1 /* 2 * processor_idle - idle state submodule to the ACPI processor driver 3 * 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, 2005 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 11 * 12 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 13 * 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. 18 * 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. 23 * 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. 27 * 28 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 29 */ 30 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() */ 41 #include <linux/latency.h> 42 #include <linux/clockchips.h> 43 44 /* 45 * Include the apic definitions for x86 to have the APIC timer related defines 46 * available also for UP (on SMP it gets magically included via linux/smp.h). 47 * asm/acpi.h is not an option, as it would require more include magic. Also 48 * creating an empty asm-ia64/apic.h would just trade pest vs. cholera. 49 */ 50 #ifdef CONFIG_X86 51 #include <asm/apic.h> 52 #endif 53 54 #include <asm/io.h> 55 #include <asm/uaccess.h> 56 57 #include <acpi/acpi_bus.h> 58 #include <acpi/processor.h> 59 60 #define ACPI_PROCESSOR_COMPONENT 0x01000000 61 #define ACPI_PROCESSOR_CLASS "processor" 62 #define _COMPONENT ACPI_PROCESSOR_COMPONENT 63 ACPI_MODULE_NAME("processor_idle"); 64 #define ACPI_PROCESSOR_FILE_POWER "power" 65 #define US_TO_PM_TIMER_TICKS(t) ((t * (PM_TIMER_FREQUENCY/1000)) / 1000) 66 #define PM_TIMER_TICK_NS (1000000000ULL/PM_TIMER_FREQUENCY) 67 #define C2_OVERHEAD 4 /* 1us (3.579 ticks per us) */ 68 #define C3_OVERHEAD 4 /* 1us (3.579 ticks per us) */ 69 static void (*pm_idle_save) (void) __read_mostly; 70 module_param(max_cstate, uint, 0644); 71 72 static unsigned int nocst __read_mostly; 73 module_param(nocst, uint, 0000); 74 75 /* 76 * bm_history -- bit-mask with a bit per jiffy of bus-master activity 77 * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms 78 * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms 79 * 100 HZ: 0x0000000F: 4 jiffies = 40ms 80 * reduce history for more aggressive entry into C3 81 */ 82 static unsigned int bm_history __read_mostly = 83 (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1)); 84 module_param(bm_history, uint, 0644); 85 /* -------------------------------------------------------------------------- 86 Power Management 87 -------------------------------------------------------------------------- */ 88 89 /* 90 * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3. 91 * For now disable this. Probably a bug somewhere else. 92 * 93 * To skip this limit, boot/load with a large max_cstate limit. 94 */ 95 static int set_max_cstate(const struct dmi_system_id *id) 96 { 97 if (max_cstate > ACPI_PROCESSOR_MAX_POWER) 98 return 0; 99 100 printk(KERN_NOTICE PREFIX "%s detected - limiting to C%ld max_cstate." 101 " Override with \"processor.max_cstate=%d\"\n", id->ident, 102 (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1); 103 104 max_cstate = (long)id->driver_data; 105 106 return 0; 107 } 108 109 /* Actually this shouldn't be __cpuinitdata, would be better to fix the 110 callers to only run once -AK */ 111 static struct dmi_system_id __cpuinitdata processor_power_dmi_table[] = { 112 { set_max_cstate, "IBM ThinkPad R40e", { 113 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), 114 DMI_MATCH(DMI_BIOS_VERSION,"1SET70WW")}, (void *)1}, 115 { set_max_cstate, "IBM ThinkPad R40e", { 116 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), 117 DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW")}, (void *)1}, 118 { set_max_cstate, "IBM ThinkPad R40e", { 119 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), 120 DMI_MATCH(DMI_BIOS_VERSION,"1SET43WW") }, (void*)1}, 121 { set_max_cstate, "IBM ThinkPad R40e", { 122 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), 123 DMI_MATCH(DMI_BIOS_VERSION,"1SET45WW") }, (void*)1}, 124 { set_max_cstate, "IBM ThinkPad R40e", { 125 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), 126 DMI_MATCH(DMI_BIOS_VERSION,"1SET47WW") }, (void*)1}, 127 { set_max_cstate, "IBM ThinkPad R40e", { 128 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), 129 DMI_MATCH(DMI_BIOS_VERSION,"1SET50WW") }, (void*)1}, 130 { set_max_cstate, "IBM ThinkPad R40e", { 131 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), 132 DMI_MATCH(DMI_BIOS_VERSION,"1SET52WW") }, (void*)1}, 133 { set_max_cstate, "IBM ThinkPad R40e", { 134 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), 135 DMI_MATCH(DMI_BIOS_VERSION,"1SET55WW") }, (void*)1}, 136 { set_max_cstate, "IBM ThinkPad R40e", { 137 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), 138 DMI_MATCH(DMI_BIOS_VERSION,"1SET56WW") }, (void*)1}, 139 { set_max_cstate, "IBM ThinkPad R40e", { 140 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), 141 DMI_MATCH(DMI_BIOS_VERSION,"1SET59WW") }, (void*)1}, 142 { set_max_cstate, "IBM ThinkPad R40e", { 143 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), 144 DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW") }, (void*)1}, 145 { set_max_cstate, "IBM ThinkPad R40e", { 146 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), 147 DMI_MATCH(DMI_BIOS_VERSION,"1SET61WW") }, (void*)1}, 148 { set_max_cstate, "IBM ThinkPad R40e", { 149 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), 150 DMI_MATCH(DMI_BIOS_VERSION,"1SET62WW") }, (void*)1}, 151 { set_max_cstate, "IBM ThinkPad R40e", { 152 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), 153 DMI_MATCH(DMI_BIOS_VERSION,"1SET64WW") }, (void*)1}, 154 { set_max_cstate, "IBM ThinkPad R40e", { 155 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), 156 DMI_MATCH(DMI_BIOS_VERSION,"1SET65WW") }, (void*)1}, 157 { set_max_cstate, "IBM ThinkPad R40e", { 158 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), 159 DMI_MATCH(DMI_BIOS_VERSION,"1SET68WW") }, (void*)1}, 160 { set_max_cstate, "Medion 41700", { 161 DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"), 162 DMI_MATCH(DMI_BIOS_VERSION,"R01-A1J")}, (void *)1}, 163 { set_max_cstate, "Clevo 5600D", { 164 DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"), 165 DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")}, 166 (void *)2}, 167 {}, 168 }; 169 170 static inline u32 ticks_elapsed(u32 t1, u32 t2) 171 { 172 if (t2 >= t1) 173 return (t2 - t1); 174 else if (!(acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER)) 175 return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF); 176 else 177 return ((0xFFFFFFFF - t1) + t2); 178 } 179 180 static void 181 acpi_processor_power_activate(struct acpi_processor *pr, 182 struct acpi_processor_cx *new) 183 { 184 struct acpi_processor_cx *old; 185 186 if (!pr || !new) 187 return; 188 189 old = pr->power.state; 190 191 if (old) 192 old->promotion.count = 0; 193 new->demotion.count = 0; 194 195 /* Cleanup from old state. */ 196 if (old) { 197 switch (old->type) { 198 case ACPI_STATE_C3: 199 /* Disable bus master reload */ 200 if (new->type != ACPI_STATE_C3 && pr->flags.bm_check) 201 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0); 202 break; 203 } 204 } 205 206 /* Prepare to use new state. */ 207 switch (new->type) { 208 case ACPI_STATE_C3: 209 /* Enable bus master reload */ 210 if (old->type != ACPI_STATE_C3 && pr->flags.bm_check) 211 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1); 212 break; 213 } 214 215 pr->power.state = new; 216 217 return; 218 } 219 220 static void acpi_safe_halt(void) 221 { 222 current_thread_info()->status &= ~TS_POLLING; 223 /* 224 * TS_POLLING-cleared state must be visible before we 225 * test NEED_RESCHED: 226 */ 227 smp_mb(); 228 if (!need_resched()) 229 safe_halt(); 230 current_thread_info()->status |= TS_POLLING; 231 } 232 233 static atomic_t c3_cpu_count; 234 235 /* Common C-state entry for C2, C3, .. */ 236 static void acpi_cstate_enter(struct acpi_processor_cx *cstate) 237 { 238 if (cstate->space_id == ACPI_CSTATE_FFH) { 239 /* Call into architectural FFH based C-state */ 240 acpi_processor_ffh_cstate_enter(cstate); 241 } else { 242 int unused; 243 /* IO port based C-state */ 244 inb(cstate->address); 245 /* Dummy wait op - must do something useless after P_LVL2 read 246 because chipsets cannot guarantee that STPCLK# signal 247 gets asserted in time to freeze execution properly. */ 248 unused = inl(acpi_gbl_FADT.xpm_timer_block.address); 249 } 250 } 251 252 #ifdef ARCH_APICTIMER_STOPS_ON_C3 253 254 /* 255 * Some BIOS implementations switch to C3 in the published C2 state. 256 * This seems to be a common problem on AMD boxen, but other vendors 257 * are affected too. We pick the most conservative approach: we assume 258 * that the local APIC stops in both C2 and C3. 259 */ 260 static void acpi_timer_check_state(int state, struct acpi_processor *pr, 261 struct acpi_processor_cx *cx) 262 { 263 struct acpi_processor_power *pwr = &pr->power; 264 u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2; 265 266 /* 267 * Check, if one of the previous states already marked the lapic 268 * unstable 269 */ 270 if (pwr->timer_broadcast_on_state < state) 271 return; 272 273 if (cx->type >= type) 274 pr->power.timer_broadcast_on_state = state; 275 } 276 277 static void acpi_propagate_timer_broadcast(struct acpi_processor *pr) 278 { 279 unsigned long reason; 280 281 reason = pr->power.timer_broadcast_on_state < INT_MAX ? 