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Shenoy" To: Mario Limonciello Cc: Perry Yuan , "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , "open list:CPU FREQUENCY SCALING FRAMEWORK" , Mario Limonciello Subject: Re: [PATCH v5 4/5] cpufreq/amd-pstate: Add support for raw EPP writes Message-ID: References: <20260106051441.60093-1-superm1@kernel.org> <20260106051441.60093-5-superm1@kernel.org> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260106051441.60093-5-superm1@kernel.org> X-ClientProxiedBy: MA0P287CA0012.INDP287.PROD.OUTLOOK.COM (2603:1096:a01:d9::11) To DS7PR12MB8252.namprd12.prod.outlook.com (2603:10b6:8:ee::7) Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS7PR12MB8252:EE_|CY3PR12MB9553:EE_ X-MS-Office365-Filtering-Correlation-Id: fcbe20a8-cc43-4104-8243-08de8bdcb0ba X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|1800799024|366016|22082099003|56012099003|18002099003; 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If the last value written was an integer then > an integer will be returned. If the last value written was a string > then a string will be returned. Support for raw EPP values was present in the previous patch itself. It appears that some hunks from the previous patch belong here. > > Signed-off-by: Mario Limonciello > --- > Documentation/admin-guide/pm/amd-pstate.rst | 16 +++++++++++----- > drivers/cpufreq/amd-pstate.c | 11 +++++++++-- > drivers/cpufreq/amd-pstate.h | 1 + > 3 files changed, 21 insertions(+), 7 deletions(-) > > diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst > index a6745f2358e61..674e76ff9293e 100644 > --- a/Documentation/admin-guide/pm/amd-pstate.rst > +++ b/Documentation/admin-guide/pm/amd-pstate.rst > @@ -280,16 +280,22 @@ A list of all the supported EPP preferences that could be used for > These profiles represent different hints that are provided > to the low-level firmware about the user's desired energy vs efficiency > tradeoff. ``default`` represents the epp value is set by platform > -firmware. This attribute is read-only. > +firmware. ``custom`` designates that integer values 0-255 may be written > +as well. This attribute is read-only. > > ``energy_performance_preference`` > > The current energy performance preference can be read from this attribute. > and user can change current preference according to energy or performance needs > -Please get all support profiles list from > -``energy_performance_available_preferences`` attribute, all the profiles are > -integer values defined between 0 to 255 when EPP feature is enabled by platform > -firmware, but if the dynamic EPP feature is enabled, driver will block writes. > +Coarse named profiles are available in the attribute > +``energy_performance_available_preferences``. > +Users can also write individual integer values between 0 to 255. > +When EPP feature is enabled by platform firmware but if the dynamic EPP feature is > +enabled, driver will ignore the written value. Lower epp values shift the bias > +towards improved performance while a higher epp value shifts the bias towards > +power-savings. The exact impact can change from one platform to the other. > +If a valid integer was last written, then a number will be returned on future reads. > +If a valid string was last written then a string will be returned on future reads. > This attribute is read-write. > > ``boost`` > diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c > index e1ccbbdd56d42..14347baf3cefb 100644 > --- a/drivers/cpufreq/amd-pstate.c > +++ b/drivers/cpufreq/amd-pstate.c > @@ -1333,6 +1333,7 @@ ssize_t store_energy_performance_preference(struct cpufreq_policy *policy, > { > struct amd_cpudata *cpudata = policy->driver_data; > ssize_t ret; > + bool raw_epp = FALSE; s/FALSE/false ? false is already defined in and rest of the file uses it. > u8 epp; > > if (cpudata->dynamic_epp) { > @@ -1345,6 +1346,7 @@ ssize_t store_energy_performance_preference(struct cpufreq_policy *policy, > * matches an index in the energy_perf_strings array > */ > ret = kstrtou8(buf, 0, &epp); > + raw_epp = !ret; > if (ret) { > ret = sysfs_match_string(energy_perf_strings, buf); > if (ret < 0 || ret == EPP_INDEX_CUSTOM) > @@ -1364,7 +1366,9 @@ ssize_t store_energy_performance_preference(struct cpufreq_policy *policy, > if (ret) > return ret; > > - return ret ? ret : count; > + cpudata->raw_epp = raw_epp; > + > + return count; > } > EXPORT_SYMBOL_GPL(store_energy_performance_preference); > > @@ -1375,6 +1379,9 @@ ssize_t show_energy_performance_preference(struct cpufreq_policy *policy, char * > > epp = FIELD_GET(AMD_CPPC_EPP_PERF_MASK, cpudata->cppc_req_cached); > > + if (cpudata->raw_epp) > + return sysfs_emit(buf, "%u\n", epp); > + > switch (epp) { > case AMD_CPPC_EPP_PERFORMANCE: > preference = EPP_INDEX_PERFORMANCE; > @@ -1389,7 +1396,7 @@ ssize_t show_energy_performance_preference(struct cpufreq_policy *policy, char * > preference = EPP_INDEX_POWERSAVE; > break; > default: > - return sysfs_emit(buf, "%u\n", epp); > + return -EINVAL; > } > > return sysfs_emit(buf, "%s\n", energy_perf_strings[preference]); > diff --git a/drivers/cpufreq/amd-pstate.h b/drivers/cpufreq/amd-pstate.h > index 9839c7c6558f4..38b575b8ad959 100644 > --- a/drivers/cpufreq/amd-pstate.h > +++ b/drivers/cpufreq/amd-pstate.h > @@ -110,6 +110,7 @@ struct amd_cpudata { > u8 epp_default_ac; > u8 epp_default_dc; > bool dynamic_epp; > + bool raw_epp; > struct notifier_block power_nb; Looks good otherwise. -- Thanks and Regards gautham.