Messages in this thread | | | From | "Yuan, Perry" <> | Subject | RE: [PATCH v4 4/9] cpufreq: amd_pstate: implement Pstate EPP support for the AMD processors | Date | Fri, 18 Nov 2022 03:54:29 +0000 |
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[AMD Official Use Only - General]
> -----Original Message----- > From: Karny, Wyes <Wyes.Karny@amd.com> > Sent: Thursday, November 17, 2022 10:03 PM > To: Yuan, Perry <Perry.Yuan@amd.com>; rafael.j.wysocki@intel.com; > Limonciello, Mario <Mario.Limonciello@amd.com>; Huang, Ray > <Ray.Huang@amd.com>; viresh.kumar@linaro.org > Cc: Sharma, Deepak <Deepak.Sharma@amd.com>; Fontenot, Nathan > <Nathan.Fontenot@amd.com>; Deucher, Alexander > <Alexander.Deucher@amd.com>; Huang, Shimmer > <Shimmer.Huang@amd.com>; Du, Xiaojian <Xiaojian.Du@amd.com>; Meng, Li > (Jassmine) <Li.Meng@amd.com>; linux-pm@vger.kernel.org; linux- > kernel@vger.kernel.org > Subject: Re: [PATCH v4 4/9] cpufreq: amd_pstate: implement Pstate EPP support > for the AMD processors > > Hi Perry, > > On 11/10/2022 11:28 PM, Perry Yuan wrote: > [snip] > > + > > +static ssize_t store_energy_performance_preference( > > + struct cpufreq_policy *policy, const char *buf, size_t count) { > > + struct amd_cpudata *cpudata = policy->driver_data; > > + char str_preference[21]; > > + ssize_t ret; > > + u32 epp = 0; > > Here `epp` is a unused variable. > [snip] > > @@ -657,6 +1281,20 @@ static int __init amd_pstate_param(char *str) > > if (!str) > > return -EINVAL; > > > > + /* > > + * Disable amd-pstate driver by default for now > > + * append amd-pstate=active or amd-pstate=active > > + * to enable driver loaded > > + */ > > + if (!strcmp(str, "active")) { > > + cppc_load = 1; > > + default_pstate_driver = &amd_pstate_epp_driver; > > + } else if (!strcmp(str, "passive")) { > > + epp_off = 1; > > + cppc_load = 1; > > + default_pstate_driver = &amd_pstate_driver; > > + } > > + > > /* > > * support shared memory type CPPC which has no MSR function. > > * enable amd-pstate on processors with shared memory solution > > In the shared memory support section also `cppc_load` has to be set otherwise > amd_pstate=legacy_cppc will not work. If the patches just got reviewed are accepted, the legacy_cppcc will not be needed any more. I will rebase the EPP patches based on the that.
> > if (!strcmp(str, "legacy_cppc")) { > shared_mem = true; > cppc_load = 1; > }
Previous plan was to add two parameters to kernel command line, passive or active and legacy_cppc for shared memory platform.
> > > -- > Thanks & Regards, > Wyes
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