Messages in this thread Patch in this message | | | Date | Thu, 8 Feb 2024 11:37:29 +0530 | From | "Gautham R. Shenoy" <> | Subject | Re: [PATCH v6 2/6] cpufreq:amd-pstate: fix the nominal freq value set |
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On Thu, Feb 08, 2024 at 11:46:29AM +0800, Perry Yuan wrote: > Address an untested error where the nominal_freq was returned in KHz > instead of the correct MHz units, this oversight led to a wrong > nominal_freq set and resued, it will cause the max frequency of core to > be initialized with a wrong frequency value.
The _CPC object on my Zen2 EPYC server which has CPPC v3, I see : 0x00000190, //LowestFrequency 0x000007D0 //NominalFrequency }) } where 0x7D0 is 2000 Mhz. Thus the value returend by cppc_perf.nominal_freq is in Mhz.
In this patch, we are changing making amd_get_nominal_freq() return 2000 (Mhz) instead of 2000000 (Khz) as it was doing previously.
amd_get_min_freq(), amd_get_max_freq(), amd_get_lowest_nonlinear_perf() -all these functions return the frequency in Khz units.
These functions are used the initialize the value of cpudata->max_freq, cpu_data->min_freq, .... all of which are in Khz units.
In, amd_pstate_set_boost(), we have: if (state) policy->cpuinfo.max_freq = cpudata->max_freq; <---- In Khz else policy->cpuinfo.max_freq = cpudata->nominal_freq; <--- Now in Mhz
Since policy->cpuinfo.max_freq is expected to be in Khz, isn't this patch introducing an error ? Or perhaps this patch series is based on another patchset ?
-- Thanks and Regards gautham.
> > Cc: stable@vger.kernel.org > Fixes: ec437d71db7 ("cpufreq: amd-pstate: Introduce a new AMD P-State driver to support future processors") > Reviewed-by: Mario Limonciello <mario.limonciello@amd.com> > Signed-off-by: Perry Yuan <perry.yuan@amd.com> > --- > drivers/cpufreq/amd-pstate.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c > index 08e112444c27..ac7faa98a450 100644 > --- a/drivers/cpufreq/amd-pstate.c > +++ b/drivers/cpufreq/amd-pstate.c > @@ -640,8 +640,7 @@ static int amd_get_nominal_freq(struct amd_cpudata *cpudata) > if (ret) > return ret; > > - /* Switch to khz */ > - return cppc_perf.nominal_freq * 1000; > + return cppc_perf.nominal_freq; > } > > static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata) > -- > 2.34.1 >
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