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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-09-10 02:54:50 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-09-10 02:54:50 +0200
commit798282a8718347b04a2f0a4bae7d775c48c6bcb9 (patch)
treefd296df6b0ad8fb74de6aeedbaa83ca1cff941e0 /drivers/cpufreq
parent5136fa56582beadb7fa71eb30bc79148bfcba5c1 (diff)
downloadlinux-798282a8718347b04a2f0a4bae7d775c48c6bcb9.tar.bz2
Revert "cpufreq: make sure frequency transitions are serialized"
Commit 7c30ed5 (cpufreq: make sure frequency transitions are serialized) attempted to serialize frequency transitions by adding checks to the CPUFREQ_PRECHANGE and CPUFREQ_POSTCHANGE notifications. However, it assumed that the notifications will always originate from the driver's .target() callback, but they also can be triggered by cpufreq_out_of_sync() and that leads to warnings like this on some systems: WARNING: CPU: 0 PID: 14543 at drivers/cpufreq/cpufreq.c:317 __cpufreq_notify_transition+0x238/0x260() In middle of another frequency transition accompanied by a call trace similar to this one: [<ffffffff81720daa>] dump_stack+0x46/0x58 [<ffffffff8106534c>] warn_slowpath_common+0x8c/0xc0 [<ffffffff815b8560>] ? acpi_cpufreq_target+0x320/0x320 [<ffffffff81065436>] warn_slowpath_fmt+0x46/0x50 [<ffffffff815b1ec8>] __cpufreq_notify_transition+0x238/0x260 [<ffffffff815b33be>] cpufreq_notify_transition+0x3e/0x70 [<ffffffff815b345d>] cpufreq_out_of_sync+0x6d/0xb0 [<ffffffff815b370c>] cpufreq_update_policy+0x10c/0x160 [<ffffffff815b3760>] ? cpufreq_update_policy+0x160/0x160 [<ffffffff81413813>] cpufreq_set_cur_state+0x8c/0xb5 [<ffffffff814138df>] processor_set_cur_state+0xa3/0xcf [<ffffffff8158e13c>] thermal_cdev_update+0x9c/0xb0 [<ffffffff8159046a>] step_wise_throttle+0x5a/0x90 [<ffffffff8158e21f>] handle_thermal_trip+0x4f/0x140 [<ffffffff8158e377>] thermal_zone_device_update+0x57/0xa0 [<ffffffff81415b36>] acpi_thermal_check+0x2e/0x30 [<ffffffff81415ca0>] acpi_thermal_notify+0x40/0xdc [<ffffffff813e7dbd>] acpi_device_notify+0x19/0x1b [<ffffffff813f8241>] acpi_ev_notify_dispatch+0x41/0x5c [<ffffffff813e3fbe>] acpi_os_execute_deferred+0x25/0x32 [<ffffffff81081060>] process_one_work+0x170/0x4a0 [<ffffffff81082121>] worker_thread+0x121/0x390 [<ffffffff81082000>] ? manage_workers.isra.20+0x170/0x170 [<ffffffff81088fe0>] kthread+0xc0/0xd0 [<ffffffff81088f20>] ? flush_kthread_worker+0xb0/0xb0 [<ffffffff8173582c>] ret_from_fork+0x7c/0xb0 [<ffffffff81088f20>] ? flush_kthread_worker+0xb0/0xb0 For this reason, revert commit 7c30ed5 along with the fix 266c13d (cpufreq: Fix serialization of frequency transitions) on top of it and we will revisit the serialization problem later. Reported-by: Alessandro Bono <alessandro.bono@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/cpufreq.c15
1 files changed, 0 insertions, 15 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 73d53d5a16ee..5a64f66d36e0 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -280,13 +280,6 @@ static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
switch (state) {
case CPUFREQ_PRECHANGE:
- if (WARN(policy->transition_ongoing ==
- cpumask_weight(policy->cpus),
- "In middle of another frequency transition\n"))
- return;
-
- policy->transition_ongoing++;
-
/* detect if the driver reported a value as "old frequency"
* which is not equal to what the cpufreq core thinks is
* "old frequency".
@@ -306,12 +299,6 @@ static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
break;
case CPUFREQ_POSTCHANGE:
- if (WARN(!policy->transition_ongoing,
- "No frequency transition in progress\n"))
- return;
-
- policy->transition_ongoing--;
-
adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new,
(unsigned long)freqs->cpu);
@@ -1657,8 +1644,6 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
if (cpufreq_disabled())
return -ENODEV;
- if (policy->transition_ongoing)
- return -EBUSY;
/* Make sure that target_freq is within supported range */
if (target_freq > policy->max)