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Venkatesh Pallipadi 4ec223d02f [CPUFREQ] Fix ondemand vs suspend deadlock ... Rootcaused the bug to a deadlock in cpufreq and ondemand. Due to non-existent ordering between cpu_hotplug lock and dbs_mutex. Basically a race condition between cpu_down() and do_dbs_timer(). cpu_down() flow: * cpu_down() call for CPU 1 * Takes hot plug lock * Calls pre down notifier * cpufreq notifier handler calls cpufreq_driver_target() which takes cpu_hotplug lock again. OK as cpu_hotplug lock is recursive in same process context * CPU 1 goes down * Calls post down notifier * cpufreq notifier handler calls ondemand event stop which takes dbs_mutex So, cpu_hotplug lock is taken before dbs_mutex in this flow. do_dbs_timer is triggerred by a periodic timer event. It first takes dbs_mutex and then takes cpu_hotplug lock in cpufreq_driver_target(). Note the reverse order here compared to above. So, if this timer event happens at right moment during cpu_down, system will deadlok. Attached patch fixes the issue for both ondemand and conservative. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>		19 years ago
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Kconfig	[CPUFREQ] Update LART site URL	19 years ago
Makefile	[CPUFREQ] Conservative cpufreq governer	20 years ago
cpufreq.c	[CPUFREQ] cpufreq core {d,}printk adjustments	19 years ago
cpufreq_conservative.c	[CPUFREQ] Fix ondemand vs suspend deadlock	19 years ago
cpufreq_ondemand.c	[CPUFREQ] Fix ondemand vs suspend deadlock	19 years ago
cpufreq_performance.c	[CPUFREQ] Lots of whitespace & CodingStyle cleanup.	19 years ago
cpufreq_powersave.c	[CPUFREQ] Lots of whitespace & CodingStyle cleanup.	19 years ago
cpufreq_stats.c	[CPUFREQ] CodingStyle nits in cpufreq_stats.c	19 years ago
cpufreq_userspace.c	[CPUFREQ] Lots of whitespace & CodingStyle cleanup.	19 years ago
freq_table.c	[CPUFREQ] Remove more freq_table reinitialisations.	19 years ago