RE: [PATCH v10 5/8] cpufreq: amd-pstate: Bail out if min/max/nominal_freq is 0

[Yuan, Perry]

[AMD Official Use Only - General]

Regards.
Perry

> -----Original Message-----
> From: Huang, Ray <Ray.Huang@xxxxxxx>
> Sent: Monday, April 15, 2024 10:59 PM
> To: Yuan, Perry <Perry.Yuan@xxxxxxx>
> Cc: rafael.j.wysocki@xxxxxxxxx; Limonciello, Mario
> <Mario.Limonciello@xxxxxxx>; viresh.kumar@xxxxxxxxxx; Shenoy, Gautham
> Ranjal <gautham.shenoy@xxxxxxx>; Petkov, Borislav
> <Borislav.Petkov@xxxxxxx>; Deucher, Alexander
> <Alexander.Deucher@xxxxxxx>; Huang, Shimmer
> <Shimmer.Huang@xxxxxxx>; oleksandr@xxxxxxxxxxxxxx; Du, Xiaojian
> <Xiaojian.Du@xxxxxxx>; Meng, Li (Jassmine) <Li.Meng@xxxxxxx>; linux-
> pm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v10 5/8] cpufreq: amd-pstate: Bail out if
> min/max/nominal_freq is 0
>
> On Mon, Mar 25, 2024 at 11:03:25AM +0800, Yuan, Perry wrote:
> > The amd-pstate driver cannot work when the min_freq, nominal_freq or
> > the max_freq is zero. When this happens it is prudent to error out
> > early on rather than waiting failing at the time of the governor
> > initialization.
> >
> > Reviewed-by: Gautham R. Shenoy <gautham.shenoy@xxxxxxx>
> > Tested-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@xxxxxxx>
> > Signed-off-by: Perry Yuan <perry.yuan@xxxxxxx>
> > ---
> >  drivers/cpufreq/amd-pstate.c | 16 ++++++++++------
> >  1 file changed, 10 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c
> > b/drivers/cpufreq/amd-pstate.c index 132330b4942f..6708c436e1a2
> 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -839,9 +839,11 @@ static int amd_pstate_cpu_init(struct
> cpufreq_policy *policy)
> >     nominal_freq = READ_ONCE(cpudata->nominal_freq);
> >     lowest_nonlinear_freq = READ_ONCE(cpudata-
> >lowest_nonlinear_freq);
> >
> > -   if (min_freq < 0 || max_freq < 0 || min_freq > max_freq) {
> > -           dev_err(dev, "min_freq(%d) or max_freq(%d) value is
> incorrect\n",
> > -                   min_freq, max_freq);
> > +   if (min_freq <= 0 || max_freq <= 0 ||
> > +       nominal_freq <= 0 || min_freq > max_freq) {
> > +           dev_err(dev,
> > +                   "min_freq(%d) or max_freq(%d) or nominal_freq
> (%d) value is incorrect\n",
> > +                   min_freq, max_freq, nominal_freq);
>
> I suggest that we add one comment to remind that should be the error of
> ACPI table or BIOS.

 Ok, thanks for comment,  will add one more comment in v11.

>
> >             ret = -EINVAL;
> >             goto free_cpudata1;
> >     }
> > @@ -1299,9 +1301,11 @@ static int amd_pstate_epp_cpu_init(struct
> cpufreq_policy *policy)
> >     max_freq = READ_ONCE(cpudata->max_freq);
> >     nominal_freq = READ_ONCE(cpudata->nominal_freq);
> >     lowest_nonlinear_freq = READ_ONCE(cpudata-
> >lowest_nonlinear_freq);
> > -   if (min_freq < 0 || max_freq < 0 || min_freq > max_freq) {
> > -           dev_err(dev, "min_freq(%d) or max_freq(%d) value is
> incorrect\n",
> > -                           min_freq, max_freq);
> > +   if (min_freq <= 0 || max_freq <= 0 ||
> > +       nominal_freq <= 0 || min_freq > max_freq) {
> > +           dev_err(dev,
> > +                   "min_freq(%d) or max_freq(%d) or nominal_freq(%d)
> value is incorrect\n",
> > +                   min_freq, max_freq, nominal_freq);
>
> The same with above.
>
> With that fixed, patch is Acked-by: Huang Rui <ray.huang@xxxxxxx>
>
> Thanks,
> Ray

Thanks for the ACK.

Perry.