Re: [PATCH v3 01/18] cpufreq/amd-pstate: Invalidate cppc_req_cached during suspend

[Mario Limonciello]

On 2/18/2025 23:24, Gautham R. Shenoy wrote:
> Hello Mario,
>
>
> On Mon, Feb 17, 2025 at 04:06:50PM -0600, Mario Limonciello wrote:
> > From: Mario Limonciello <mario.limonciello@xxxxxxx>
> >
> > During resume it's possible the firmware didn't restore the CPPC request MSR
> > but the kernel thinks the values line up. This leads to incorrect performance
> > after resume from suspend.
> >
> > To fix the issue invalidate the cached value at suspend. During resume use
> > the saved values programmed as cached limits.
> >
> > Reported-by: Miroslav Pavleski <miroslav@xxxxxxxxxxxx>
> > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217931
> > Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> > ---
> >   drivers/cpufreq/amd-pstate.c | 5 ++++-
> >   1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> > index f425fb7ec77d7..12fb63169a24c 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -1611,7 +1611,7 @@ static int amd_pstate_epp_reenable(struct cpufreq_policy *policy)
> >   					  max_perf, policy->boost_enabled);
> >   	}
>
> You can also remove the tracing code from amd_pstate_epp_reenable(), i.e,
>
> 	if (trace_amd_pstate_epp_perf_enabled()) {
> 		trace_amd_pstate_epp_perf(cpudata->cpu, cpudata->highest_perf,
> 					  cpudata->epp_cached,
> 					  FIELD_GET(AMD_CPPC_MIN_PERF_MASK, cpudata->cppc_req_cached),
> 					  max_perf, policy->boost_enabled);
> 	}
>
> Since amd_pstate_epp_update_limit() also has the the tracing code.

Yeah; the tracing code gets updated later in the series.
My plan is this commit is a minimal fix, and will go to 6.14, the rest 
will be in 6.15.

> The patch looks good to me otherwise.
>
> Reviewed-by: Gautham R. Shenoy <gautham.shenoy@xxxxxxx>

Thanks!