Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6/linux-2.6-openrd.git] / drivers / acpi / processor_perflib.c
blob2cabadcc4d8c36806bc886080a6c0cae3d50dd04
1 /*
2 * processor_perflib.c - ACPI Processor P-States Library ($Revision: 71 $)
4 * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6 * Copyright (C) 2004 Dominik Brodowski <linux@brodo.de>
7 * Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
8 * - Added processor hotplug support
11 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or (at
16 * your option) any later version.
18 * This program is distributed in the hope that it will be useful, but
19 * WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
21 * General Public License for more details.
23 * You should have received a copy of the GNU General Public License along
24 * with this program; if not, write to the Free Software Foundation, Inc.,
25 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
29 #include <linux/kernel.h>
30 #include <linux/module.h>
31 #include <linux/init.h>
32 #include <linux/cpufreq.h>
34 #ifdef CONFIG_X86
35 #include <asm/cpufeature.h>
36 #endif
38 #include <acpi/acpi_bus.h>
39 #include <acpi/acpi_drivers.h>
40 #include <acpi/processor.h>
42 #define PREFIX "ACPI: "
44 #define ACPI_PROCESSOR_CLASS "processor"
45 #define ACPI_PROCESSOR_FILE_PERFORMANCE "performance"
46 #define _COMPONENT ACPI_PROCESSOR_COMPONENT
47 ACPI_MODULE_NAME("processor_perflib");
49 static DEFINE_MUTEX(performance_mutex);
51 /* Use cpufreq debug layer for _PPC changes. */
52 #define cpufreq_printk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, \
53 "cpufreq-core", msg)
56 * _PPC support is implemented as a CPUfreq policy notifier:
57 * This means each time a CPUfreq driver registered also with
58 * the ACPI core is asked to change the speed policy, the maximum
59 * value is adjusted so that it is within the platform limit.
61 * Also, when a new platform limit value is detected, the CPUfreq
62 * policy is adjusted accordingly.
65 /* ignore_ppc:
66 * -1 -> cpufreq low level drivers not initialized -> _PSS, etc. not called yet
67 * ignore _PPC
68 * 0 -> cpufreq low level drivers initialized -> consider _PPC values
69 * 1 -> ignore _PPC totally -> forced by user through boot param
71 static int ignore_ppc = -1;
72 module_param(ignore_ppc, int, 0644);
73 MODULE_PARM_DESC(ignore_ppc, "If the frequency of your machine gets wrongly" \
74 "limited by BIOS, this should help");
76 #define PPC_REGISTERED 1
77 #define PPC_IN_USE 2
79 static int acpi_processor_ppc_status;
81 static int acpi_processor_ppc_notifier(struct notifier_block *nb,
82 unsigned long event, void *data)
84 struct cpufreq_policy *policy = data;
85 struct acpi_processor *pr;
86 unsigned int ppc = 0;
88 if (event == CPUFREQ_START && ignore_ppc <= 0) {
89 ignore_ppc = 0;
90 return 0;
93 if (ignore_ppc)
94 return 0;
96 if (event != CPUFREQ_INCOMPATIBLE)
97 return 0;
99 mutex_lock(&performance_mutex);
101 pr = per_cpu(processors, policy->cpu);
102 if (!pr || !pr->performance)
103 goto out;
105 ppc = (unsigned int)pr->performance_platform_limit;
107 if (ppc >= pr->performance->state_count)
108 goto out;
110 cpufreq_verify_within_limits(policy, 0,
111 pr->performance->states[ppc].
112 core_frequency * 1000);
114 out:
115 mutex_unlock(&performance_mutex);
117 return 0;
120 static struct notifier_block acpi_ppc_notifier_block = {
121 .notifier_call = acpi_processor_ppc_notifier,
124 static int acpi_processor_get_platform_limit(struct acpi_processor *pr)
126 acpi_status status = 0;
127 unsigned long long ppc = 0;
130 if (!pr)
131 return -EINVAL;
134 * _PPC indicates the maximum state currently supported by the platform
135 * (e.g. 0 = states 0..n; 1 = states 1..n; etc.
137 status = acpi_evaluate_integer(pr->handle, "_PPC", NULL, &ppc);
139 if (status != AE_NOT_FOUND)
140 acpi_processor_ppc_status |= PPC_IN_USE;
142 if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
143 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PPC"));
144 return -ENODEV;
147 cpufreq_printk("CPU %d: _PPC is %d - frequency %s limited\n", pr->id,
148 (int)ppc, ppc ? "" : "not");
150 pr->performance_platform_limit = (int)ppc;
152 return 0;
155 #define ACPI_PROCESSOR_NOTIFY_PERFORMANCE 0x80
157 * acpi_processor_ppc_ost: Notify firmware the _PPC evaluation status
158 * @handle: ACPI processor handle
159 * @status: the status code of _PPC evaluation
160 * 0: success. OSPM is now using the performance state specificed.
