On Friday, May 25, 2018 4:54:04 AM CEST Wangtao (Kevin, Kirin) wrote: > > 在 2018/5/24 15:45, Rafael J. Wysocki 写道: > > On Thu, May 24, 2018 at 8:43 AM, Kevin Wangtao > > <[email protected]> wrote: > >> consider such situation, current user_policy.min is 1000000, > >> current user_policy.max is 1200000, in cpufreq_set_policy, > >> other driver may update policy.min to 1200000, policy.max to > >> 1300000. After that, If we input "echo 1300000 > scaling_min_freq", > >> then user_policy.min will be 1300000, and user_policy.max is > >> still 1200000, because the input value is checked with policy.max > >> not user_policy.max. if we get all related cpus offline and > >> online again, it will cause cpufreq_init_policy fail because > >> user_policy.min is higher than user_policy.max. > > > > How do you reproduce this, exactly? > > I write a driver register CPUFREQ_POLICY_NOTIFIER, and when event is > CPUFREQ_ADJUST, > it will modify policy's min/max according to some conditions, I test it with > writing > scaling_(max|min)_freq to traverse all frequencies repeatly, and also repeat > hotplug > as background.
You are expected to use cpufreq_update_policy() to update the limits in policy notifiers. Do you use it in your driver?
