2 * processor_idle - idle state submodule to the ACPI processor driver
4 * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6 * Copyright (C) 2004 Dominik Brodowski <linux@brodo.de>
7 * Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
8 * - Added processor hotplug support
9 * Copyright (C) 2005 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
10 * - Added support for C3 on SMP
12 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or (at
17 * your option) any later version.
19 * This program is distributed in the hope that it will be useful, but
20 * WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22 * General Public License for more details.
24 * You should have received a copy of the GNU General Public License along
25 * with this program; if not, write to the Free Software Foundation, Inc.,
26 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
28 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
31 #include <linux/kernel.h>
32 #include <linux/module.h>
33 #include <linux/init.h>
34 #include <linux/cpufreq.h>
35 #include <linux/proc_fs.h>
36 #include <linux/seq_file.h>
37 #include <linux/acpi.h>
38 #include <linux/dmi.h>
39 #include <linux/moduleparam.h>
40 #include <linux/sched.h> /* need_resched() */
43 #include <asm/uaccess.h>
45 #include <acpi/acpi_bus.h>
46 #include <acpi/processor.h>
48 #define ACPI_PROCESSOR_COMPONENT 0x01000000
49 #define ACPI_PROCESSOR_CLASS "processor"
50 #define ACPI_PROCESSOR_DRIVER_NAME "ACPI Processor Driver"
51 #define _COMPONENT ACPI_PROCESSOR_COMPONENT
52 ACPI_MODULE_NAME("acpi_processor")
53 #define ACPI_PROCESSOR_FILE_POWER "power"
54 #define US_TO_PM_TIMER_TICKS(t) ((t * (PM_TIMER_FREQUENCY/1000)) / 1000)
55 #define C2_OVERHEAD 4 /* 1us (3.579 ticks per us) */
56 #define C3_OVERHEAD 4 /* 1us (3.579 ticks per us) */
57 static void (*pm_idle_save) (void);
58 module_param(max_cstate, uint, 0644);
60 static unsigned int nocst = 0;
61 module_param(nocst, uint, 0000);
64 * bm_history -- bit-mask with a bit per jiffy of bus-master activity
65 * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
66 * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
67 * 100 HZ: 0x0000000F: 4 jiffies = 40ms
68 * reduce history for more aggressive entry into C3
70 static unsigned int bm_history =
71 (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
72 module_param(bm_history, uint, 0644);
73 /* --------------------------------------------------------------------------
75 -------------------------------------------------------------------------- */
78 * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
79 * For now disable this. Probably a bug somewhere else.
81 * To skip this limit, boot/load with a large max_cstate limit.
83 static int set_max_cstate(struct dmi_system_id *id)
85 if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
88 printk(KERN_NOTICE PREFIX "%s detected - limiting to C%ld max_cstate."
89 " Override with \"processor.max_cstate=%d\"\n", id->ident,
90 (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
92 max_cstate = (long)id->driver_data;
97 static struct dmi_system_id __initdata processor_power_dmi_table[] = {
98 {set_max_cstate, "IBM ThinkPad R40e", {
99 DMI_MATCH(DMI_BIOS_VENDOR,
101 DMI_MATCH(DMI_BIOS_VERSION,
104 {set_max_cstate, "Medion 41700", {
105 DMI_MATCH(DMI_BIOS_VENDOR,
106 "Phoenix Technologies LTD"),
107 DMI_MATCH(DMI_BIOS_VERSION,
108 "R01-A1J")}, (void *)1},
109 {set_max_cstate, "Clevo 5600D", {
110 DMI_MATCH(DMI_BIOS_VENDOR,
111 "Phoenix Technologies LTD"),
112 DMI_MATCH(DMI_BIOS_VERSION,
113 "SHE845M0.86C.0013.D.0302131307")},
118 static inline u32 ticks_elapsed(u32 t1, u32 t2)
122 else if (!acpi_fadt.tmr_val_ext)
123 return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
125 return ((0xFFFFFFFF - t1) + t2);
129 acpi_processor_power_activate(struct acpi_processor *pr,
130 struct acpi_processor_cx *new)
132 struct acpi_processor_cx *old;
137 old = pr->power.state;
140 old->promotion.count = 0;
141 new->demotion.count = 0;
143 /* Cleanup from old state. */
147 /* Disable bus master reload */
148 if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
149 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0,
150 ACPI_MTX_DO_NOT_LOCK);
155 /* Prepare to use new state. */
158 /* Enable bus master reload */
159 if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
160 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1,
161 ACPI_MTX_DO_NOT_LOCK);
165 pr->power.state = new;
170 static void acpi_safe_halt(void)
172 int polling = test_thread_flag(TIF_POLLING_NRFLAG);
174 clear_thread_flag(TIF_POLLING_NRFLAG);
175 smp_mb__after_clear_bit();
180 set_thread_flag(TIF_POLLING_NRFLAG);
183 static atomic_t c3_cpu_count;
185 static void acpi_processor_idle(void)
187 struct acpi_processor *pr = NULL;
188 struct acpi_processor_cx *cx = NULL;
189 struct acpi_processor_cx *next_state = NULL;
193 pr = processors[smp_processor_id()];
198 * Interrupts must be disabled during bus mastering calculations and
199 * for C2/C3 transitions.
