Re: [PATCH 1/1] cpufreq: Set policy->min and max as real QoS constraints

[Pierre Gondois]

Hello Sumit,

On 4/28/26 18:37, Sumit Gupta wrote:
> On 23/04/26 14:17, Pierre Gondois wrote:
> > External email: Use caution opening links or attachments
> >
> >
> > cpufreq_set_policy() will ultimately override the policy min/max
> > values written in the .init() callback through:
> > cpufreq_policy_online()
> > \-cpufreq_init_policy()
> >    \-cpufreq_set_policy()
> >      \-/* Set policy->min/max */
> > Thus the policy min/max values provided are only temporary.
> >
> > There is an exception if CPUFREQ_NEED_INITIAL_FREQ_CHECK is set and:
> > cpufreq_policy_online()
> > \-cpufreq_init_policy()
> >    \-__cpufreq_driver_target()
> >      \-cpufreq_driver->target()
> > is called. To avoid any regression, set policy->min/max in cpufreq.c
> > if the values were not initialized.
> >
> > In this patch:
> > - Setting policy->min or max value in driver .init() cb is
> >    interpreted as setting a QoS constraint.
> > - Remove policy->min/max initialization in drivers if the values
> >    are similar to policy->cpuinfo.min_freq/max_freq.
> >    The only drivers where these values are different are:
> >    - gx-suspmod.c
> >    - cppc-cpufreq.c
> >    - longrun.c
> > - For the cppc-cpufreq driver, the lowest non-linear freq. is
> >    used as a min QoS constraint as suggested at:
> > https://lore.kernel.org/lkml/20260213100633.15413-1-zhangpengjie2@xxxxxxxxxx/
> >
> > Signed-off-by: Pierre Gondois <pierre.gondois@xxxxxxx>
>
> Tested-by: Sumit Gupta <sumitg@xxxxxxxxxx>
> Reviewed-by: Sumit Gupta <sumitg@xxxxxxxxxx>
Thanks!
There might be a v2 with some small modifications.