282 CLOCK_EVT_NOTIFY_BROADCAST_ON : CLOCK_EVT_NOTIFY_BROADCAST_OFF; 283 284 clockevents_notify(reason, &pr->id); 285 } 286 287 /* Power(C) State timer broadcast control */ 288 static void acpi_state_timer_broadcast(struct acpi_processor *pr, 289 struct acpi_processor_cx *cx, 290 int broadcast) 291 { 292 int state = cx - pr->power.states; 293 294 if (state >= pr->power.timer_broadcast_on_state) { 295 unsigned long reason; 296 297 reason = broadcast ? CLOCK_EVT_NOTIFY_BROADCAST_ENTER : 298 CLOCK_EVT_NOTIFY_BROADCAST_EXIT; 299 clockevents_notify(reason, &pr->id); 300 } 301 } 302 303 #else 304 305 static void acpi_timer_check_state(int state, struct acpi_processor *pr, 306 struct acpi_processor_cx *cstate) { } 307 static void acpi_propagate_timer_broadcast(struct acpi_processor *pr) { } 308 static void acpi_state_timer_broadcast(struct acpi_processor *pr, 309 struct acpi_processor_cx *cx, 310 int broadcast) 311 { 312 } 313 314 #endif 315 316 /* 317 * Suspend / resume control 318 */ 319 static int acpi_idle_suspend; 320 321 int acpi_processor_suspend(struct acpi_device * device, pm_message_t state) 322 { 323 acpi_idle_suspend = 1; 324 return 0; 325 } 326 327 int acpi_processor_resume(struct acpi_device * device) 328 { 329 acpi_idle_suspend = 0; 330 return 0; 331 } 332 333 static void acpi_processor_idle(void) 334 { 335 struct acpi_processor *pr = NULL; 336 struct acpi_processor_cx *cx = NULL; 337 struct acpi_processor_cx *next_state = NULL; 338 int sleep_ticks = 0; 339 u32 t1, t2 = 0; 340 341 /* 342 * Interrupts must be disabled during bus mastering calculations and 343 * for C2/C3 transitions. 344 */ 345 local_irq_disable(); 346 347 pr = processors[smp_processor_id()]; 348 if (!pr) { 349 local_irq_enable(); 350 return; 351 } 352 353 /* 354 * Check whether we truly need to go idle, or should 355 * reschedule: 356 */ 357 if (unlikely(need_resched())) { 358 local_irq_enable(); 359 return; 360 } 361 362 cx = pr->power.state; 363 if (!cx || acpi_idle_suspend) { 364 if (pm_idle_save) 365 pm_idle_save(); 366 else 367 acpi_safe_halt(); 368 return; 369 } 370 371 /* 372 * Check BM Activity 373 * ----------------- 374 * Check for bus mastering activity (if required), record, and check 375 * for demotion. 376 */ 377 if (pr->flags.bm_check) { 378 u32 bm_status = 0; 379 unsigned long diff = jiffies - pr->power.bm_check_timestamp; 380 381 if (diff > 31) 382 diff = 31; 383 384 pr->power.bm_activity <<= diff; 385 386 acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status); 387 if (bm_status) { 388 pr->power.bm_activity |= 0x1; 389 acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1); 390 } 391 /* 392 * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect 393 * the true state of bus mastering activity; forcing us to 394 * manually check the BMIDEA bit of each IDE channel. 395 */ 396 else if (errata.piix4.bmisx) { 397 if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01) 398 || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01)) 399 pr->power.bm_activity |= 0x1; 400 } 401 402 pr->power.bm_check_timestamp = jiffies; 403 404 /* 405 * If bus mastering is or was active this jiffy, demote 406 * to avoid a faulty transition. Note that the processor 407 * won't enter a low-power state during this call (to this 408 * function) but should upon the next. 409 * 410 * TBD: A better policy might be to fallback to the demotion 411 * state (use it for this quantum only) istead of 412 * demoting -- and rely on duration as our sole demotion 413 * qualification. This may, however, introduce DMA 414 * issues (e.g. floppy DMA transfer overrun/underrun). 415 */ 416 if ((pr->power.bm_activity & 0x1) && 417 cx->demotion.threshold.bm) { 418 local_irq_enable(); 419 next_state = cx->demotion.state; 420 goto end; 421 } 422 } 423 424 #ifdef CONFIG_HOTPLUG_CPU 425 /* 426 * Check for P_LVL2_UP flag before entering C2 and above on 427 * an SMP system. We do it here instead of doing it at _CST/P_LVL 428 * detection phase, to work cleanly with logical CPU hotplug. 429 */ 430 if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) && 431 !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED)) 432 cx = &pr->power.states[ACPI_STATE_C1]; 433 #endif 434 435 /* 436 * Sleep: 437 * ------ 438 * Invoke the current Cx state to put the processor to sleep. 439 */ 440 if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) { 441 current_thread_info()->status &= ~TS_POLLING; 442 /* 443 * TS_POLLING-cleared state must be visible before we 444 * test NEED_RESCHED: 445 */ 446 smp_mb(); 447 if (need_resched()) { 448 current_thread_info()->status |= TS_POLLING; 449 local_irq_enable(); 450 return; 451 } 452 } 453 454 switch (cx->type) { 455 456 case ACPI_STATE_C1: 457 /* 458 * Invoke C1. 459 * Use the appropriate idle routine, the one that would 460 * be used without acpi C-states. 461 */ 462 if (pm_idle_save) 463 pm_idle_save(); 464 else 465 acpi_safe_halt(); 466 467 /* 468 * TBD: Can't get time duration while in C1, as resumes 469 * go to an ISR rather than here. Need to instrument 470 * base interrupt handler. 471 * 472 * Note: the TSC better not stop in C1, sched_clock() will 473 * skew otherwise. 