204 * Check whether we truly need to go idle, or should
207 if (unlikely(need_resched())) {
212 cx = pr->power.state;
224 * Check for bus mastering activity (if required), record, and check
227 if (pr->flags.bm_check) {
229 unsigned long diff = jiffies - pr->power.bm_check_timestamp;
235 /* if we didn't get called, assume there was busmaster activity */
238 pr->power.bm_activity |= 0x1;
239 pr->power.bm_activity <<= 1;
242 acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS,
243 &bm_status, ACPI_MTX_DO_NOT_LOCK);
245 pr->power.bm_activity++;
246 acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS,
247 1, ACPI_MTX_DO_NOT_LOCK);
250 * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
251 * the true state of bus mastering activity; forcing us to
252 * manually check the BMIDEA bit of each IDE channel.
254 else if (errata.piix4.bmisx) {
255 if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
256 || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
257 pr->power.bm_activity++;
260 pr->power.bm_check_timestamp = jiffies;
263 * Apply bus mastering demotion policy. Automatically demote
264 * to avoid a faulty transition. Note that the processor
265 * won't enter a low-power state during this call (to this
266 * funciton) but should upon the next.
268 * TBD: A better policy might be to fallback to the demotion
269 * state (use it for this quantum only) istead of
270 * demoting -- and rely on duration as our sole demotion
271 * qualification. This may, however, introduce DMA
272 * issues (e.g. floppy DMA transfer overrun/underrun).
274 if (pr->power.bm_activity & cx->demotion.threshold.bm) {
276 next_state = cx->demotion.state;
283 #ifdef CONFIG_HOTPLUG_CPU
285 * Check for P_LVL2_UP flag before entering C2 and above on
286 * an SMP system. We do it here instead of doing it at _CST/P_LVL
287 * detection phase, to work cleanly with logical CPU hotplug.
289 if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
290 !pr->flags.has_cst && acpi_fadt.plvl2_up)
291 cx->type = ACPI_STATE_C1;
296 * Invoke the current Cx state to put the processor to sleep.
303 * Use the appropriate idle routine, the one that would
304 * be used without acpi C-states.
312 * TBD: Can't get time duration while in C1, as resumes
313 * go to an ISR rather than here. Need to instrument
314 * base interrupt handler.
