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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 2/5] cpufreq/amd-pstate: add kernel command line to override dynamic epp Message-ID: References: <20260106051441.60093-1-superm1@kernel.org> <20260106051441.60093-3-superm1@kernel.org> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260106051441.60093-3-superm1@kernel.org> X-ClientProxiedBy: MA5PR01CA0047.INDPRD01.PROD.OUTLOOK.COM (2603:1096:a01:1d6::19) 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_|LV9PR12MB9806:EE_ X-MS-Office365-Filtering-Correlation-Id: f8315165-2472-4270-8876-08de8bcc8286 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|1800799024|366016|56012099003|18002099003|22082099003; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?eqc3VWSq1wPh8RDNatREjOr8mqDKhl9hXSMCDyX2fPezeBchFYH612HvOqFD?= =?us-ascii?Q?MdQsxBqpW9k/FAFEdT5ErV9Sz/a15+NJUPZyExLv/LfPd5rQoT+EtcPxv27r?= =?us-ascii?Q?lyUgseQQPnWf34MuV5Wmi/iwJSXHysRRRPD8IR+SO46hbj/0/RlVOMK+RsDh?= =?us-ascii?Q?njyyIRnle+PySuCUBADubWkI4AlcGlf+MQKGn4gJrzeCPrV41C5e+2b9EgDw?= =?us-ascii?Q?cYdmQP9qU0BgFbiVcV6zVEjskZwZxtxwIPPR0+VctQvGoGMmZ28WudDjGgER?= =?us-ascii?Q?5s0WXF6jOYtsxGKsn6RVlpRNhIORnGQz0Z5YHy3F2qntg9AuxfbtC72Krg7U?= =?us-ascii?Q?DwEYjVlvTVRrz8bDwB7DigS7WRDj/3wuzlsOREEDnK2S8+bRxvCo78R0GLLm?= =?us-ascii?Q?JZ8jD2+NpcCjUvpU7mrvFgRzDDzUeHj50wEQXt6lw8S4bSW8R1gaQcDqBMbB?= =?us-ascii?Q?zbdR1icwka9B2q67PcNXiYeIkCp2QkkZrWVl5m25DsreLroniRg4x0r22qwU?= =?us-ascii?Q?bJp+SeNWQJmmaZIFFQKD1QrhE6WQs5jhLR3EwzKCAYuok+ij73wSaK54mMIO?= =?us-ascii?Q?HR2mDB9mHgmn2ZWUflWbwowtXqDBjGxR3rDk18pGSPKkV62j+HxZfVCZ85v/?= =?us-ascii?Q?j0bMB6TdPXlOQc4PpfjU4PqSQJsDfBW5oFnZJDa8tmrm6FXuqC9HdQs7C6Cr?= =?us-ascii?Q?d2x4gkjbIL1bB5prIosgOxgpSMldq6eENu9yNsRFJAsHg5pQSx5968pyMeS3?= =?us-ascii?Q?TwRSsHSc5/bH0m7Tsa9b22xNsTtJM9GhpPZfObJbkiVBsuIZXGTf69qa7oj/?= =?us-ascii?Q?OoS02vdmzP3WLZzf/TL7SK6vx+9aEWp6bx/SQRYXrA7MIzEAr5MKpClO6ZL+?= =?us-ascii?Q?dhg1L4Q8K9sC2lXRNrMvsEcUwo2pBdvcBnu2jkGeDfoqDQxzIQDkoH/V2D8C?= =?us-ascii?Q?3xhCU9T1WjjRT0hNcn+k3Q2kYZEsKG1vMIutQCT3DLnRti/iM3fJ4miN0+Vx?= =?us-ascii?Q?nV6JNwE1bVBsRf+BiUj8S/wXkXpyt6fd1Va+vf7NH7jCmlQWqQca68cohstV?= =?us-ascii?Q?H+4k8OxZZyO065fdWBg83YK98nCpvhIDHU2btdBerBvDr45zRpSKU6JaHe6x?= =?us-ascii?Q?nqfCKDHM4Wxt/KmhVnvZEoqs9+3x9KoWjjrzA0XBfaFJ/CAgZSBRvGIGJ8g3?= =?us-ascii?Q?WvC3Vyp3Z87vA688/rL10O8+v+RhLr07Bl/5Ylg7TsozAK0brknbsWvhFKXR?= =?us-ascii?Q?bLXGDXbi+zomed0uXwKxb4Em2Me/9P5KW3Sotyoqy8XbCRbXxfZ/AHeolPF6?= =?us-ascii?Q?L+ADH4RndJo9PY2d9kQhDSx2jAM6uniPuEiGN5PF5nWJGxugvux297HdTv3Z?= =?us-ascii?Q?eeMf9NMd4K/hKdhlA6o+XBqXDSmbpOFtcBc35vaF+/k5XxUJcU1I1sB8qMeP?= =?us-ascii?Q?zsU6gtBqth84HvAsGeD1Xt9K437L9yDAetdENsbqIgHeURboBy/h540HnSJm?= =?us-ascii?Q?0ff7Rb3DXlfxk7H2KD0xNUtj+KKMvb7Fdw+HevX1CX+KrIxQGLaRP33eWd8v?= =?us-ascii?Q?3Yo/8XzSFsnIgqWBHL4GNS9s8ErMMFDEHSTH9aHO9ef7/slCunTtMWNTLhKK?= =?us-ascii?Q?2z/5FJPeEjtNAYVKyEKtaRaC5GCUOyjiuk0ZT1nkUON3N5A5zxQ+3cFlA7TU?= =?us-ascii?Q?OorJMFi6KTAVy/tWlK9YZWoCS9JVoi7iqAAOyRiDkiKw6XLNTVx/XRhkTwWi?= =?us-ascii?Q?T1SYIcZXAw=3D=3D?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: f8315165-2472-4270-8876-08de8bcc8286 X-MS-Exchange-CrossTenant-AuthSource: DS7PR12MB8252.