474 */ 475 sleep_ticks = 0xFFFFFFFF; 476 break; 477 478 case ACPI_STATE_C2: 479 /* Get start time (ticks) */ 480 t1 = inl(acpi_gbl_FADT.xpm_timer_block.address); 481 /* Tell the scheduler that we are going deep-idle: */ 482 sched_clock_idle_sleep_event(); 483 /* Invoke C2 */ 484 acpi_state_timer_broadcast(pr, cx, 1); 485 acpi_cstate_enter(cx); 486 /* Get end time (ticks) */ 487 t2 = inl(acpi_gbl_FADT.xpm_timer_block.address); 488 489 #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC) 490 /* TSC halts in C2, so notify users */ 491 mark_tsc_unstable("possible TSC halt in C2"); 492 #endif 493 /* Compute time (ticks) that we were actually asleep */ 494 sleep_ticks = ticks_elapsed(t1, t2); 495 496 /* Tell the scheduler how much we idled: */ 497 sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS); 498 499 /* Re-enable interrupts */ 500 local_irq_enable(); 501 /* Do not account our idle-switching overhead: */ 502 sleep_ticks -= cx->latency_ticks + C2_OVERHEAD; 503 504 current_thread_info()->status |= TS_POLLING; 505 acpi_state_timer_broadcast(pr, cx, 0); 506 break; 507 508 case ACPI_STATE_C3: 509 /* 510 * disable bus master 511 * bm_check implies we need ARB_DIS 512 * !bm_check implies we need cache flush 513 * bm_control implies whether we can do ARB_DIS 514 * 515 * That leaves a case where bm_check is set and bm_control is 516 * not set. In that case we cannot do much, we enter C3 517 * without doing anything. 518 */ 519 if (pr->flags.bm_check && pr->flags.bm_control) { 520 if (atomic_inc_return(&c3_cpu_count) == 521 num_online_cpus()) { 522 /* 523 * All CPUs are trying to go to C3 524 * Disable bus master arbitration 525 */ 526 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1); 527 } 528 } else if (!pr->flags.bm_check) { 529 /* SMP with no shared cache... Invalidate cache */ 530 ACPI_FLUSH_CPU_CACHE(); 531 } 532 533 /* Get start time (ticks) */ 534 t1 = inl(acpi_gbl_FADT.xpm_timer_block.address); 535 /* Invoke C3 */ 536 acpi_state_timer_broadcast(pr, cx, 1); 537 /* Tell the scheduler that we are going deep-idle: */ 538 sched_clock_idle_sleep_event(); 539 acpi_cstate_enter(cx); 540 /* Get end time (ticks) */ 541 t2 = inl(acpi_gbl_FADT.xpm_timer_block.address); 542 if (pr->flags.bm_check && pr->flags.bm_control) { 543 /* Enable bus master arbitration */ 544 atomic_dec(&c3_cpu_count); 545 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0); 546 } 547 548 #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC) 549 /* TSC halts in C3, so notify users */ 550 mark_tsc_unstable("TSC halts in C3"); 551 #endif 552 /* Compute time (ticks) that we were actually asleep */ 553 sleep_ticks = ticks_elapsed(t1, t2); 554 /* Tell the scheduler how much we idled: */ 555 sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS); 556 557 /* Re-enable interrupts */ 558 local_irq_enable(); 559 /* Do not account our idle-switching overhead: */ 560 sleep_ticks -= cx->latency_ticks + C3_OVERHEAD; 561 562 current_thread_info()->status |= TS_POLLING; 563 acpi_state_timer_broadcast(pr, cx, 0); 564 break; 565 566 default: 567 local_irq_enable(); 568 return; 569 } 570 cx->usage++; 571 if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0)) 572 cx->time += sleep_ticks; 573 574 next_state = pr->power.state; 575 576 #ifdef CONFIG_HOTPLUG_CPU 577 /* Don't do promotion/demotion */ 578 if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) && 579 !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED)) { 580 next_state = cx; 581 goto end; 582 } 583 #endif 584 585 /* 586 * Promotion? 587 * ---------- 588 * Track the number of longs (time asleep is greater than threshold) 589 * and promote when the count threshold is reached. Note that bus 590 * mastering activity may prevent promotions. 591 * Do not promote above max_cstate. 592 */ 593 if (cx->promotion.state && 594 ((cx->promotion.state - pr->power.states) <= max_cstate)) { 595 if (sleep_ticks > cx->promotion.threshold.ticks && 596 cx->promotion.state->latency <= system_latency_constraint()) { 597 cx->promotion.count++; 598 cx->demotion.count = 0; 599 if (cx->promotion.count >= 600 cx->promotion.threshold.count) { 601 if (pr->flags.bm_check) { 602 if (! 603 (pr->power.bm_activity & cx-> 604 promotion.threshold.bm)) { 605 next_state = 606 cx->promotion.state; 607 goto end; 608 } 609 } else { 610 next_state = cx->promotion.state; 611 goto end; 612 } 613 } 614 } 615 } 616 617 /* 618 * Demotion? 619 * --------- 620 * Track the number of shorts (time asleep is less than time threshold) 621 * and demote when the usage threshold is reached. 622 */ 623 if (cx->demotion.state) { 624 if (sleep_ticks < cx->demotion.threshold.ticks) { 625 cx->demotion.count++; 626 cx->promotion.count = 0; 627 if (cx->demotion.count >= cx->demotion.threshold.count) { 628 next_state = cx->demotion.state; 629 goto end; 630 } 631 } 632 } 633 634 end: 635 /* 636 * Demote if current state exceeds max_cstate 637 * or if the latency of the current state is unacceptable 638 */ 639 if ((pr->power.state - pr->power.states) > max_cstate || 640 pr->power.state->latency > system_latency_constraint()) { 641 if (cx->demotion.state) 642 next_state = cx->demotion.state; 643 } 644 645 /* 646 * New Cx State? 