316 sleep_ticks = 0xFFFFFFFF;
320 /* Get start time (ticks) */
321 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
324 /* Dummy op - must do something useless after P_LVL2 read */
325 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
326 /* Get end time (ticks) */
327 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
328 /* Re-enable interrupts */
330 /* Compute time (ticks) that we were actually asleep */
332 ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
337 if (pr->flags.bm_check) {
338 if (atomic_inc_return(&c3_cpu_count) ==
341 * All CPUs are trying to go to C3
342 * Disable bus master arbitration
344 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1,
345 ACPI_MTX_DO_NOT_LOCK);
348 /* SMP with no shared cache... Invalidate cache */
349 ACPI_FLUSH_CPU_CACHE();
352 /* Get start time (ticks) */
353 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
356 /* Dummy op - must do something useless after P_LVL3 read */
357 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
358 /* Get end time (ticks) */
359 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
360 if (pr->flags.bm_check) {
361 /* Enable bus master arbitration */
362 atomic_dec(&c3_cpu_count);
363 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0,
364 ACPI_MTX_DO_NOT_LOCK);
367 /* Re-enable interrupts */
369 /* Compute time (ticks) that we were actually asleep */
371 ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;
379 next_state = pr->power.state;
384 * Track the number of longs (time asleep is greater than threshold)
385 * and promote when the count threshold is reached. Note that bus
386 * mastering activity may prevent promotions.
387 * Do not promote above max_cstate.
389 if (cx->promotion.state &&
390 ((cx->promotion.state - pr->power.states) <= max_cstate)) {
391 if (sleep_ticks > cx->promotion.threshold.ticks) {
392 cx->promotion.count++;
393 cx->demotion.count = 0;
394 if (cx->promotion.count >=
395 cx->promotion.threshold.count) {
396 if (pr->flags.bm_check) {
398 (pr->power.bm_activity & cx->
399 promotion.threshold.bm)) {
405 next_state = cx->promotion.state;
415 * Track the number of shorts (time asleep is less than time threshold)
416 * and demote when the usage threshold is reached.
418 if (cx->demotion.state) {
419 if (sleep_ticks < cx->demotion.threshold.ticks) {
420 cx->demotion.count++;
421 cx->promotion.count = 0;
422 if (cx->demotion.count >= cx->demotion.threshold.count) {
423 next_state = cx->demotion.state;
431 * Demote if current state exceeds max_cstate
433 if ((pr->power.state - pr->power.states) > max_cstate) {
434 if (cx->demotion.state)
435 next_state = cx->demotion.state;
441 * If we're going to start using a new Cx state we must clean up
442 * from the previous and prepare to use the new.
444 if (next_state != pr->power.state)
445 acpi_processor_power_activate(pr, next_state);
448 static int acpi_processor_set_power_policy(struct acpi_processor *pr)
451 unsigned int state_is_set = 0;
452 struct acpi_processor_cx *lower = NULL;
453 struct acpi_processor_cx *higher = NULL;
454 struct acpi_processor_cx *cx;
456 ACPI_FUNCTION_TRACE("acpi_processor_set_power_policy");
459 return_VALUE(-EINVAL);
462 * This function sets the default Cx state policy (OS idle handler).
463 * Our scheme is to promote quickly to C2 but more conservatively
464 * to C3. We're favoring C2 for its characteristics of low latency
465 * (quick response), good power savings, and ability to allow bus
466 * mastering activity. Note that the Cx state policy is completely
467 * customizable and can be altered dynamically.
471 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
472 cx = &pr->power.states[i];
477 pr->power.state = cx;
483 return_VALUE(-ENODEV);
486 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
487 cx = &pr->power.states[i];
492 cx->demotion.state = lower;
493 cx->demotion.threshold.ticks = cx->latency_ticks;
494 cx->demotion.threshold.count = 1;
495 if (cx->type == ACPI_STATE_C3)
496 cx->demotion.threshold.bm = bm_history;
503 for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
504 cx = &pr->power.states[i];
509 cx->promotion.state = higher;
510 cx->promotion.threshold.ticks = cx->latency_ticks;
511 if (cx->type >= ACPI_STATE_C2)
512 cx->promotion.threshold.count = 4;
514 cx->promotion.threshold.count = 10;
515 if (higher->type == ACPI_STATE_C3)
516 cx->promotion.threshold.bm = bm_history;
525 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
527 ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_fadt");
530 return_VALUE(-EINVAL);
533 return_VALUE(-ENODEV);
535 /* if info is obtained from pblk/fadt, type equals state */
536 pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
537 pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
539 #ifndef CONFIG_HOTPLUG_CPU