161 * 1: failure. OSPM has not changed the number of P-states in use
163 static void acpi_processor_ppc_ost(acpi_handle handle, int status)
165 union acpi_object params[2] = {
166 {.type = ACPI_TYPE_INTEGER,},
167 {.type = ACPI_TYPE_INTEGER,},
169 struct acpi_object_list arg_list = {2, params};
170 acpi_handle temp;
172 params[0].integer.value = ACPI_PROCESSOR_NOTIFY_PERFORMANCE;
173 params[1].integer.value = status;
175 /* when there is no _OST , skip it */
176 if (ACPI_FAILURE(acpi_get_handle(handle, "_OST", &temp)))
177 return;
179 acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
180 return;
183 int acpi_processor_ppc_has_changed(struct acpi_processor *pr, int event_flag)
185 int ret;
187 if (ignore_ppc) {
189 * Only when it is notification event, the _OST object
190 * will be evaluated. Otherwise it is skipped.
192 if (event_flag)
193 acpi_processor_ppc_ost(pr->handle, 1);
194 return 0;
197 ret = acpi_processor_get_platform_limit(pr);
199 * Only when it is notification event, the _OST object
200 * will be evaluated. Otherwise it is skipped.
202 if (event_flag) {
203 if (ret < 0)
204 acpi_processor_ppc_ost(pr->handle, 1);
205 else
206 acpi_processor_ppc_ost(pr->handle, 0);
208 if (ret < 0)
209 return (ret);
210 else
211 return cpufreq_update_policy(pr->id);
214 int acpi_processor_get_bios_limit(int cpu, unsigned int *limit)
216 struct acpi_processor *pr;
218 pr = per_cpu(processors, cpu);
219 if (!pr || !pr->performance || !pr->performance->state_count)
220 return -ENODEV;
221 *limit = pr->performance->states[pr->performance_platform_limit].
222 core_frequency * 1000;
223 return 0;
225 EXPORT_SYMBOL(acpi_processor_get_bios_limit);
227 void acpi_processor_ppc_init(void)
229 if (!cpufreq_register_notifier
230 (&acpi_ppc_notifier_block, CPUFREQ_POLICY_NOTIFIER))
231 acpi_processor_ppc_status |= PPC_REGISTERED;
232 else
233 printk(KERN_DEBUG
234 "Warning: Processor Platform Limit not supported.\n");
237 void acpi_processor_ppc_exit(void)
239 if (acpi_processor_ppc_status & PPC_REGISTERED)
240 cpufreq_unregister_notifier(&acpi_ppc_notifier_block,
241 CPUFREQ_POLICY_NOTIFIER);
243 acpi_processor_ppc_status &= ~PPC_REGISTERED;
246 static int acpi_processor_get_performance_control(struct acpi_processor *pr)
248 int result = 0;
249 acpi_status status = 0;
250 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
251 union acpi_object *pct = NULL;
252 union acpi_object obj = { 0 };
255 status = acpi_evaluate_object(pr->handle, "_PCT", NULL, &buffer);
256 if (ACPI_FAILURE(status)) {
257 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PCT"));
258 return -ENODEV;
261 pct = (union acpi_object *)buffer.pointer;
262 if (!pct || (pct->type != ACPI_TYPE_PACKAGE)
263 || (pct->package.count != 2)) {
264 printk(KERN_ERR PREFIX "Invalid _PCT data\n");
265 result = -EFAULT;
266 goto end;
270 * control_register
273 obj = pct->package.elements[0];
275 if ((obj.type != ACPI_TYPE_BUFFER)
276 || (obj.buffer.length < sizeof(struct acpi_pct_register))
277 || (obj.buffer.pointer == NULL)) {
278 printk(KERN_ERR PREFIX "Invalid _PCT data (control_register)\n");
279 result = -EFAULT;
280 goto end;
282 memcpy(&pr->performance->control_register, obj.buffer.pointer,
283 sizeof(struct acpi_pct_register));
286 * status_register
289 obj = pct->package.elements[1];
291 if ((obj.type != ACPI_TYPE_BUFFER)
292 || (obj.buffer.length < sizeof(struct acpi_pct_register))
293 || (obj.buffer.pointer == NULL)) {
294 printk(KERN_ERR PREFIX "Invalid _PCT data (status_register)\n");
295 result = -EFAULT;
296 goto end;
299 memcpy(&pr->performance->status_register, obj.buffer.pointer,
300 sizeof(struct acpi_pct_register));
302 end:
303 kfree(buffer.pointer);
305 return result;
308 static int acpi_processor_get_performance_states(struct acpi_processor *pr)