647 * ------------- 648 * If we're going to start using a new Cx state we must clean up 649 * from the previous and prepare to use the new. 650 */ 651 if (next_state != pr->power.state) 652 acpi_processor_power_activate(pr, next_state); 653 } 654 655 static int acpi_processor_set_power_policy(struct acpi_processor *pr) 656 { 657 unsigned int i; 658 unsigned int state_is_set = 0; 659 struct acpi_processor_cx *lower = NULL; 660 struct acpi_processor_cx *higher = NULL; 661 struct acpi_processor_cx *cx; 662 663 664 if (!pr) 665 return -EINVAL; 666 667 /* 668 * This function sets the default Cx state policy (OS idle handler). 669 * Our scheme is to promote quickly to C2 but more conservatively 670 * to C3. We're favoring C2 for its characteristics of low latency 671 * (quick response), good power savings, and ability to allow bus 672 * mastering activity. Note that the Cx state policy is completely 673 * customizable and can be altered dynamically. 674 */ 675 676 /* startup state */ 677 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { 678 cx = &pr->power.states[i]; 679 if (!cx->valid) 680 continue; 681 682 if (!state_is_set) 683 pr->power.state = cx; 684 state_is_set++; 685 break; 686 } 687 688 if (!state_is_set) 689 return -ENODEV; 690 691 /* demotion */ 692 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { 693 cx = &pr->power.states[i]; 694 if (!cx->valid) 695 continue; 696 697 if (lower) { 698 cx->demotion.state = lower; 699 cx->demotion.threshold.ticks = cx->latency_ticks; 700 cx->demotion.threshold.count = 1; 701 if (cx->type == ACPI_STATE_C3) 702 cx->demotion.threshold.bm = bm_history; 703 } 704 705 lower = cx; 706 } 707 708 /* promotion */ 709 for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) { 710 cx = &pr->power.states[i]; 711 if (!cx->valid) 712 continue; 713 714 if (higher) { 715 cx->promotion.state = higher; 716 cx->promotion.threshold.ticks = cx->latency_ticks; 717 if (cx->type >= ACPI_STATE_C2) 718 cx->promotion.threshold.count = 4; 719 else 720 cx->promotion.threshold.count = 10; 721 if (higher->type == ACPI_STATE_C3) 722 cx->promotion.threshold.bm = bm_history; 723 } 724 725 higher = cx; 726 } 727 728 return 0; 729 } 730 731 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr) 732 { 733 734 if (!pr) 735 return -EINVAL; 736 737 if (!pr->pblk) 738 return -ENODEV; 739 740 /* if info is obtained from pblk/fadt, type equals state */ 741 pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2; 742 pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3; 743 744 #ifndef CONFIG_HOTPLUG_CPU 745 /* 746 * Check for P_LVL2_UP flag before entering C2 and above on 747 * an SMP system. 748 */ 749 if ((num_online_cpus() > 1) && 750 !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED)) 751 return -ENODEV; 752 #endif 753 754 /* determine C2 and C3 address from pblk */ 755 pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4; 756 pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5; 757 758 /* determine latencies from FADT */ 759 pr->power.states[ACPI_STATE_C2].latency = acpi_gbl_FADT.C2latency; 760 pr->power.states[ACPI_STATE_C3].latency = acpi_gbl_FADT.C3latency; 761 762 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 763 "lvl2[0x%08x] lvl3[0x%08x]\n", 764 pr->power.states[ACPI_STATE_C2].address, 765 pr->power.states[ACPI_STATE_C3].address)); 766 767 return 0; 768 } 769 770 static int acpi_processor_get_power_info_default(struct acpi_processor *pr) 771 { 772 if (!pr->power.states[ACPI_STATE_C1].valid) { 773 /* set the first C-State to C1 */ 774 /* all processors need to support C1 */ 775 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1; 776 pr->power.states[ACPI_STATE_C1].valid = 1; 777 } 778 /* the C0 state only exists as a filler in our array */ 779 pr->power.states[ACPI_STATE_C0].valid = 1; 780 return 0; 781 } 782 783 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr) 784 { 785 acpi_status status = 0; 786 acpi_integer count; 787 int current_count; 788 int i; 789 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; 790 union acpi_object *cst; 791 792 793 if (nocst) 794 return -ENODEV; 795 796 current_count = 0; 797 798 status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer); 799 if (ACPI_FAILURE(status)) { 800 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n")); 801 return -ENODEV; 802 } 803 804 cst = buffer.pointer; 805 806 /* There must be at least 2 elements */ 807 if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) { 808 printk(KERN_ERR PREFIX "not enough elements in _CST\n"); 809 status = -EFAULT; 810 goto end; 811 } 812 813 count = cst->package.elements[0].integer.value; 814 815 /* Validate