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SubjectRe: cpufreq notifiers break suspend -- Re: suspend broken in next-20190704 on Thinkpad X60
On Mon, Jul 8, 2019 at 11:28 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> On 08-07-19, 10:28, Rafael J. Wysocki wrote:
> > Pavel has tested the latest version of the patch series AFAICS.
> >
> > The locking added by the commit in question to
> > refresh_frequency_limits() requires an update of
> > cpufreq_update_policy(), or it will deadlock in there because of the
> > lock acquired by cpufreq_cpu_get() if I haven't missed anything.
>
> Ah, looks quite straight forward.
>
> @Pavel: Can you please try this diff ?
>
> -------------------------8<-------------------------
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 9f68d0f306b8..4d6043ee7834 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1109,16 +1109,12 @@ void refresh_frequency_limits(struct cpufreq_policy *policy)
> {
> struct cpufreq_policy new_policy;
>
> - down_write(&policy->rwsem);
> -
> if (!policy_is_inactive(policy)) {
> new_policy = *policy;
> pr_debug("updating policy for CPU %u\n", policy->cpu);
>
> cpufreq_set_policy(policy, &new_policy);
> }
> -
> - up_write(&policy->rwsem);
> }
> EXPORT_SYMBOL(refresh_frequency_limits);
>
> @@ -1128,7 +1124,9 @@ static void handle_update(struct work_struct *work)
> container_of(work, struct cpufreq_policy, update);
>
> pr_debug("handle_update for cpu %u called\n", policy->cpu);
> + down_write(&policy->rwsem);
> refresh_frequency_limits(policy);
> + up_write(&policy->rwsem);
> }
>
> -------------------------8<-------------------------
>
> Though it makes me wonder why I didn't hit this thing. I was using the
> cpu_cooling device the other day, which calls cpufreq_update_policy()
> very frequently on heat-up. And I had a hair dryer blowing over my
> board to heat it up. Lemme check that again :)
>
> @Rafael: You want me to send a new diff patch with Fixes tag this time
> if this works out fine ?

I would prefer the original patch to be updated to avoid possible
bisection woes in the future.

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