310 int result = 0;
311 acpi_status status = AE_OK;
312 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
313 struct acpi_buffer format = { sizeof("NNNNNN"), "NNNNNN" };
314 struct acpi_buffer state = { 0, NULL };
315 union acpi_object *pss = NULL;
316 int i;
319 status = acpi_evaluate_object(pr->handle, "_PSS", NULL, &buffer);
320 if (ACPI_FAILURE(status)) {
321 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PSS"));
322 return -ENODEV;
325 pss = buffer.pointer;
326 if (!pss || (pss->type != ACPI_TYPE_PACKAGE)) {
327 printk(KERN_ERR PREFIX "Invalid _PSS data\n");
328 result = -EFAULT;
329 goto end;
332 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d performance states\n",
333 pss->package.count));
335 pr->performance->state_count = pss->package.count;
336 pr->performance->states =
337 kmalloc(sizeof(struct acpi_processor_px) * pss->package.count,
338 GFP_KERNEL);
339 if (!pr->performance->states) {
340 result = -ENOMEM;
341 goto end;
344 for (i = 0; i < pr->performance->state_count; i++) {
346 struct acpi_processor_px *px = &(pr->performance->states[i]);
348 state.length = sizeof(struct acpi_processor_px);
349 state.pointer = px;
351 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Extracting state %d\n", i));
353 status = acpi_extract_package(&(pss->package.elements[i]),
354 &format, &state);
355 if (ACPI_FAILURE(status)) {
356 ACPI_EXCEPTION((AE_INFO, status, "Invalid _PSS data"));
357 result = -EFAULT;
358 kfree(pr->performance->states);
359 goto end;
362 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
363 "State [%d]: core_frequency[%d] power[%d] transition_latency[%d] bus_master_latency[%d] control[0x%x] status[0x%x]\n",
365 (u32) px->core_frequency,
366 (u32) px->power,
367 (u32) px->transition_latency,
368 (u32) px->bus_master_latency,
369 (u32) px->control, (u32) px->status));
372 * Check that ACPI's u64 MHz will be valid as u32 KHz in cpufreq
374 if (!px->core_frequency ||
375 ((u32)(px->core_frequency * 1000) !=
376 (px->core_frequency * 1000))) {
377 printk(KERN_ERR FW_BUG PREFIX
378 "Invalid BIOS _PSS frequency: 0x%llx MHz\n",
379 px->core_frequency);
380 result = -EFAULT;
381 kfree(pr->performance->states);
382 goto end;
386 end:
387 kfree(buffer.pointer);
389 return result;
392 static int acpi_processor_get_performance_info(struct acpi_processor *pr)
394 int result = 0;
395 acpi_status status = AE_OK;
396 acpi_handle handle = NULL;
398 if (!pr || !pr->performance || !pr->handle)
399 return -EINVAL;
401 status = acpi_get_handle(pr->handle, "_PCT", &handle);
402 if (ACPI_FAILURE(status)) {
403 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
404 "ACPI-based processor performance control unavailable\n"));
405 return -ENODEV;
408 result = acpi_processor_get_performance_control(pr);
409 if (result)
410 goto update_bios;
412 result = acpi_processor_get_performance_states(pr);
413 if (result)
414 goto update_bios;
416 return 0;
419 * Having _PPC but missing frequencies (_PSS, _PCT) is a very good hint that
420 * the BIOS is older than the CPU and does not know its frequencies
422 update_bios:
423 #ifdef CONFIG_X86
424 if (ACPI_SUCCESS(acpi_get_handle(pr->handle, "_PPC", &handle))){
425 if(boot_cpu_has(X86_FEATURE_EST))
426 printk(KERN_WARNING FW_BUG "BIOS needs update for CPU "
427 "frequency support\n");
429 #endif
430 return result;
433 int acpi_processor_notify_smm(struct module *calling_module)
435 acpi_status status;
436 static int is_done = 0;
439 if (!(acpi_processor_ppc_status & PPC_REGISTERED))
440 return -EBUSY;
442 if (!try_module_get(calling_module))
443 return -EINVAL;
445 /* is_done is set to negative if an error occured,
446 * and to postitive if _no_ error occured, but SMM
447 * was already notified. This avoids double notification
448 * which might lead to unexpected results...