number of power states. */ 816 if (count < 1 || count != cst->package.count - 1) { 817 printk(KERN_ERR PREFIX "count given by _CST is not valid\n"); 818 status = -EFAULT; 819 goto end; 820 } 821 822 /* Tell driver that at least _CST is supported. */ 823 pr->flags.has_cst = 1; 824 825 for (i = 1; i <= count; i++) { 826 union acpi_object *element; 827 union acpi_object *obj; 828 struct acpi_power_register *reg; 829 struct acpi_processor_cx cx; 830 831 memset(&cx, 0, sizeof(cx)); 832 833 element = &(cst->package.elements[i]); 834 if (element->type != ACPI_TYPE_PACKAGE) 835 continue; 836 837 if (element->package.count != 4) 838 continue; 839 840 obj = &(element->package.elements[0]); 841 842 if (obj->type != ACPI_TYPE_BUFFER) 843 continue; 844 845 reg = (struct acpi_power_register *)obj->buffer.pointer; 846 847 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO && 848 (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)) 849 continue; 850 851 /* There should be an easy way to extract an integer... */ 852 obj = &(element->package.elements[1]); 853 if (obj->type != ACPI_TYPE_INTEGER) 854 continue; 855 856 cx.type = obj->integer.value; 857 /* 858 * Some buggy BIOSes won't list C1 in _CST - 859 * Let acpi_processor_get_power_info_default() handle them later 860 */ 861 if (i == 1 && cx.type != ACPI_STATE_C1) 862 current_count++; 863 864 cx.address = reg->address; 865 cx.index = current_count + 1; 866 867 cx.space_id = ACPI_CSTATE_SYSTEMIO; 868 if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) { 869 if (acpi_processor_ffh_cstate_probe 870 (pr->id, &cx, reg) == 0) { 871 cx.space_id = ACPI_CSTATE_FFH; 872 } else if (cx.type != ACPI_STATE_C1) { 873 /* 874 * C1 is a special case where FIXED_HARDWARE 875 * can be handled in non-MWAIT way as well. 876 * In that case, save this _CST entry info. 877 * That is, we retain space_id of SYSTEM_IO for 878 * halt based C1. 879 * Otherwise, ignore this info and continue. 880 */ 881 continue; 882 } 883 } 884 885 obj = &(element->package.elements[2]); 886 if (obj->type != ACPI_TYPE_INTEGER) 887 continue; 888 889 cx.latency = obj->integer.value; 890 891 obj = &(element->package.elements[3]); 892 if (obj->type != ACPI_TYPE_INTEGER) 893 continue; 894 895 cx.power = obj->integer.value; 896 897 current_count++; 898 memcpy(&(pr->power.states[current_count]), &cx, sizeof(cx)); 899 900 /* 901 * We support total ACPI_PROCESSOR_MAX_POWER - 1 902 * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1) 903 */ 904 if (current_count >= (ACPI_PROCESSOR_MAX_POWER - 1)) { 905 printk(KERN_WARNING 906 "Limiting number of power states to max (%d)\n", 907 ACPI_PROCESSOR_MAX_POWER); 908 printk(KERN_WARNING 909 "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n"); 910 break; 911 } 912 } 913 914 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n", 915 current_count)); 916 917 /* Validate number of power states discovered */ 918 if (current_count < 2) 919 status = -EFAULT; 920 921 end: 922 kfree(buffer.pointer); 923 924 return status; 925 } 926 927 static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx) 928 { 929 930 if (!cx->address) 931 return; 932 933 /* 934 * C2 latency must be less than or equal to 100 935 * microseconds. 936 */ 937 else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) { 938 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 939 "latency too large [%d]\n", cx->latency)); 940 return; 941 } 942 943 /* 944 * Otherwise we've met all of our C2 requirements. 945 * Normalize the C2 latency to expidite policy 946 */ 947 cx->valid = 1; 948 cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency); 949 950 return; 951 } 952 953 static void acpi_processor_power_verify_c3(struct acpi_processor *pr, 954 struct acpi_processor_cx *cx) 955 { 956 static int bm_check_flag; 957 958 959 if (!cx->address) 960 return; 961 962 /* 963 * C3 latency must be less than or equal to 1000 964 * microseconds. 965 */ 966 else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) { 967 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 968 "latency too large [%d]\n", cx->latency)); 969 return; 970 } 971 972 /* 973 * PIIX4 Erratum #18: We don't support C3 when Type-F (fast) 974 * DMA transfers are used by any ISA device to avoid livelock. 975 * Note that we could disable Type-F DMA (as recommended by 976 * the erratum), but this is known to disrupt certain ISA 977 * devices thus we take the conservative approach. 