple(APM_FUNC_ENGAGE_PM, device, enable,
1111 if (device == APM_DEVICE_ALL) {
1113 apm_info.bios.flags &= ~APM_BIOS_DISENGAGED;
1115 apm_info.bios.flags |= APM_BIOS_DISENGAGED;
1120 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1123 * apm_console_blank - blank the display
1126 * Attempt to blank the console, firstly by blanking just video device
1127 * zero, and if that fails (some BIOSes don't support it) then it blanks
1128 * all video devices. Typically the BIOS will do laptop backlight and
1129 * monitor powerdown for us.
1132 static int apm_console_blank(int blank)
1134 int error = APM_NOT_ENGAGED; /* silence gcc */
1137 static const u_short dev[3] = { 0x100, 0x1FF, 0x101 };
1139 state = blank ? APM_STATE_STANDBY : APM_STATE_READY;
1141 for (i = 0; i < ARRAY_SIZE(dev); i++) {
1142 error = set_power_state(dev[i], state);
1144 if ((error == APM_SUCCESS) || (error == APM_NO_ERROR))
1147 if (error == APM_NOT_ENGAGED)
1151 if (error == APM_NOT_ENGAGED) {
1155 eng_error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1157 apm_error("set display", error);
1158 apm_error("engage interface", eng_error);
1161 return apm_console_blank(blank);
1164 apm_error("set display", error);
1169 static int queue_empty(struct apm_user *as)
1171 return as->event_head == as->event_tail;
1174 static apm_event_t get_queued_event(struct apm_user *as)
1176 if (++as->event_tail >= APM_MAX_EVENTS)
1178 return as->events[as->event_tail];
1181 static void queue_event(apm_event_t event, struct apm_user *sender)
1183 struct apm_user *as;
1185 spin_lock(&user_list_lock);
1186 if (user_list == NULL)
1188 for (as = user_list; as != NULL; as = as->next) {
1189 if ((as == sender) || (!as->reader))
1191 if (++as->event_head >= APM_MAX_EVENTS)
1194 if (as->event_head == as->event_tail) {
1195 static int notified;
1197 if (notified++ == 0)
1198 pr_err("an event queue overflowed\n");
1199 if (++as->event_tail >= APM_MAX_EVENTS)
1202 as->events[as->event_head] = event;
1203 if (!as->suser || !as->writer)
1206 case APM_SYS_SUSPEND:
1207 case APM_USER_SUSPEND:
1208 as->suspends_pending++;
1212 case APM_SYS_STANDBY:
1213 case APM_USER_STANDBY:
1214 as->standbys_pending++;
1219 wake_up_interruptible(&apm_waitqueue);
1221 spin_unlock(&user_list_lock);
1224 static void reinit_timer(void)
1226 #ifdef INIT_TIMER_AFTER_SUSPEND
1227 unsigned long flags;
1229 raw_spin_lock_irqsave(&i8253_lock, flags);
1230 /* set the clock to HZ */
1231 outb_p(0x34, PIT_MODE); /* binary, mode 2, LSB/MSB, ch 0 */
1233 outb_p(LATCH & 0xff, PIT_CH0); /* LSB */
1235 outb_p(LATCH >> 8, PIT_CH0); /* MSB */
1237 raw_spin_unlock_irqrestore(&i8253_lock, flags);
1241 static int suspend(int vetoable)
1244 struct apm_user *as;
1246 dpm_suspend_start(PMSG_SUSPEND);
1247 dpm_suspend_end(PMSG_SUSPEND);
1249 local_irq_disable();
1254 save_processor_state();
1255 err = set_system_power_state(APM_STATE_SUSPEND);
1256 ignore_normal_resume = 1;
1257 restore_processor_state();
1259 local_irq_disable();
1262 if (err == APM_NO_ERROR)
1264 if (err != APM_SUCCESS)
1265 apm_error("suspend", err);
1266 err = (err == APM_SUCCESS) ? 0 : -EIO;
1271 dpm_resume_start(PMSG_RESUME);
1272 dpm_resume_end(PMSG_RESUME);
1274 queue_event(APM_NORMAL_RESUME, NULL);
1275 spin_lock(&user_list_lock);
1276 for (as = user_list; as != NULL; as = as->next) {
1277 as->suspend_wait = 0;
1278 as->suspend_result = err;
1280 spin_unlock(&user_list_lock);
1281 wake_up_interruptible(&apm_suspend_waitqueue);
1285 static void standby(void)
1289 dpm_suspend_end(PMSG_SUSPEND);
1291 local_irq_disable();
1295 err = set_system_power_state(APM_STATE_STANDBY);
1296 if ((err != APM_SUCCESS) && (err != APM_NO_ERROR))
1297 apm_error("standby", err);
1299 local_irq_disable();
1303 dpm_resume_start(PMSG_RESUME);
1306 static apm_event_t get_event(void)
1309 apm_event_t event = APM_NO_EVENTS; /* silence gcc */
1310 apm_eventinfo_t info;
1312 static int notified;
1314 /* we don't use the eventinfo */
1315 error = apm_get_event(&event, &info);
1316 if (error == APM_SUCCESS)
1319 if ((error != APM_NO_EVENTS) && (notified++ == 0))
1320 apm_error("get_event", error);
1325 static void check_events(void)
1328 static unsigned long last_resume;