541 * Check for P_LVL2_UP flag before entering C2 and above on
544 if ((num_online_cpus() > 1) && acpi_fadt.plvl2_up)
545 return_VALUE(-ENODEV);
548 /* determine C2 and C3 address from pblk */
549 pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
550 pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
552 /* determine latencies from FADT */
553 pr->power.states[ACPI_STATE_C2].latency = acpi_fadt.plvl2_lat;
554 pr->power.states[ACPI_STATE_C3].latency = acpi_fadt.plvl3_lat;
556 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
557 "lvl2[0x%08x] lvl3[0x%08x]\n",
558 pr->power.states[ACPI_STATE_C2].address,
559 pr->power.states[ACPI_STATE_C3].address));
564 static int acpi_processor_get_power_info_default_c1(struct acpi_processor *pr)
566 ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_default_c1");
568 /* Zero initialize all the C-states info. */
569 memset(pr->power.states, 0, sizeof(pr->power.states));
571 /* set the first C-State to C1 */
572 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
574 /* the C0 state only exists as a filler in our array,
575 * and all processors need to support C1 */
576 pr->power.states[ACPI_STATE_C0].valid = 1;
577 pr->power.states[ACPI_STATE_C1].valid = 1;
582 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
584 acpi_status status = 0;
588 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
589 union acpi_object *cst;
591 ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_cst");
594 return_VALUE(-ENODEV);
598 /* Zero initialize C2 onwards and prepare for fresh CST lookup */
599 for (i = 2; i < ACPI_PROCESSOR_MAX_POWER; i++)
600 memset(&(pr->power.states[i]), 0,
601 sizeof(struct acpi_processor_cx));
603 status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
604 if (ACPI_FAILURE(status)) {
605 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
606 return_VALUE(-ENODEV);
609 cst = (union acpi_object *)buffer.pointer;
611 /* There must be at least 2 elements */
612 if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
613 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
614 "not enough elements in _CST\n"));
619 count = cst->package.elements[0].integer.value;
621 /* Validate number of power states. */
622 if (count < 1 || count != cst->package.count - 1) {
623 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
624 "count given by _CST is not valid\n"));
629 /* Tell driver that at least _CST is supported. */
630 pr->flags.has_cst = 1;
632 for (i = 1; i <= count; i++) {
633 union acpi_object *element;
634 union acpi_object *obj;
635 struct acpi_power_register *reg;
636 struct acpi_processor_cx cx;
638 memset(&cx, 0, sizeof(cx));
640 element = (union acpi_object *)&(cst->package.elements[i]);
641 if (element->type != ACPI_TYPE_PACKAGE)
644 if (element->package.count != 4)
647 obj = (union acpi_object *)&(element->package.elements[0]);
649 if (obj->type != ACPI_TYPE_BUFFER)
652 reg = (struct acpi_power_register *)obj->buffer.pointer;
654 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
655 (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
658 cx.address = (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) ?
661 /* There should be an easy way to extract an integer... */
662 obj = (union acpi_object *)&(element->package.elements[1]);
663 if (obj->type != ACPI_TYPE_INTEGER)
666 cx.type = obj->integer.value;
668 if ((cx.type != ACPI_STATE_C1) &&
669 (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO))
672 if ((cx.type < ACPI_STATE_C2) || (cx.type > ACPI_STATE_C3))
675 obj = (union acpi_object *)&(element->package.elements[2]);
676 if (obj->type != ACPI_TYPE_INTEGER)
679 cx.latency = obj->integer.value;
681 obj = (union acpi_object *)&(element->package.elements[3]);
682 if (obj->type != ACPI_TYPE_INTEGER)
685 cx.power = obj->integer.value;
688 memcpy(&(pr->power.states[current_count]), &cx, sizeof(cx));
691 * We support total ACPI_PROCESSOR_MAX_POWER - 1
692 * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1)
694 if (current_count >= (ACPI_PROCESSOR_MAX_POWER - 1)) {
696 "Limiting number of power states to max (%d)\n",
697 ACPI_PROCESSOR_MAX_POWER);
699 "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
704 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
707 /* Validate number of power states discovered */
708 if (current_count < 2)
712 acpi_os_free(buffer.pointer);
714 return_VALUE(status);
717 static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
719 ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c2");
725 * C2 latency must be less than or equal to 100
728 else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
729 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
730 "latency too large [%d]\n", cx->latency));
735 * Otherwise we've met all of our C2 requirements.
