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