1329 static int ignore_bounce;
1331 while ((event = get_event()) != 0) {
1333 if (event <= NR_APM_EVENT_NAME)
1334 printk(KERN_DEBUG "apm: received %s notify\n",
1335 apm_event_name[event - 1]);
1337 printk(KERN_DEBUG "apm: received unknown "
1338 "event 0x%02x\n", event);
1341 && (time_after(jiffies, last_resume + bounce_interval)))
1345 case APM_SYS_STANDBY:
1346 case APM_USER_STANDBY:
1347 queue_event(event, NULL);
1348 if (standbys_pending <= 0)
1352 case APM_USER_SUSPEND:
1353 #ifdef CONFIG_APM_IGNORE_USER_SUSPEND
1354 if (apm_info.connection_version > 0x100)
1355 set_system_power_state(APM_STATE_REJECT);
1358 case APM_SYS_SUSPEND:
1359 if (ignore_bounce) {
1360 if (apm_info.connection_version > 0x100)
1361 set_system_power_state(APM_STATE_REJECT);
1365 * If we are already processing a SUSPEND,
1366 * then further SUSPEND events from the BIOS
1367 * will be ignored. We also return here to
1368 * cope with the fact that the Thinkpads keep
1369 * sending a SUSPEND event until something else
1372 if (ignore_sys_suspend)
1374 ignore_sys_suspend = 1;
1375 queue_event(event, NULL);
1376 if (suspends_pending <= 0)
1380 case APM_NORMAL_RESUME:
1381 case APM_CRITICAL_RESUME:
1382 case APM_STANDBY_RESUME:
1383 ignore_sys_suspend = 0;
1384 last_resume = jiffies;
1386 if ((event != APM_NORMAL_RESUME)
1387 || (ignore_normal_resume == 0)) {
1388 dpm_resume_end(PMSG_RESUME);
1389 queue_event(event, NULL);
1391 ignore_normal_resume = 0;
1394 case APM_CAPABILITY_CHANGE:
1395 case APM_LOW_BATTERY:
1396 case APM_POWER_STATUS_CHANGE:
1397 queue_event(event, NULL);
1398 /* If needed, notify drivers here */
1401 case APM_UPDATE_TIME:
1404 case APM_CRITICAL_SUSPEND:
1406 * We are not allowed to reject a critical suspend.
1414 static void apm_event_handler(void)
1416 static int pending_count = 4;
1419 if ((standbys_pending > 0) || (suspends_pending > 0)) {
1420 if ((apm_info.connection_version > 0x100) &&
1421 (pending_count-- <= 0)) {
1424 printk(KERN_DEBUG "apm: setting state busy\n");
1425 err = set_system_power_state(APM_STATE_BUSY);
1427 apm_error("busy", err);
1435 * This is the APM thread main loop.
1438 static void apm_mainloop(void)
1440 DECLARE_WAITQUEUE(wait, current);
1442 add_wait_queue(&apm_waitqueue, &wait);
1443 set_current_state(TASK_INTERRUPTIBLE);
1445 schedule_timeout(APM_CHECK_TIMEOUT);
1446 if (kthread_should_stop())
1449 * Ok, check all events, check for idle (and mark us sleeping
1450 * so as not to count towards the load average)..
1452 set_current_state(TASK_INTERRUPTIBLE);
1453 apm_event_handler();
1455 remove_wait_queue(&apm_waitqueue, &wait);
1458 static int check_apm_user(struct apm_user *as, const char *func)
1460 if (as == NULL || as->magic != APM_BIOS_MAGIC) {
1461 pr_err("%s passed bad filp\n", func);
1467 static ssize_t do_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
1469 struct apm_user *as;
1473 as = fp->private_data;
1474 if (check_apm_user(as, "read"))
1476 if ((int)count < sizeof(apm_event_t))
1478 if ((queue_empty(as)) && (fp->f_flags & O_NONBLOCK))
1480 wait_event_interruptible(apm_waitqueue, !queue_empty(as));
1482 while ((i >= sizeof(event)) && !queue_empty(as)) {
1483 event = get_queued_event(as);
1484 if (copy_to_user(buf, &event, sizeof(event))) {
1490 case APM_SYS_SUSPEND:
1491 case APM_USER_SUSPEND:
1492 as->suspends_read++;
1495 case APM_SYS_STANDBY:
1496 case APM_USER_STANDBY:
1497 as->standbys_read++;
1500 buf += sizeof(event);
1505 if (signal_pending(current))
1506 return -ERESTARTSYS;
1510 static unsigned int do_poll(struct file *fp, poll_table *wait)
1512 struct apm_user *as;
1514 as = fp->private_data;
1515 if (check_apm_user(as, "poll"))
1517 poll_wait(fp, &apm_waitqueue, wait);
1518 if (!queue_empty(as))
1519 return POLLIN | POLLRDNORM;
1523 static long do_ioctl(struct file *filp, u_int cmd, u_long arg)
1525 struct apm_user *as;
1528 as = filp->private_data;
1529 if (check_apm_user(as, "ioctl"))
1531 if (!as->suser || !as->writer)
1534 case APM_IOC_STANDBY:
1535 mutex_lock(&apm_mutex);
1536 if (as->standbys_read > 0) {
1537 as->standbys_read--;
1538 as->standbys_pending--;
1541 queue_event(APM_USER_STANDBY, as);
1542 if (standbys_pending <= 0)