450 if (is_done > 0) {
451 module_put(calling_module);
452 return 0;
453 } else if (is_done < 0) {
454 module_put(calling_module);
455 return is_done;
458 is_done = -EIO;
460 /* Can't write pstate_control to smi_command if either value is zero */
461 if ((!acpi_gbl_FADT.smi_command) || (!acpi_gbl_FADT.pstate_control)) {
462 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No SMI port or pstate_control\n"));
463 module_put(calling_module);
464 return 0;
467 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
468 "Writing pstate_control [0x%x] to smi_command [0x%x]\n",
469 acpi_gbl_FADT.pstate_control, acpi_gbl_FADT.smi_command));
471 status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
472 (u32) acpi_gbl_FADT.pstate_control, 8);
473 if (ACPI_FAILURE(status)) {
474 ACPI_EXCEPTION((AE_INFO, status,
475 "Failed to write pstate_control [0x%x] to "
476 "smi_command [0x%x]", acpi_gbl_FADT.pstate_control,
477 acpi_gbl_FADT.smi_command));
478 module_put(calling_module);
479 return status;
482 /* Success. If there's no _PPC, we need to fear nothing, so
483 * we can allow the cpufreq driver to be rmmod'ed. */
484 is_done = 1;
486 if (!(acpi_processor_ppc_status & PPC_IN_USE))
487 module_put(calling_module);
489 return 0;
492 EXPORT_SYMBOL(acpi_processor_notify_smm);
494 static int acpi_processor_get_psd(struct acpi_processor *pr)
496 int result = 0;
497 acpi_status status = AE_OK;
498 struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
499 struct acpi_buffer format = {sizeof("NNNNN"), "NNNNN"};
500 struct acpi_buffer state = {0, NULL};
501 union acpi_object *psd = NULL;
502 struct acpi_psd_package *pdomain;
504 status = acpi_evaluate_object(pr->handle, "_PSD", NULL, &buffer);
505 if (ACPI_FAILURE(status)) {
506 return -ENODEV;
509 psd = buffer.pointer;
510 if (!psd || (psd->type != ACPI_TYPE_PACKAGE)) {
511 printk(KERN_ERR PREFIX "Invalid _PSD data\n");
512 result = -EFAULT;
513 goto end;
516 if (psd->package.count != 1) {
517 printk(KERN_ERR PREFIX "Invalid _PSD data\n");
518 result = -EFAULT;
519 goto end;
522 pdomain = &(pr->performance->domain_info);
524 state.length = sizeof(struct acpi_psd_package);
525 state.pointer = pdomain;
527 status = acpi_extract_package(&(psd->package.elements[0]),
528 &format, &state);
529 if (ACPI_FAILURE(status)) {
530 printk(KERN_ERR PREFIX "Invalid _PSD data\n");
531 result = -EFAULT;
532 goto end;
535 if (pdomain->num_entries != ACPI_PSD_REV0_ENTRIES) {
536 printk(KERN_ERR PREFIX "Unknown _PSD:num_entries\n");
537 result = -EFAULT;
538 goto end;
541 if (pdomain->revision != ACPI_PSD_REV0_REVISION) {
542 printk(KERN_ERR PREFIX "Unknown _PSD:revision\n");
543 result = -EFAULT;
544 goto end;
547 if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
548 pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
549 pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
550 printk(KERN_ERR PREFIX "Invalid _PSD:coord_type\n");
551 result = -EFAULT;
552 goto end;
554 end:
555 kfree(buffer.pointer);
556 return result;
559 int acpi_processor_preregister_performance(
560 struct acpi_processor_performance *performance)
562 int count, count_target;
563 int retval = 0;
564 unsigned int i, j;
565 cpumask_var_t covered_cpus;
566 struct acpi_processor *pr;
567 struct acpi_psd_package *pdomain;
568 struct acpi_processor *match_pr;
569 struct acpi_psd_package *match_pdomain;
571 if (!zalloc_cpumask_var(&covered_cpus, GFP_KERNEL))
572 return -ENOMEM;
574 mutex_lock(&performance_mutex);
577 * Check if another driver has already registered, and abort before
578 * changing pr->performance if it has. Check input data as well.