978 */ 979 else if (errata.piix4.fdma) { 980 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 981 "C3 not supported on PIIX4 with Type-F DMA\n")); 982 return; 983 } 984 985 /* All the logic here assumes flags.bm_check is same across all CPUs */ 986 if (!bm_check_flag) { 987 /* Determine whether bm_check is needed based on CPU */ 988 acpi_processor_power_init_bm_check(&(pr->flags), pr->id); 989 bm_check_flag = pr->flags.bm_check; 990 } else { 991 pr->flags.bm_check = bm_check_flag; 992 } 993 994 if (pr->flags.bm_check) { 995 if (!pr->flags.bm_control) { 996 if (pr->flags.has_cst != 1) { 997 /* bus mastering control is necessary */ 998 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 999 "C3 support requires BM control\n")); 1000 return; 1001 } else { 1002 /* Here we enter C3 without bus mastering */ 1003 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 1004 "C3 support without BM control\n")); 1005 } 1006 } 1007 } else { 1008 /* 1009 * WBINVD should be set in fadt, for C3 state to be 1010 * supported on when bm_check is not required. 1011 */ 1012 if (!(acpi_gbl_FADT.flags & ACPI_FADT_WBINVD)) { 1013 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 1014 "Cache invalidation should work properly" 1015 " for C3 to be enabled on SMP systems\n")); 1016 return; 1017 } 1018 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0); 1019 } 1020 1021 /* 1022 * Otherwise we've met all of our C3 requirements. 1023 * Normalize the C3 latency to expidite policy. Enable 1024 * checking of bus mastering status (bm_check) so we can 1025 * use this in our C3 policy 1026 */ 1027 cx->valid = 1; 1028 cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency); 1029 1030 return; 1031 } 1032 1033 static int acpi_processor_power_verify(struct acpi_processor *pr) 1034 { 1035 unsigned int i; 1036 unsigned int working = 0; 1037 1038 pr->power.timer_broadcast_on_state = INT_MAX; 1039 1040 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { 1041 struct acpi_processor_cx *cx = &pr->power.states[i]; 1042 1043 switch (cx->type) { 1044 case ACPI_STATE_C1: 1045 cx->valid = 1; 1046 break; 1047 1048 case ACPI_STATE_C2: 1049 acpi_processor_power_verify_c2(cx); 1050 if (cx->valid) 1051 acpi_timer_check_state(i, pr, cx); 1052 break; 1053 1054 case ACPI_STATE_C3: 1055 acpi_processor_power_verify_c3(pr, cx); 1056 if (cx->valid) 1057 acpi_timer_check_state(i, pr, cx); 1058 break; 1059 } 1060 1061 if (cx->valid) 1062 working++; 1063 } 1064 1065 acpi_propagate_timer_broadcast(pr); 1066 1067 return (working); 1068 } 1069 1070 static int acpi_processor_get_power_info(struct acpi_processor *pr) 1071 { 1072 unsigned int i; 1073 int result; 1074 1075 1076 /* NOTE: the idle thread may not be running while calling 1077 * this function */ 1078 1079 /* Zero initialize all the C-states info. */ 1080 memset(pr->power.states, 0, sizeof(pr->power.states)); 1081 1082 result = acpi_processor_get_power_info_cst(pr); 1083 if (result == -ENODEV) 1084 result = acpi_processor_get_power_info_fadt(pr); 1085 1086 if (result) 1087 return result; 1088 1089 acpi_processor_get_power_info_default(pr); 1090 1091 pr->power.count = acpi_processor_power_verify(pr); 1092 1093 /* 1094 * Set Default Policy 1095 * ------------------ 1096 * Now that we know which states are supported, set the default 1097 * policy. Note that this policy can be changed dynamically 1098 * (e.g. encourage deeper sleeps to conserve battery life when 1099 * not on AC). 1100 */ 1101 result = acpi_processor_set_power_policy(pr); 1102 if (result) 1103 return result; 1104 1105 /* 1106 * if one state of type C2 or C3 is available, mark this 1107 * CPU as being "idle manageable" 1108 */ 1109 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { 1110 if (pr->power.states[i].valid) { 1111 pr->power.count = i; 1112 if (pr->power.states[i].type >= ACPI_STATE_C2) 1113 pr->flags.power = 1; 1114 } 1115 } 1116 1117 return 0; 1118 } 1119 1120 int acpi_processor_cst_has_changed(struct acpi_processor *pr) 1121 { 1122 int result = 0; 1123 1124 1125 if (!pr) 1126 return -EINVAL; 1127 1128 if (nocst) { 1129 return -ENODEV; 1130 } 1131 1132 if (!pr->flags.power_setup_done) 1133 return -ENODEV; 1134 1135 /* Fall back to the default idle loop */ 1136 pm_idle = pm_idle_save; 1137 synchronize_sched(); /* Relies on interrupts forcing exit from idle. */ 1138 1139 pr->flags.power = 0; 1140 result = acpi_processor_get_power_info(pr); 1141 if ((pr->flags.power == 1) && (pr->flags.power_setup_done)) 1142 pm_idle = acpi_processor_idle; 1143 1144 return result; 1145 } 1146 1147 /* proc interface */ 1148 1149 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset) 1150 { 1151 struct acpi_processor *pr = seq->private; 1152 unsigned int i; 1153 1154 1155 if (!pr) 1156 goto end; 1157 1158 seq_printf(seq, "active state: C%zd\n" 1159 "max_cstate: C%d\n" 1160 "bus master activity: %08x\n" 1161 "maximum allowed latency: %d usec\n", 1162 pr->power.state ? pr->power.state - pr->power.states : 0, 1163 max_cstate, (unsigned)pr->power.bm_activity, 1164 system_latency_constraint()); 1165 1166 seq_puts(seq, "states:\n"); 1167 1168 for (i = 1; i <= pr->power.count; i++) { 1169 seq_printf(seq, " %cC%d: ", 1170 (&pr->power.states[i] == 1171 pr->power.state ? '*' : ' '), i); 1172 1173 if (!pr->power.states[i].valid) { 1174 