1544 mutex_unlock(&apm_mutex);
1546 case APM_IOC_SUSPEND:
1547 mutex_lock(&apm_mutex);
1548 if (as->suspends_read > 0) {
1549 as->suspends_read--;
1550 as->suspends_pending--;
1553 queue_event(APM_USER_SUSPEND, as);
1554 if (suspends_pending <= 0) {
1556 mutex_unlock(&apm_mutex);
1558 as->suspend_wait = 1;
1559 mutex_unlock(&apm_mutex);
1560 wait_event_interruptible(apm_suspend_waitqueue,
1561 as->suspend_wait == 0);
1562 ret = as->suspend_result;
1571 static int do_release(struct inode *inode, struct file *filp)
1573 struct apm_user *as;
1575 as = filp->private_data;
1576 if (check_apm_user(as, "release"))
1578 filp->private_data = NULL;
1579 if (as->standbys_pending > 0) {
1580 standbys_pending -= as->standbys_pending;
1581 if (standbys_pending <= 0)
1584 if (as->suspends_pending > 0) {
1585 suspends_pending -= as->suspends_pending;
1586 if (suspends_pending <= 0)
1589 spin_lock(&user_list_lock);
1590 if (user_list == as)
1591 user_list = as->next;
1593 struct apm_user *as1;
1595 for (as1 = user_list;
1596 (as1 != NULL) && (as1->next != as);
1600 pr_err("filp not in user list\n");
1602 as1->next = as->next;
1604 spin_unlock(&user_list_lock);
1609 static int do_open(struct inode *inode, struct file *filp)
1611 struct apm_user *as;
1613 as = kmalloc(sizeof(*as), GFP_KERNEL);
1617 as->magic = APM_BIOS_MAGIC;
1618 as->event_tail = as->event_head = 0;
1619 as->suspends_pending = as->standbys_pending = 0;
1620 as->suspends_read = as->standbys_read = 0;
1622 * XXX - this is a tiny bit broken, when we consider BSD
1623 * process accounting. If the device is opened by root, we
1624 * instantly flag that we used superuser privs. Who knows,
1625 * we might close the device immediately without doing a
1626 * privileged operation -- cevans
1628 as->suser = capable(CAP_SYS_ADMIN);
1629 as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
1630 as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
1631 spin_lock(&user_list_lock);
1632 as->next = user_list;
1634 spin_unlock(&user_list_lock);
1635 filp->private_data = as;
1639 static int proc_apm_show(struct seq_file *m, void *v)
1645 unsigned short ac_line_status = 0xff;
1646 unsigned short battery_status = 0xff;
1647 unsigned short battery_flag = 0xff;
1648 int percentage = -1;
1649 int time_units = -1;
1652 if ((num_online_cpus() == 1) &&
1653 !(error = apm_get_power_status(&bx, &cx, &dx))) {
1654 ac_line_status = (bx >> 8) & 0xff;
1655 battery_status = bx & 0xff;
1656 if ((cx & 0xff) != 0xff)
1657 percentage = cx & 0xff;
1659 if (apm_info.connection_version > 0x100) {
1660 battery_flag = (cx >> 8) & 0xff;
1662 units = (dx & 0x8000) ? "min" : "sec";
1663 time_units = dx & 0x7fff;
1667 /* Arguments, with symbols from linux/apm_bios.h. Information is
1668 from the Get Power Status (0x0a) call unless otherwise noted.
1670 0) Linux driver version (this will change if format changes)
1671 1) APM BIOS Version. Usually 1.0, 1.1 or 1.2.
1672 2) APM flags from APM Installation Check (0x00):
1673 bit 0: APM_16_BIT_SUPPORT
1674 bit 1: APM_32_BIT_SUPPORT
1675 bit 2: APM_IDLE_SLOWS_CLOCK
1676 bit 3: APM_BIOS_DISABLED
1677 bit 4: APM_BIOS_DISENGAGED
1681 0x02: On backup power (BIOS >= 1.1 only)
1688 0x04: Selected battery not present (BIOS >= 1.2 only)
1695 bit 7: No system battery
1697 6) Remaining battery life (percentage of charge):
1700 7) Remaining battery life (time units):
1701 Number of remaining minutes or seconds
1703 8) min = minutes; sec = seconds */
1705 seq_printf(m, "%s %d.%d 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
1707 (apm_info.bios.version >> 8) & 0xff,
1708 apm_info.bios.version & 0xff,
1709 apm_info.bios.flags,
1719 static int proc_apm_open(struct inode *inode, struct file *file)
1721 return single_open(file, proc_apm_show, NULL);
1724 static const struct file_operations apm_file_ops = {
1725 .owner = THIS_MODULE,
1726 .open = proc_apm_open,
1728 .llseek = seq_lseek,
1729 .release = single_release,
1732 static int apm(void *unused)
1742 * This is to avoid random crashes at boot time during initialization
1743 * on SMP systems in case of "apm=power-off" mode. Seen on ASUS A7M266D.
1744 * Some bioses don't like being called from CPU != 0.
