Re: [PATCH V3 1/6] cpufreq: suspend governors on system suspend/hibernate

On 26 November 2013 04:59, Rafael J. Wysocki rjw@rjwysocki.net wrote:

...

@@ -1259,6 +1262,8 @@ int dpm_suspend(pm_message_t state)

  might_sleep();

• cpufreq_suspend();
  

• mutex_lock(&dpm_list_mtx);
  pm_transition = state;
  async_error = 0;
  

Shouldn't it do cpufreq_resume() on errors?

Yes and this is already done I believe. In case dpm_suspend() fails, dpm_resume() gets called. Isn't it?

...

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c +void cpufreq_suspend(void) +{

• struct cpufreq_policy *policy;
  

• if (!has_target())
  

•         return;
  

• pr_debug("%s: Suspending Governors\n", __func__);
  

• list_for_each_entry(policy, &cpufreq_policy_list, policy_list)
  

•         if (__cpufreq_governor(policy, CPUFREQ_GOV_STOP))
  

•                 pr_err("%s: Failed to stop governor for policy: %p\n",
  

•                                 __func__, policy);
  

This appears to be racy. Is it really racy, or just seemingly?

Why does it look racy to you? Userspace should be frozen by now, policy_list should be stable as well as nobody would touch it.