736 * Normalize the C2 latency to expidite policy
739 cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
744 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
745 struct acpi_processor_cx *cx)
747 static int bm_check_flag;
749 ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c3");
755 * C3 latency must be less than or equal to 1000
758 else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
759 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
760 "latency too large [%d]\n", cx->latency));
765 * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
766 * DMA transfers are used by any ISA device to avoid livelock.
767 * Note that we could disable Type-F DMA (as recommended by
768 * the erratum), but this is known to disrupt certain ISA
769 * devices thus we take the conservative approach.
771 else if (errata.piix4.fdma) {
772 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
773 "C3 not supported on PIIX4 with Type-F DMA\n"));
777 /* All the logic here assumes flags.bm_check is same across all CPUs */
778 if (!bm_check_flag) {
779 /* Determine whether bm_check is needed based on CPU */
780 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
781 bm_check_flag = pr->flags.bm_check;
783 pr->flags.bm_check = bm_check_flag;
786 if (pr->flags.bm_check) {
787 /* bus mastering control is necessary */
788 if (!pr->flags.bm_control) {
789 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
790 "C3 support requires bus mastering control\n"));
795 * WBINVD should be set in fadt, for C3 state to be
796 * supported on when bm_check is not required.
798 if (acpi_fadt.wb_invd != 1) {
799 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
800 "Cache invalidation should work properly"
801 " for C3 to be enabled on SMP systems\n"));
804 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD,
805 0, ACPI_MTX_DO_NOT_LOCK);
809 * Otherwise we've met all of our C3 requirements.
810 * Normalize the C3 latency to expidite policy. Enable
811 * checking of bus mastering status (bm_check) so we can
812 * use this in our C3 policy
815 cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
820 static int acpi_processor_power_verify(struct acpi_processor *pr)
823 unsigned int working = 0;
825 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
826 struct acpi_processor_cx *cx = &pr->power.states[i];
834 acpi_processor_power_verify_c2(cx);
838 acpi_processor_power_verify_c3(pr, cx);
849 static int acpi_processor_get_power_info(struct acpi_processor *pr)
854 ACPI_FUNCTION_TRACE("acpi_processor_get_power_info");
856 /* NOTE: the idle thread may not be running while calling
859 /* Adding C1 state */
860 acpi_processor_get_power_info_default_c1(pr);
861 result = acpi_processor_get_power_info_cst(pr);
862 if (result == -ENODEV)
863 acpi_processor_get_power_info_fadt(pr);
865 pr->power.count = acpi_processor_power_verify(pr);
870 * Now that we know which states are supported, set the default
871 * policy. Note that this policy can be changed dynamically
872 * (e.g. encourage deeper sleeps to conserve battery life when
875 result = acpi_processor_set_power_policy(pr);
877 return_VALUE(result);
880 * if one state of type C2 or C3 is available, mark this
881 * CPU as being "idle manageable"
883 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
884 if (pr->power.states[i].valid) {
886 if (pr->power.states[i].type >= ACPI_STATE_C2)
894 int acpi_processor_cst_has_changed(struct acpi_processor *pr)
898 ACPI_FUNCTION_TRACE("acpi_processor_cst_has_changed");
901 return_VALUE(-EINVAL);
904 return_VALUE(-ENODEV);
907 if (!pr->flags.power_setup_done)
908 return_VALUE(-ENODEV);
910 /* Fall back to the default idle loop */
911 pm_idle = pm_idle_save;
912 synchronize_sched(); /* Relies on interrupts forcing exit from idle. */
915 result = acpi_processor_get_power_info(pr);
916 if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