seq_puts(seq, "<not supported>\n"); 1175 continue; 1176 } 1177 1178 switch (pr->power.states[i].type) { 1179 case ACPI_STATE_C1: 1180 seq_printf(seq, "type[C1] "); 1181 break; 1182 case ACPI_STATE_C2: 1183 seq_printf(seq, "type[C2] "); 1184 break; 1185 case ACPI_STATE_C3: 1186 seq_printf(seq, "type[C3] "); 1187 break; 1188 default: 1189 seq_printf(seq, "type[--] "); 1190 break; 1191 } 1192 1193 if (pr->power.states[i].promotion.state) 1194 seq_printf(seq, "promotion[C%zd] ", 1195 (pr->power.states[i].promotion.state - 1196 pr->power.states)); 1197 else 1198 seq_puts(seq, "promotion[--] "); 1199 1200 if (pr->power.states[i].demotion.state) 1201 seq_printf(seq, "demotion[C%zd] ", 1202 (pr->power.states[i].demotion.state - 1203 pr->power.states)); 1204 else 1205 seq_puts(seq, "demotion[--] "); 1206 1207 seq_printf(seq, "latency[%03d] usage[%08d] duration[%020llu]\n", 1208 pr->power.states[i].latency, 1209 pr->power.states[i].usage, 1210 (unsigned long long)pr->power.states[i].time); 1211 } 1212 1213 end: 1214 return 0; 1215 } 1216 1217 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file) 1218 { 1219 return single_open(file, acpi_processor_power_seq_show, 1220 PDE(inode)->data); 1221 } 1222 1223 static const struct file_operations acpi_processor_power_fops = { 1224 .open = acpi_processor_power_open_fs, 1225 .read = seq_read, 1226 .llseek = seq_lseek, 1227 .release = single_release, 1228 }; 1229 1230 #ifdef CONFIG_SMP 1231 static void smp_callback(void *v) 1232 { 1233 /* we already woke the CPU up, nothing more to do */ 1234 } 1235 1236 /* 1237 * This function gets called when a part of the kernel has a new latency 1238 * requirement. This means we need to get all processors out of their C-state, 1239 * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that 1240 * wakes them all right up. 1241 */ 1242 static int acpi_processor_latency_notify(struct notifier_block *b, 1243 unsigned long l, void *v) 1244 { 1245 smp_call_function(smp_callback, NULL, 0, 1); 1246 return NOTIFY_OK; 1247 } 1248 1249 static struct notifier_block acpi_processor_latency_notifier = { 1250 .notifier_call = acpi_processor_latency_notify, 1251 }; 1252 #endif 1253 1254 int __cpuinit acpi_processor_power_init(struct acpi_processor *pr, 1255 struct acpi_device *device) 1256 { 1257 acpi_status status = 0; 1258 static int first_run; 1259 struct proc_dir_entry *entry = NULL; 1260 unsigned int i; 1261 1262 1263 if (!first_run) { 1264 dmi_check_system(processor_power_dmi_table); 1265 if (max_cstate < ACPI_C_STATES_MAX) 1266 printk(KERN_NOTICE 1267 "ACPI: processor limited to max C-state %d\n", 1268 max_cstate); 1269 first_run++; 1270 #ifdef CONFIG_SMP 1271 register_latency_notifier(&acpi_processor_latency_notifier); 1272 #endif 1273 } 1274 1275 if (!pr) 1276 return -EINVAL; 1277 1278 if (acpi_gbl_FADT.cst_control && !nocst) { 1279 status = 1280 acpi_os_write_port(acpi_gbl_FADT.smi_command, acpi_gbl_FADT.cst_control, 8); 1281 if (ACPI_FAILURE(status)) { 1282 ACPI_EXCEPTION((AE_INFO, status, 1283 "Notifying BIOS of _CST ability failed")); 1284 } 1285 } 1286 1287 acpi_processor_get_power_info(pr); 1288 1289 /* 1290 * Install the idle handler if processor power management is supported. 1291 * Note that we use previously set idle handler will be used on 1292 * platforms that only support C1. 1293 */ 1294 if ((pr->flags.power) && (!boot_option_idle_override)) { 1295 printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id); 1296 for (i = 1; i <= pr->power.count; i++) 1297 if (pr->power.states[i].valid) 1298 printk(" C%d[C%d]", i, 1299 pr->power.states[i].type); 1300 printk(")\n"); 1301 1302 if (pr->id == 0) { 1303 pm_idle_save = pm_idle; 1304 pm_idle = acpi_processor_idle; 1305 } 1306 } 1307 1308 /* 'power' [R] */ 1309 entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER, 1310 S_IRUGO, acpi_device_dir(device)); 1311 if (!entry) 1312 return -EIO; 1313 else { 1314 entry->proc_fops = &acpi_processor_power_fops; 1315 entry->data = acpi_driver_data(device); 1316 entry->owner = THIS_MODULE; 1317 } 1318 1319 pr->flags.power_setup_done = 1; 1320 1321 return 0; 1322 } 1323 1324 int acpi_processor_power_exit(struct acpi_processor *pr, 1325 struct acpi_device *device) 1326 { 1327 1328 pr->flags.power_setup_done = 0; 1329 1330 if (acpi_device_dir(device)) 1331 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER, 1332 acpi_device_dir(device)); 1333 1334 /* Unregister the idle handler when processor #0 is removed. */ 1335 if (pr->id == 0) { 1336 pm_idle = pm_idle_save; 1337 1338 /* 1339 * We are about to unload the current idle thread pm callback 1340 * (pm_idle), Wait for all processors to update cached/local 1341 * copies of pm_idle before proceeding. 1342 */ 1343 cpu_idle_wait(); 1344 #ifdef CONFIG_SMP 1345 unregister_latency_notifier(&acpi_processor_latency_notifier); 1346 #endif 1347 } 1348 1349 return 0; 1350 } 1351