580 for_each_possible_cpu(i) {
581 pr = per_cpu(processors, i);
582 if (!pr) {
583 /* Look only at processors in ACPI namespace */
584 continue;
587 if (pr->performance) {
588 retval = -EBUSY;
589 goto err_out;
592 if (!performance || !per_cpu_ptr(performance, i)) {
593 retval = -EINVAL;
594 goto err_out;
598 /* Call _PSD for all CPUs */
599 for_each_possible_cpu(i) {
600 pr = per_cpu(processors, i);
601 if (!pr)
602 continue;
604 pr->performance = per_cpu_ptr(performance, i);
605 cpumask_set_cpu(i, pr->performance->shared_cpu_map);
606 if (acpi_processor_get_psd(pr)) {
607 retval = -EINVAL;
608 continue;
611 if (retval)
612 goto err_ret;
615 * Now that we have _PSD data from all CPUs, lets setup P-state
616 * domain info.
618 for_each_possible_cpu(i) {
619 pr = per_cpu(processors, i);
620 if (!pr)
621 continue;
623 if (cpumask_test_cpu(i, covered_cpus))
624 continue;
626 pdomain = &(pr->performance->domain_info);
627 cpumask_set_cpu(i, pr->performance->shared_cpu_map);
628 cpumask_set_cpu(i, covered_cpus);
629 if (pdomain->num_processors <= 1)
630 continue;
632 /* Validate the Domain info */
633 count_target = pdomain->num_processors;
634 count = 1;
635 if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)
636 pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ALL;
637 else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
638 pr->performance->shared_type = CPUFREQ_SHARED_TYPE_HW;
639 else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
640 pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ANY;
642 for_each_possible_cpu(j) {
643 if (i == j)
644 continue;
646 match_pr = per_cpu(processors, j);
647 if (!match_pr)
648 continue;
650 match_pdomain = &(match_pr->performance->domain_info);
651 if (match_pdomain->domain != pdomain->domain)
652 continue;
654 /* Here i and j are in the same domain */
656 if (match_pdomain->num_processors != count_target) {
657 retval = -EINVAL;
658 goto err_ret;
661 if (pdomain->coord_type != match_pdomain->coord_type) {
662 retval = -EINVAL;
663 goto err_ret;
666 cpumask_set_cpu(j, covered_cpus);
667 cpumask_set_cpu(j, pr->performance->shared_cpu_map);
668 count++;
671 for_each_possible_cpu(j) {
672 if (i == j)
673 continue;
675 match_pr = per_cpu(processors, j);
676 if (!match_pr)
677 continue;
679 match_pdomain = &(match_pr->performance->domain_info);
680 if (match_pdomain->domain != pdomain->domain)
681 continue;
683 match_pr->performance->shared_type =
684 pr->performance->shared_type;
685 cpumask_copy(match_pr->performance->shared_cpu_map,
686 pr->performance->shared_cpu_map);
690 err_ret:
691 for_each_possible_cpu(i) {
692 pr = per_cpu(processors, i);
693 if (!pr || !pr->performance)
694 continue;
696 /* Assume no coordination on any error parsing domain info */
697 if (retval) {
698 cpumask_clear(pr->performance->shared_cpu_map);
699 cpumask_set_cpu(i, pr->performance->shared_cpu_map);
700 pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ALL;
702 pr->performance = NULL; /* Will be set for real in register */
705 err_out:
706 mutex_unlock(&performance_mutex);
707 free_cpumask_var(covered_cpus);
708 return retval;
710 EXPORT_SYMBOL(acpi_processor_preregister_performance);
713 acpi_processor_register_performance(struct acpi_processor_performance
714 *performance, unsigned int cpu)
716 struct acpi_processor *pr;
718 if (!(acpi_processor_ppc_status & PPC_REGISTERED))
719 return -EINVAL;
721 mutex_lock(&performance_mutex);
723 pr = per_cpu(processors, cpu);
724 if (!pr) {
725 mutex_unlock(&performance_mutex);
726 return -ENODEV;
729 if (pr->performance) {
730 mutex_unlock(&performance_mutex);
731 return -EBUSY;
734 WARN_ON(!performance);
736 pr->performance = performance;
738 if (acpi_processor_get_performance_info(pr)) {
739 pr->performance = NULL;
740 mutex_unlock(&performance_mutex);
741 return -EIO;
744 mutex_unlock(&performance_mutex);
745 return 0;
748 EXPORT_SYMBOL(acpi_processor_register_performance);
750 void
751 acpi_processor_unregister_performance(struct acpi_processor_performance
752 *performance, unsigned int cpu)
754 struct acpi_processor *pr;
756 mutex_lock(&performance_mutex);
758 pr = per_cpu(processors, cpu);
759 if (!pr) {
760 mutex_unlock(&performance_mutex);
761 return;
764 if (pr->performance)
765 kfree(pr->performance->states);
766 pr->performance = NULL;
768 mutex_unlock(&performance_mutex);
770 return;
773 EXPORT_SYMBOL(acpi_processor_unregister_performance);