From 798282a8718347b04a2f0a4bae7d775c48c6bcb9 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 10 Sep 2013 02:54:50 +0200 Subject: 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: [] dump_stack+0x46/0x58 [] warn_slowpath_common+0x8c/0xc0 [] ? acpi_cpufreq_target+0x320/0x320 [] warn_slowpath_fmt+0x46/0x50 [] __cpufreq_notify_transition+0x238/0x260 [] cpufreq_notify_transition+0x3e/0x70 [] cpufreq_out_of_sync+0x6d/0xb0 [] cpufreq_update_policy+0x10c/0x160 [] ? cpufreq_update_policy+0x160/0x160 [] cpufreq_set_cur_state+0x8c/0xb5 [] processor_set_cur_state+0xa3/0xcf [] thermal_cdev_update+0x9c/0xb0 [] step_wise_throttle+0x5a/0x90 [] handle_thermal_trip+0x4f/0x140 [] thermal_zone_device_update+0x57/0xa0 [] acpi_thermal_check+0x2e/0x30 [] acpi_thermal_notify+0x40/0xdc [] acpi_device_notify+0x19/0x1b [] acpi_ev_notify_dispatch+0x41/0x5c [] acpi_os_execute_deferred+0x25/0x32 [] process_one_work+0x170/0x4a0 [] worker_thread+0x121/0x390 [] ? manage_workers.isra.20+0x170/0x170 [] kthread+0xc0/0xd0 [] ? flush_kthread_worker+0xb0/0xb0 [] ret_from_fork+0x7c/0xb0 [] ? 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 Signed-off-by: Rafael J. Wysocki --- include/linux/cpufreq.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include') diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index d568f3975eeb..fcabc42d66ab 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -85,7 +85,6 @@ struct cpufreq_policy { struct list_head policy_list; struct kobject kobj; struct completion kobj_unregister; - int transition_ongoing; /* Tracks transition status */ }; /* Only for ACPI */ -- cgit v1.2.3