git.oblomov.eu Git - linux-2.6/blob - drivers/acpi/processor_idle.c

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