1745 * Method suggested by Ingo Molnar.
1747 set_cpus_allowed_ptr(current, cpumask_of(0));
1748 BUG_ON(smp_processor_id() != 0);
1750 if (apm_info.connection_version == 0) {
1751 apm_info.connection_version = apm_info.bios.version;
1752 if (apm_info.connection_version > 0x100) {
1754 * We only support BIOSs up to version 1.2
1756 if (apm_info.connection_version > 0x0102)
1757 apm_info.connection_version = 0x0102;
1758 error = apm_driver_version(&apm_info.connection_version);
1759 if (error != APM_SUCCESS) {
1760 apm_error("driver version", error);
1761 /* Fall back to an APM 1.0 connection. */
1762 apm_info.connection_version = 0x100;
1768 printk(KERN_INFO "apm: Connection version %d.%d\n",
1769 (apm_info.connection_version >> 8) & 0xff,
1770 apm_info.connection_version & 0xff);
1772 #ifdef CONFIG_APM_DO_ENABLE
1773 if (apm_info.bios.flags & APM_BIOS_DISABLED) {
1775 * This call causes my NEC UltraLite Versa 33/C to hang if it
1776 * is booted with PM disabled but not in the docking station.
1779 error = apm_enable_power_management(1);
1781 apm_error("enable power management", error);
1787 if ((apm_info.bios.flags & APM_BIOS_DISENGAGED)
1788 && (apm_info.connection_version > 0x0100)) {
1789 error = apm_engage_power_management(APM_DEVICE_ALL, 1);
1791 apm_error("engage power management", error);
1796 if (debug && (num_online_cpus() == 1 || smp)) {
1797 error = apm_get_power_status(&bx, &cx, &dx);
1799 printk(KERN_INFO "apm: power status not available\n");
1801 switch ((bx >> 8) & 0xff) {
1803 power_stat = "off line";
1806 power_stat = "on line";
1809 power_stat = "on backup power";
1812 power_stat = "unknown";
1815 switch (bx & 0xff) {
1823 bat_stat = "critical";
1826 bat_stat = "charging";
1829 bat_stat = "unknown";
1833 "apm: AC %s, battery status %s, battery life ",
1834 power_stat, bat_stat);
1835 if ((cx & 0xff) == 0xff)
1836 printk("unknown\n");
1838 printk("%d%%\n", cx & 0xff);
1839 if (apm_info.connection_version > 0x100) {
1841 "apm: battery flag 0x%02x, battery life ",
1844 printk("unknown\n");
1846 printk("%d %s\n", dx & 0x7fff,
1848 "minutes" : "seconds");
1853 /* Install our power off handler.. */
1855 pm_power_off = apm_power_off;
1857 if (num_online_cpus() == 1 || smp) {
1858 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1859 console_blank_hook = apm_console_blank;
1862 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
1863 console_blank_hook = NULL;
1871 static int __init apm_setup(char *str)
1875 while ((str != NULL) && (*str != '\0')) {
1876 if (strncmp(str, "off", 3) == 0)
1878 if (strncmp(str, "on", 2) == 0)
1880 if ((strncmp(str, "bounce-interval=", 16) == 0) ||
1881 (strncmp(str, "bounce_interval=", 16) == 0))
1882 bounce_interval = simple_strtol(str + 16, NULL, 0);
1883 if ((strncmp(str, "idle-threshold=", 15) == 0) ||
1884 (strncmp(str, "idle_threshold=", 15) == 0))
1885 idle_threshold = simple_strtol(str + 15, NULL, 0);
1886 if ((strncmp(str, "idle-period=", 12) == 0) ||
1887 (strncmp(str, "idle_period=", 12) == 0))
1888 idle_period = simple_strtol(str + 12, NULL, 0);
1889 invert = (strncmp(str, "no-", 3) == 0) ||
1890 (strncmp(str, "no_", 3) == 0);
1893 if (strncmp(str, "debug", 5) == 0)
1895 if ((strncmp(str, "power-off", 9) == 0) ||
1896 (strncmp(str, "power_off", 9) == 0))
1897 power_off = !invert;
1898 if (strncmp(str, "smp", 3) == 0) {
1900 idle_threshold = 100;
1902 if ((strncmp(str, "allow-ints", 10) == 0) ||
1903 (strncmp(str, "allow_ints", 10) == 0))
1904 apm_info.allow_ints = !invert;
1905 if ((strncmp(str, "broken-psr", 10) == 0) ||
1906 (strncmp(str, "broken_psr", 10) == 0))
1907 apm_info.get_power_status_broken = !invert;
1908 if ((strncmp(str, "realmode-power-off", 18) == 0) ||
1909 (strncmp(str, "realmode_power_off", 18) == 0))
1910 apm_info.realmode_power_off = !invert;
1911 str = strchr(str, ',');
1913 str += strspn(str, ", \t");
1918 __setup("apm=", apm_setup);
1921 static const struct file_operations apm_bios_fops = {
1922 .owner = THIS_MODULE,
1925 .unlocked_ioctl = do_ioctl,
1927 .release = do_release,
1928 .llseek = noop_llseek,
1931 static struct miscdevice apm_device = {
1938 /* Simple "print if true" callback */
1939 static int __init print_if_true(const struct dmi_system_id *d)
1941 printk("%s\n", d->ident);
1946 * Some Bioses enable the PS/2 mouse (touchpad) at resume, even if it was
1947 * disabled before the suspend. Linux used to get terribly confused by that.
