On Monday, April 15, 2013 10:52:28 PM Viresh Kumar wrote:
> On 15 April 2013 21:37, Dirk Brandewie <dirk.brandewie@xxxxxxxxx> wrote:
> > If the intel_pstate driver is being used __cpufreq_governor() should NOT be
> > called intel_pstate does not implement the target() callback.
> >
> > Nathan's commit 5800043b2 changed the fence around the call to
> > __cpufreq_governor() in __cpufreq_remove_dev() here is the relevant hunk.
>
> No it isn't.
>
> > + if (has_target)
> > __cpufreq_governor(data, CPUFREQ_GOV_STOP);
>
> As it has taken care of this limitation.
>
> BUT some of my earlier patches haven't. :(
> Here is the fix (Sedat please try this and give your tested-by, use the attached
> patch as gmail might break what i am copying in mail)..
>
> Sorry for being late in fixing this issue, i am still down with Tonsil infection
> and fever.. Today only i got some power to fix it after seeing Dirk's mail.
>
> Your tested-by may help me to recover quickly :)
>
> @Rafael: I will probably be down for one more week and so not doing any
> reviews for now... I do check important mails sent directly to me though.
>
> ------------x----------------------x------------------
>
> From: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
> Date: Mon, 15 Apr 2013 22:43:57 +0530
> Subject: [PATCH] cpufreq: Don't call __cpufreq_governor() for drivers without
> target()
>
> Some cpufreq drivers implement their own governor and so don't need us to call
> generic governors interface via __cpufreq_governor(). Few recent commits haven't
> obeyed this law well and we saw some regressions.
>
> This patch tries to fix this issue.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Applied to linux-pm.git/linux-next, although please check the result, because
the patchwork version of the patch wasn't quite applicable and I fixed it up
manually.
Thanks,
Rafael
> ---
> drivers/cpufreq/cpufreq.c | 18 +++++++++++++-----
> 1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 3564947..a6f6595 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -858,13 +858,18 @@ static int cpufreq_add_policy_cpu(unsigned int
> cpu, unsigned int sibling,
> struct device *dev)
> {
> struct cpufreq_policy *policy;
> - int ret = 0;
> + int ret = 0, has_target = 0;
> unsigned long flags;
>
> policy = cpufreq_cpu_get(sibling);
> WARN_ON(!policy);
>
> - __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
> + rcu_read_lock();
> + has_target = !!rcu_dereference(cpufreq_driver)->target;
> + rcu_read_unlock();
> +
> + if (has_target)
> + __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
>
> lock_policy_rwsem_write(sibling);
>
> @@ -877,8 +882,10 @@ static int cpufreq_add_policy_cpu(unsigned int
> cpu, unsigned int sibling,
>
> unlock_policy_rwsem_write(sibling);
>
> - __cpufreq_governor(policy, CPUFREQ_GOV_START);
> - __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
> + if (has_target) {
> + __cpufreq_governor(policy, CPUFREQ_GOV_START);
> + __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
> + }
>
> ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
> if (ret) {
> @@ -1146,7 +1153,8 @@ static int __cpufreq_remove_dev(struct device
> *dev, struct subsys_interface *sif
>
> /* If cpu is last user of policy, free policy */
> if (cpus == 1) {
> - __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
> + if (has_target)
> + __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
>
> lock_policy_rwsem_read(cpu);
> kobj = &data->kobj;
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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