1. 10 7月, 2015 1 次提交
    • V
      cpufreq: Initialize the governor again while restoring policy · 35afd02e
      Viresh Kumar 提交于
      When all CPUs of a policy are hot-unplugged, we EXIT the governor but
      don't mark policy->governor as NULL. This was done in order to keep last
      used governor's information intact in sysfs, while the CPUs are offline.
      
      But we also need to clear policy->governor when restoring the policy.
      
      Because policy->governor still points to the last governor while policy
      is restored, following sequence of event happens:
       - cpufreq_init_policy() called while restoring policy
       - find_governor() matches last_governor string for present governors and
         returns last used governor's pointer, say ondemand. policy->governor
         already has the same address, unless the governor was removed in
         between.
       - cpufreq_set_policy() is called with both old/new policies governor set
         as ondemand.
       - Because governors matched, we skip governor initialization and return
         after calling __cpufreq_governor(CPUFREQ_GOV_LIMITS). Because the
         governor wasn't initialized for this policy, it returned -EBUSY.
       - cpufreq_init_policy() exits the policy on this error, but doesn't
         destroy it properly (should be fixed separately).
       - And so we enter a scenario where the policy isn't completely
         initialized but used.
      
      Fix this by setting policy->governor to NULL while restoring the policy.
      Reported-and-tested-by: NPi-Cheng Chen <pi-cheng.chen@linaro.org>
      Reported-and-tested-by: N"Jon Medhurst (Tixy)" <tixy@linaro.org>
      Reported-and-tested-by: NSteven Rostedt <rostedt@goodmis.org>
      Fixes: 18bf3a12 (cpufreq: Mark policy->governor = NULL for inactive policies)
      Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
      Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      35afd02e
  2. 05 7月, 2015 21 次提交
  3. 04 7月, 2015 3 次提交
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  5. 02 7月, 2015 10 次提交