1949 static int __init broken_ps2_resume(const struct dmi_system_id *d)
1951 printk(KERN_INFO "%s machine detected. Mousepad Resume Bug "
1952 "workaround hopefully not needed.\n", d->ident);
1956 /* Some bioses have a broken protected mode poweroff and need to use realmode */
1957 static int __init set_realmode_power_off(const struct dmi_system_id *d)
1959 if (apm_info.realmode_power_off == 0) {
1960 apm_info.realmode_power_off = 1;
1961 printk(KERN_INFO "%s bios detected. "
1962 "Using realmode poweroff only.\n", d->ident);
1967 /* Some laptops require interrupts to be enabled during APM calls */
1968 static int __init set_apm_ints(const struct dmi_system_id *d)
1970 if (apm_info.allow_ints == 0) {
1971 apm_info.allow_ints = 1;
1972 printk(KERN_INFO "%s machine detected. "
1973 "Enabling interrupts during APM calls.\n", d->ident);
1978 /* Some APM bioses corrupt memory or just plain do not work */
1979 static int __init apm_is_horked(const struct dmi_system_id *d)
1981 if (apm_info.disabled == 0) {
1982 apm_info.disabled = 1;
1983 printk(KERN_INFO "%s machine detected. "
1984 "Disabling APM.\n", d->ident);
1989 static int __init apm_is_horked_d850md(const struct dmi_system_id *d)
1991 if (apm_info.disabled == 0) {
1992 apm_info.disabled = 1;
1993 printk(KERN_INFO "%s machine detected. "
1994 "Disabling APM.\n", d->ident);
1995 printk(KERN_INFO "This bug is fixed in bios P15 which is available for\n");
1996 printk(KERN_INFO "download from support.intel.com\n");
2001 /* Some APM bioses hang on APM idle calls */
2002 static int __init apm_likes_to_melt(const struct dmi_system_id *d)
2004 if (apm_info.forbid_idle == 0) {
2005 apm_info.forbid_idle = 1;
2006 printk(KERN_INFO "%s machine detected. "
2007 "Disabling APM idle calls.\n", d->ident);
2013 * Check for clue free BIOS implementations who use
2014 * the following QA technique
2016 * [ Write BIOS Code ]<------
2018 * < Does it Compile >----N--
2020 * < Does it Boot Win98 >-N--
2024 * Phoenix A04 08/24/2000 is known bad (Dell Inspiron 5000e)
2025 * Phoenix A07 09/29/2000 is known good (Dell Inspiron 5000)
2027 static int __init broken_apm_power(const struct dmi_system_id *d)
2029 apm_info.get_power_status_broken = 1;
2030 printk(KERN_WARNING "BIOS strings suggest APM bugs, "
2031 "disabling power status reporting.\n");
2036 * This bios swaps the APM minute reporting bytes over (Many sony laptops
2037 * have this problem).
2039 static int __init swab_apm_power_in_minutes(const struct dmi_system_id *d)
2041 apm_info.get_power_status_swabinminutes = 1;
2042 printk(KERN_WARNING "BIOS strings suggest APM reports battery life "
2043 "in minutes and wrong byte order.\n");
2047 static struct dmi_system_id __initdata apm_dmi_table[] = {
2050 KERN_WARNING "IBM T23 - BIOS 1.03b+ and controller firmware 1.02+ may be needed for Linux APM.",
2051 { DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
2052 DMI_MATCH(DMI_BIOS_VERSION, "1AET38WW (1.01b)"), },
2054 { /* Handle problems with APM on the C600 */
2055 broken_ps2_resume, "Dell Latitude C600",
2056 { DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
2057 DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C600"), },
2059 { /* Allow interrupts during suspend on Dell Latitude laptops*/
2060 set_apm_ints, "Dell Latitude",
2061 { DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2062 DMI_MATCH(DMI_PRODUCT_NAME, "Latitude C510"), }
2065 apm_is_horked, "Dell Inspiron 2500",
2066 { DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2067 DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2068 DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2069 DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2071 { /* Allow interrupts during suspend on Dell Inspiron laptops*/
2072 set_apm_ints, "Dell Inspiron", {
2073 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2074 DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 4000"), },
2076 { /* Handle problems with APM on Inspiron 5000e */
2077 broken_apm_power, "Dell Inspiron 5000e",
2078 { DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2079 DMI_MATCH(DMI_BIOS_VERSION, "A04"),
