Re: [PATCH v2 4/4] cpufreq: Use policy->min/max init as QoS request

[Pierre Gondois]

Hello Jie,

On 5/20/26 10:38, Jie Zhan wrote:
> On 5/11/2026 9:55 PM, Pierre Gondois wrote:
> > Consider policy->min/max being set in the driver .init()
> > callback as a QoS request. Impacted driver are:
> > - gx-suspmod.c (min)
> > - cppc-cpufreq.c (min)
> > - longrun.c (min/max)
> >
> > Update the documentation accordingly.
> >
> > Signed-off-by: Pierre Gondois<pierre.gondois@xxxxxxx>
> > ---
> >   Documentation/cpu-freq/cpu-drivers.rst | 10 ++++++++--
> >   drivers/cpufreq/cpufreq.c              | 12 ++++++++++--
> >   2 files changed, 18 insertions(+), 4 deletions(-)
> >
> > diff --git a/Documentation/cpu-freq/cpu-drivers.rst b/Documentation/cpu-freq/cpu-drivers.rst
> > index c5635ac3de547..ab4f3c0f3a89b 100644
> > --- a/Documentation/cpu-freq/cpu-drivers.rst
> > +++ b/Documentation/cpu-freq/cpu-drivers.rst
> > @@ -114,8 +114,14 @@ Then, the driver must fill in the following values:
> >   |policy->cur			    | The current operating frequency of   |
> >   |				    | this CPU (if appropriate)		   |
> >   +-----------------------------------+--------------------------------------+
> > -|policy->min,			    |					   |
> > -|policy->max,			    |					   |
> > +|policy->min			    | If set by the driver in ->init(),    |
> > +|				    | used as initial minimum frequency	   |
> > +|				    | QoS request.			   |
> > ++-----------------------------------+--------------------------------------+
> > +|policy->max			    | If set by the driver in ->init(),    |
> > +|				    | used as initial maximum frequency	   |
> > +|				    | QoS request.			   |
> > ++-----------------------------------+--------------------------------------+
> Hi Pierre,
>
> Trivial bit: add the general meaning alongside its driver usage at the init
> stage, and mention it defaults to cpuinfo_min/max_freq if not set?
>
> I mean something like:
> The minimum/maximum scaling frequency.  If set by the driver in ->init(),
> used as initial minimum/maximum frequency QoS request; otherwise, follow
> policy->cpuinfo.min/max_freq.

Just one NIT, policy->min/max should follow the min/max allowed freq.

the cpufreq driver can set. E.g. a thermal constraint can impact it (cf. 
dtpm_cpu.c).

Would this fit ?

The minimum/maximum scaling frequency.  If set by the driver in ->init(),
used as initial minimum/maximum frequency QoS request; otherwise, follow
the min/max allowed freq. the cpufreq driver can set.


> Thanks,
> Jie
> >   |policy->policy and, if necessary,  |					   |
> >   |policy->governor		    | must contain the "default policy" for|
> >   |				    | this CPU. A few moments later,       |
> [ ... ]