917 pm_idle = acpi_processor_idle;
919 return_VALUE(result);
924 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
926 struct acpi_processor *pr = (struct acpi_processor *)seq->private;
929 ACPI_FUNCTION_TRACE("acpi_processor_power_seq_show");
934 seq_printf(seq, "active state: C%zd\n"
936 "bus master activity: %08x\n",
937 pr->power.state ? pr->power.state - pr->power.states : 0,
938 max_cstate, (unsigned)pr->power.bm_activity);
940 seq_puts(seq, "states:\n");
942 for (i = 1; i <= pr->power.count; i++) {
943 seq_printf(seq, " %cC%d: ",
944 (&pr->power.states[i] ==
945 pr->power.state ? '*' : ' '), i);
947 if (!pr->power.states[i].valid) {
948 seq_puts(seq, "<not supported>\n");
952 switch (pr->power.states[i].type) {
954 seq_printf(seq, "type[C1] ");
957 seq_printf(seq, "type[C2] ");
960 seq_printf(seq, "type[C3] ");
963 seq_printf(seq, "type[--] ");
967 if (pr->power.states[i].promotion.state)
968 seq_printf(seq, "promotion[C%zd] ",
969 (pr->power.states[i].promotion.state -
972 seq_puts(seq, "promotion[--] ");
974 if (pr->power.states[i].demotion.state)
975 seq_printf(seq, "demotion[C%zd] ",
976 (pr->power.states[i].demotion.state -
979 seq_puts(seq, "demotion[--] ");
981 seq_printf(seq, "latency[%03d] usage[%08d]\n",
982 pr->power.states[i].latency,
983 pr->power.states[i].usage);
990 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file)
992 return single_open(file, acpi_processor_power_seq_show,
996 static struct file_operations acpi_processor_power_fops = {
997 .open = acpi_processor_power_open_fs,
1000 .release = single_release,
1003 int acpi_processor_power_init(struct acpi_processor *pr,
1004 struct acpi_device *device)
1006 acpi_status status = 0;
1007 static int first_run = 0;
1008 struct proc_dir_entry *entry = NULL;
1011 ACPI_FUNCTION_TRACE("acpi_processor_power_init");
1014 dmi_check_system(processor_power_dmi_table);
1015 if (max_cstate < ACPI_C_STATES_MAX)
1017 "ACPI: processor limited to max C-state %d\n",
1023 return_VALUE(-EINVAL);
1025 if (acpi_fadt.cst_cnt && !nocst) {
1027 acpi_os_write_port(acpi_fadt.smi_cmd, acpi_fadt.cst_cnt, 8);
1028 if (ACPI_FAILURE(status)) {
1029 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
1030 "Notifying BIOS of _CST ability failed\n"));
1034 acpi_processor_power_init_pdc(&(pr->power), pr->id);
1035 acpi_processor_set_pdc(pr, pr->power.pdc);
1036 acpi_processor_get_power_info(pr);
1039 * Install the idle handler if processor power management is supported.
1040 * Note that we use previously set idle handler will be used on
1041 * platforms that only support C1.
1043 if ((pr->flags.power) && (!boot_option_idle_override)) {
1044 printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
1045 for (i = 1; i <= pr->power.count; i++)
1046 if (pr->power.states[i].valid)
1047 printk(" C%d[C%d]", i,
1048 pr->power.states[i].type);
1052 pm_idle_save = pm_idle;
1053 pm_idle = acpi_processor_idle;
1058 entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1059 S_IRUGO, acpi_device_dir(device));
1061 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
1062 "Unable to create '%s' fs entry\n",
1063 ACPI_PROCESSOR_FILE_POWER));
1065 entry->proc_fops = &acpi_processor_power_fops;
1066 entry->data = acpi_driver_data(device);
1067 entry->owner = THIS_MODULE;
1070 pr->flags.power_setup_done = 1;
1075 int acpi_processor_power_exit(struct acpi_processor *pr,
1076 struct acpi_device *device)
1078 ACPI_FUNCTION_TRACE("acpi_processor_power_exit");
1080 pr->flags.power_setup_done = 0;
1082 if (acpi_device_dir(device))
1083 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1084 acpi_device_dir(device));
1086 /* Unregister the idle handler when processor #0 is removed. */
1088 pm_idle = pm_idle_save;
1091 * We are about to unload the current idle thread pm callback
1092 * (pm_idle), Wait for all processors to update cached/local
1093 * copies of pm_idle before proceeding.