2080 DMI_MATCH(DMI_BIOS_DATE, "08/24/2000"), },
2082 { /* Handle problems with APM on Inspiron 2500 */
2083 broken_apm_power, "Dell Inspiron 2500",
2084 { DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2085 DMI_MATCH(DMI_BIOS_VERSION, "A12"),
2086 DMI_MATCH(DMI_BIOS_DATE, "02/04/2002"), },
2089 apm_is_horked, "Dell Dimension 4100",
2090 { DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2091 DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"),
2092 DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2093 DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2095 { /* Allow interrupts during suspend on Compaq Laptops*/
2096 set_apm_ints, "Compaq 12XL125",
2097 { DMI_MATCH(DMI_SYS_VENDOR, "Compaq"),
2098 DMI_MATCH(DMI_PRODUCT_NAME, "Compaq PC"),
2099 DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2100 DMI_MATCH(DMI_BIOS_VERSION, "4.06"), },
2102 { /* Allow interrupts during APM or the clock goes slow */
2103 set_apm_ints, "ASUSTeK",
2104 { DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
2105 DMI_MATCH(DMI_PRODUCT_NAME, "L8400K series Notebook PC"), },
2107 { /* APM blows on shutdown */
2108 apm_is_horked, "ABIT KX7-333[R]",
2109 { DMI_MATCH(DMI_BOARD_VENDOR, "ABIT"),
2110 DMI_MATCH(DMI_BOARD_NAME, "VT8367-8233A (KX7-333[R])"), },
2113 apm_is_horked, "Trigem Delhi3",
2114 { DMI_MATCH(DMI_SYS_VENDOR, "TriGem Computer, Inc"),
2115 DMI_MATCH(DMI_PRODUCT_NAME, "Delhi3"), },
2118 apm_is_horked, "Fujitsu-Siemens",
2119 { DMI_MATCH(DMI_BIOS_VENDOR, "hoenix/FUJITSU SIEMENS"),
2120 DMI_MATCH(DMI_BIOS_VERSION, "Version1.01"), },
2123 apm_is_horked_d850md, "Intel D850MD",
2124 { DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2125 DMI_MATCH(DMI_BIOS_VERSION, "MV85010A.86A.0016.P07.0201251536"), },
2128 apm_is_horked, "Intel D810EMO",
2129 { DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2130 DMI_MATCH(DMI_BIOS_VERSION, "MO81010A.86A.0008.P04.0004170800"), },
2133 apm_is_horked, "Dell XPS-Z",
2134 { DMI_MATCH(DMI_BIOS_VENDOR, "Intel Corp."),
2135 DMI_MATCH(DMI_BIOS_VERSION, "A11"),
2136 DMI_MATCH(DMI_PRODUCT_NAME, "XPS-Z"), },
2139 apm_is_horked, "Sharp PC-PJ/AX",
2140 { DMI_MATCH(DMI_SYS_VENDOR, "SHARP"),
2141 DMI_MATCH(DMI_PRODUCT_NAME, "PC-PJ/AX"),
2142 DMI_MATCH(DMI_BIOS_VENDOR, "SystemSoft"),
2143 DMI_MATCH(DMI_BIOS_VERSION, "Version R2.08"), },
2146 apm_is_horked, "Dell Inspiron 2500",
2147 { DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
2148 DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 2500"),
2149 DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2150 DMI_MATCH(DMI_BIOS_VERSION, "A11"), },
2152 { /* APM idle hangs */
2153 apm_likes_to_melt, "Jabil AMD",
2154 { DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2155 DMI_MATCH(DMI_BIOS_VERSION, "0AASNP06"), },
2157 { /* APM idle hangs */
2158 apm_likes_to_melt, "AMI Bios",
2159 { DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
2160 DMI_MATCH(DMI_BIOS_VERSION, "0AASNP05"), },
2162 { /* Handle problems with APM on Sony Vaio PCG-N505X(DE) */
2163 swab_apm_power_in_minutes, "Sony VAIO",
2164 { DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2165 DMI_MATCH(DMI_BIOS_VERSION, "R0206H"),
2166 DMI_MATCH(DMI_BIOS_DATE, "08/23/99"), },
2168 { /* Handle problems with APM on Sony Vaio PCG-N505VX */
2169 swab_apm_power_in_minutes, "Sony VAIO",
2170 { DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2171 DMI_MATCH(DMI_BIOS_VERSION, "W2K06H0"),
2172 DMI_MATCH(DMI_BIOS_DATE, "02/03/00"), },
2174 { /* Handle problems with APM on Sony Vaio PCG-XG29 */
2175 swab_apm_power_in_minutes, "Sony VAIO",
2176 { DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2177 DMI_MATCH(DMI_BIOS_VERSION, "R0117A0"),
2178 DMI_MATCH(DMI_BIOS_DATE, "04/25/00"), },
2180 { /* Handle problems with APM on Sony Vaio PCG-Z600NE */
2181 swab_apm_power_in_minutes, "Sony VAIO",
2182 { DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2183 DMI_MATCH(DMI_BIOS_VERSION, "R0121Z1"),
2184 DMI_MATCH(DMI_BIOS_DATE, "05/11/00"), },
2186 { /* Handle problems with APM on Sony Vaio PCG-Z600NE */
