Re: [PATCH V2] cpufreq: reinitialize new policy min/max when writing scaling_(max|min)_freq

[Wangtao (Kevin, Kirin)]

在 2018/5/29 18:26, Viresh Kumar 写道:
> On 26-05-18, 15:16, Kevin Wangtao 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.
> >
> > The solution is when user space tries to write scaling_(max|min)_freq,
> > the min/max of new_policy should be reinitialized with min/max
> > of user_policy, like what cpufreq_update_policy does.
> >
> > Signed-off-by: Kevin Wangtao <kevin.wangtao@xxxxxxxxxxxxx>
> > ---
> >   drivers/cpufreq/cpufreq.c | 2 ++
> >   1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> > index b79c532..82123a1 100644
> > --- a/drivers/cpufreq/cpufreq.c
> > +++ b/drivers/cpufreq/cpufreq.c
> > @@ -697,6 +697,8 @@ static ssize_t store_##file_name					\
> >   	struct cpufreq_policy new_policy;				\
> >   									\
> >   	memcpy(&new_policy, policy, sizeof(*policy));			\
>
> Maybe add a comment here on why this is required ?
OK
> > +	new_policy.min = policy->user_policy.min;			\
> > +	new_policy.max = policy->user_policy.max;			\
> >   									\
> >   	ret = sscanf(buf, "%u", &new_policy.object);			\
> >   	if (ret != 1)							\
>
> Acked-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>