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Mar 2026 06:46:01.4089 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: Af1G4lHqixF0b5B8kHvC99gX5F6GsVWgMriP0ACmnJ5OokDpFyJ9LgEVaCr4RLZYIfnZPSzyb9qP1cDvbB1tiA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV9PR12MB9806 On Mon, Jan 05, 2026 at 11:14:38PM -0600, Mario Limonciello wrote: > From: Mario Limonciello > > Add `amd_dynamic_epp=enable` and `amd_dynamic_epp=disable` to override > the kernel configuration option `CONFIG_X86_AMD_PSTATE_DYNAMIC_EPP` > locally. > > Signed-off-by: Mario Limonciello > --- > Documentation/admin-guide/kernel-parameters.txt | 7 +++++++ > Documentation/admin-guide/pm/amd-pstate.rst | 7 +++++++ > drivers/cpufreq/amd-pstate.c | 11 +++++++++++ > 3 files changed, 25 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index a8d0afde7f85a..d7d547bbda430 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -490,6 +490,13 @@ Kernel parameters > disable > Disable amd-pstate preferred core. > > + amd_dynamic_epp= > + [X86] > + disable > + Disable amd-pstate dynamic EPP. > + enable > + Enable amd-pstate dynamic EPP. > + > amijoy.map= [HW,JOY] Amiga joystick support > Map of devices attached to JOY0DAT and JOY1DAT > Format: , > diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst > index 5aa9fb77a078c..df4607b6a5f62 100644 > --- a/Documentation/admin-guide/pm/amd-pstate.rst > +++ b/Documentation/admin-guide/pm/amd-pstate.rst > @@ -438,6 +438,13 @@ For systems that support ``amd-pstate`` preferred core, the core rankings will > always be advertised by the platform. But OS can choose to ignore that via the > kernel parameter ``amd_prefcore=disable``. > > +``amd_dynamic_epp`` > + > +When AMD pstate is in auto mode, dynamic EPP will control whether the kernel > +autonomously changes the EPP mode. The default is configured by > +``CONFIG_X86_AMD_PSTATE_DYNAMIC_EPP`` but can be explicitly enabled with > +``amd_pstate_epp=enable`` or disabled with ``amd_pstate_epp=disable``. Do you mean amd_dynamic_epp instead of amd_pstate_epp here ? The code and kernel-parameters.txt both use amd_dynamic_epp, not amd_pstate_epp: drivers/cpufreq/amd-pstate.c: early_param("amd_dynamic_epp", amd_dynamic_epp_param); Documentation/admin-guide/kernel-parameters.txt: amd_dynamic_epp= > + > User Space Interface in ``sysfs`` - General > =========================================== > > diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c > index 26a8552581c57..7dd50b5825d78 100644 > --- a/drivers/cpufreq/amd-pstate.c > +++ b/drivers/cpufreq/amd-pstate.c > @@ -1992,8 +1992,19 @@ static int __init amd_prefcore_param(char *str) > return 0; > } > > +static int __init amd_dynamic_epp_param(char *str) > +{ > + if (!strcmp(str, "disable")) > + dynamic_epp = false; > + if (!strcmp(str, "enable")) > + dynamic_epp = true; > + > + return 0; > +} > + > early_param("amd_pstate", amd_pstate_param); > early_param("amd_prefcore", amd_prefcore_param); > +early_param("amd_dynamic_epp", amd_dynamic_epp_param); > > MODULE_AUTHOR("Huang Rui "); > MODULE_DESCRIPTION("AMD Processor P-state Frequency Driver"); > > -- > 2.43.0 > -- Thanks and Regards gautham.