2187 swab_apm_power_in_minutes, "Sony VAIO",
2188 { DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2189 DMI_MATCH(DMI_BIOS_VERSION, "WME01Z1"),
2190 DMI_MATCH(DMI_BIOS_DATE, "08/11/00"), },
2192 { /* Handle problems with APM on Sony Vaio PCG-Z600LEK(DE) */
2193 swab_apm_power_in_minutes, "Sony VAIO",
2194 { DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2195 DMI_MATCH(DMI_BIOS_VERSION, "R0206Z3"),
2196 DMI_MATCH(DMI_BIOS_DATE, "12/25/00"), },
2198 { /* Handle problems with APM on Sony Vaio PCG-Z505LS */
2199 swab_apm_power_in_minutes, "Sony VAIO",
2200 { DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2201 DMI_MATCH(DMI_BIOS_VERSION, "R0203D0"),
2202 DMI_MATCH(DMI_BIOS_DATE, "05/12/00"), },
2204 { /* Handle problems with APM on Sony Vaio PCG-Z505LS */
2205 swab_apm_power_in_minutes, "Sony VAIO",
2206 { DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2207 DMI_MATCH(DMI_BIOS_VERSION, "R0203Z3"),
2208 DMI_MATCH(DMI_BIOS_DATE, "08/25/00"), },
2210 { /* Handle problems with APM on Sony Vaio PCG-Z505LS (with updated BIOS) */
2211 swab_apm_power_in_minutes, "Sony VAIO",
2212 { DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2213 DMI_MATCH(DMI_BIOS_VERSION, "R0209Z3"),
2214 DMI_MATCH(DMI_BIOS_DATE, "05/12/01"), },
2216 { /* Handle problems with APM on Sony Vaio PCG-F104K */
2217 swab_apm_power_in_minutes, "Sony VAIO",
2218 { DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2219 DMI_MATCH(DMI_BIOS_VERSION, "R0204K2"),
2220 DMI_MATCH(DMI_BIOS_DATE, "08/28/00"), },
2223 { /* Handle problems with APM on Sony Vaio PCG-C1VN/C1VE */
2224 swab_apm_power_in_minutes, "Sony VAIO",
2225 { DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2226 DMI_MATCH(DMI_BIOS_VERSION, "R0208P1"),
2227 DMI_MATCH(DMI_BIOS_DATE, "11/09/00"), },
2229 { /* Handle problems with APM on Sony Vaio PCG-C1VE */
2230 swab_apm_power_in_minutes, "Sony VAIO",
2231 { DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2232 DMI_MATCH(DMI_BIOS_VERSION, "R0204P1"),
2233 DMI_MATCH(DMI_BIOS_DATE, "09/12/00"), },
2235 { /* Handle problems with APM on Sony Vaio PCG-C1VE */
2236 swab_apm_power_in_minutes, "Sony VAIO",
2237 { DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
2238 DMI_MATCH(DMI_BIOS_VERSION, "WXPO1Z3"),
2239 DMI_MATCH(DMI_BIOS_DATE, "10/26/01"), },
2241 { /* broken PM poweroff bios */
2242 set_realmode_power_off, "Award Software v4.60 PGMA",
2243 { DMI_MATCH(DMI_BIOS_VENDOR, "Award Software International, Inc."),
2244 DMI_MATCH(DMI_BIOS_VERSION, "4.60 PGMA"),
2245 DMI_MATCH(DMI_BIOS_DATE, "134526184"), },
2248 /* Generic per vendor APM settings */
2250 { /* Allow interrupts during suspend on IBM laptops */
2251 set_apm_ints, "IBM",
2252 { DMI_MATCH(DMI_SYS_VENDOR, "IBM"), },
2259 * Just start the APM thread. We do NOT want to do APM BIOS
2260 * calls from anything but the APM thread, if for no other reason
2261 * than the fact that we don't trust the APM BIOS. This way,
2262 * most common APM BIOS problems that lead to protection errors
2263 * etc will have at least some level of being contained...
2265 * In short, if something bad happens, at least we have a choice
2266 * of just killing the apm thread..
2268 static int __init apm_init(void)
2270 struct desc_struct *gdt;
2273 dmi_check_system(apm_dmi_table);
2275 if (apm_info.bios.version == 0 || paravirt_enabled() || machine_is_olpc()) {
2276 printk(KERN_INFO "apm: BIOS not found.\n");
2280 "apm: BIOS version %d.%d Flags 0x%02x (Driver version %s)\n",
2281 ((apm_info.bios.version >> 8) & 0xff),
2282 (apm_info.bios.version & 0xff),
2283 apm_info.bios.flags,
2285 if ((apm_info.bios.flags & APM_32_BIT_SUPPORT) == 0) {
2286 printk(KERN_INFO "apm: no 32 bit BIOS support\n");
2291 apm_info.allow_ints = 1;
2293 apm_info.get_power_status_broken = 1;
2294 if (realmode_power_off)
2295 apm_info.realmode_power_off = 1;
2296 /* User can override, but default is to trust DMI */
2297 if (apm_disabled != -1)
2298 apm_info.disabled = apm_disabled;
2301 * Fix for the Compaq Contura 3/25c which reports BIOS version 0.1
2302 * but is reportedly a 1.0 BIOS.
2304 if (apm_info.bios.version == 0x001)
2305 apm_info.bios.version = 0x100;
2307 /* BIOS < 1.2 doesn't set cseg_16_len */
2308 if (apm_info.bios.version < 0x102)
2309 apm_info.bios.cseg_16_len = 0; /* 64k */
2312 printk(KERN_INFO "apm: entry %x:%x cseg16 %x dseg %x",
2313 apm_info.bios.cseg, apm_info.bios.offset,
2314 apm_info.bios.cseg_16, apm_info.bios.dseg);
2315 if (apm_info.bios.version > 0x100)
2316 printk(" cseg len %x, dseg len %x",
2317 apm_info.bios.cseg_len,
2318 apm_info.bios.dseg_len);
2319 if (apm_info.bios.version > 0x101)
2320 printk(" cseg16 len %x", apm_info.bios.cseg_16_len);
2324 if (apm_info.disabled) {
2325 pr_notice("disabled on user request.\n");
2328 if ((num_online_cpus() > 1) && !power_off && !smp) {
2329 pr_notice("disabled - APM is not SMP safe.\n");
2330 apm_info.disabled = 1;
2333 if (!acpi_disabled) {
2334 pr_notice("overridden by ACPI.\n");
2335 apm_info.disabled = 1;
2340 * Set up the long jump entry point to the APM BIOS, which is called
2341 * from inline assembly.
2343 apm_bios_entry.offset = apm_info.bios.offset;
2344 apm_bios_entry.segment = APM_CS;
2347 * The APM 1.1 BIOS is supposed to provide limit information that it
2348 * recognizes. Many machines do this correctly, but many others do
2349 * not restrict themselves to their claimed limit. When this happens,
2350 * they will cause a segmentation violation in the kernel at boot time.
2351 * Most BIOS's, however, will respect a 64k limit, so we use that.
2353 * Note we only set APM segments on CPU zero, since we pin the APM
2356 gdt = get_cpu_gdt_table(0);
2357 set_desc_base(&gdt[APM_CS >> 3],
2358 (unsigned long)__va((unsigned long)apm_info.bios.cseg << 4));
2359 set_desc_base(&gdt[APM_CS_16 >> 3],
2360 (unsigned long)__va((unsigned long)apm_info.bios.cseg_16 << 4));
2361 set_desc_base(&gdt[APM_DS >> 3],
2362 (unsigned long)__va((unsigned long)apm_info.bios.dseg << 4));
2364 proc_create("apm", 0, NULL, &apm_file_ops);
2366 kapmd_task = kthread_create(apm, NULL, "kapmd");
2367 if (IS_ERR(kapmd_task)) {
2368 pr_err("disabled - Unable to start kernel thread\n");
2369 err = PTR_ERR(kapmd_task);
2371 remove_proc_entry("apm", NULL);
2374 wake_up_process(kapmd_task);
2376 if (num_online_cpus() > 1 && !smp) {
2378 "apm: disabled - APM is not SMP safe (power off active).\n");
2383 * Note we don't actually care if the misc_device cannot be registered.
2384 * this driver can do its job without it, even if userspace can't
2385 * control it. just log the error
2387 if (misc_register(&apm_device))
2388 printk(KERN_WARNING "apm: Could not register misc device.\n");
2391 idle_period = (idle_period * HZ) / 100;
2392 if (idle_threshold < 100) {
2393 if (!cpuidle_register_driver(&apm_idle_driver))
2394 if (cpuidle_register_device(&apm_cpuidle_device))
2395 cpuidle_unregister_driver(&apm_idle_driver);
2401 static void __exit apm_exit(void)
2405 cpuidle_unregister_device(&apm_cpuidle_device);
2406 cpuidle_unregister_driver(&apm_idle_driver);
2408 if (((apm_info.bios.flags & APM_BIOS_DISENGAGED) == 0)
2409 && (apm_info.connection_version > 0x0100)) {
2410 error = apm_engage_power_management(APM_DEVICE_ALL, 0);
2412 apm_error("disengage power management", error);
2414 misc_deregister(&apm_device);
2415 remove_proc_entry("apm", NULL);
2417 pm_power_off = NULL;
2419 kthread_stop(kapmd_task);
2424 module_init(apm_init);
2425 module_exit(apm_exit);
2427 MODULE_AUTHOR("Stephen Rothwell");
2428 MODULE_DESCRIPTION("Advanced Power Management");
2429 MODULE_LICENSE("GPL");
2430 module_param(debug, bool, 0644);
2431 MODULE_PARM_DESC(debug, "Enable debug mode");
2432 module_param(power_off, bool, 0444);
2433 MODULE_PARM_DESC(power_off, "Enable power off");
2434 module_param(bounce_interval, int, 0444);
2435 MODULE_PARM_DESC(bounce_interval,
2436 "Set the number of ticks to ignore suspend bounces");
2437 module_param(allow_ints, bool, 0444);
2438 MODULE_PARM_DESC(allow_ints, "Allow interrupts during BIOS calls");
2439 module_param(broken_psr, bool, 0444);
2440 MODULE_PARM_DESC(broken_psr, "BIOS has a broken GetPowerStatus call");
2441 module_param(realmode_power_off, bool, 0444);
2442 MODULE_PARM_DESC(realmode_power_off,
2443 "Switch to real mode before powering off");
2444 module_param(idle_threshold, int, 0444);
2445 MODULE_PARM_DESC(idle_threshold,
2446 "System idle percentage above which to make APM BIOS idle calls");
2447 module_param(idle_period, int, 0444);
2448 MODULE_PARM_DESC(idle_period,
2449 "Period (in sec/100) over which to caculate the idle percentage");
2450 module_param(smp, bool, 0444);
2451 MODULE_PARM_DESC(smp,
2452 "Set this to enable APM use on an SMP platform. Use with caution on older systems");
2453 MODULE_ALIAS_MISCDEV(APM_MINOR_DEV);