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Shenoy" To: Mario Limonciello , "Rafael J . Wysocki" , Viresh Kumar , K Prateek Nayak CC: , , "Gautham R. Shenoy" Subject: [PATCH v2 2/9] amd-pstate: Update cppc_req_cached in fast_switch case Date: Wed, 11 Mar 2026 19:31:09 +0530 Message-ID: <20260311140116.19604-3-gautham.shenoy@amd.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260311140116.19604-1-gautham.shenoy@amd.com> References: <20260311140116.19604-1-gautham.shenoy@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: satlexmb07.amd.com (10.181.42.216) To satlexmb07.amd.com (10.181.42.216) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BL02EPF00021F6C:EE_|IA1PR12MB7543:EE_ X-MS-Office365-Filtering-Correlation-Id: 7e424499-e16d-46da-ec38-08de7f78215d X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|36860700016|1800799024|376014|22082099003|56012099003|18002099003; X-Microsoft-Antispam-Message-Info: 2eIRjRSk9x3GMfulsxQcUPqZkkxuBOoCseTvjqmS0/qxWnEgrF4g5GLMJXFazvVfjdgUu5ma/VQexK+4ytYG/9pyj+PnicNTOeImnFxiOfoLz4dZRik4rRDbhQTJwb2SeIo0actT/fJVU1tYWC+zVR98cnhO0ZJfq3R3V0WmztalQnfj+YmcPdrJub9AwR1j0QbF4js0SYS1TaEAidHAA8Zx7+cdIKBFEWmrf4ERR+JCZXE3Jeug+2SrxEnWbTTpEB5b+2P9r/5Wguq2dI2GKudg13qGLwk4y6a0A2SY6Tndtzr8YY6bSutqsJPpI/Pkxj5VjjKx6jNjDPsS1ZUYWT7HIxnu21FtnipBsNICADsBqL7zMisd2QaGzN31H5H87lrUPDxECodF5mtbaYg6cfiBEQrEubjoQGFy0D7Nj7oVJkNPmWF89e9co4UfPXKt5ujZVnsIbVIu+niwE3PO99iKuUqzbi+JKXPbsOrSW1R0LCZIkWnWO0oGPolIWXDoze/2hcCoz2hjswePkVrCy0/Bjjo55dmOhjgW7lLbHsLwRCbTM+RjpJ8HbFD6X4a/Ss8uxoIg9ItwU3LTTetiWgyBwyTEFfLQfnxkwOs7MkeFWKKuU+UYazflTxibcxRESjWqMdv/epzIxkMXE5O1Fl3BqRDuetgUeiBJThZN0mNPVwX++N5rnX8vbs33UEhqyAX/0ZWa6iAyQ5cIeimerxkn+rJReJcHhFxyyiLiJv4= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(82310400026)(36860700016)(1800799024)(376014)(22082099003)(56012099003)(18002099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: Mfo+Jf2sQnnoQSJMo0UueGDJYnxfAU/agfMwWUoLEdNxgORiajcdvxNeCV8st0/ZPr4e0sDmzVIZ8MIsILEyncYbohrtKS+rWf2Mvg1wQzTJFGSe1vzX11rzEJbA0ps0/oKRO4TcTA70qZpCW8i+b1Oudy4R+V6Vb2CKR8aT91ZMpsaOlrYhBP3zw9PMhPSOiftOzDDJ5wLTG6FUD+txl/jjwSnwO4fBixzD4JCLr6ObpPharRB2HEPhIu5v/MZ6LXjigWNNIUwQGDpuu2NnKy/XW3+vxMPR69sN3fKCeiAU33BUwYhmni6SybKpNTBVFP1k//phtqrHRMY7rXwOEO/LFB6rVeCEnho2TvdApTmGsyNA3zv6K84w8utJOuI+4AjaqZzcBks3THJkaTm6YU7SyCFkV21Wuef0MFbsYLEf4rX3PQdqeM16hxb0kruc X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 11 Mar 2026 14:11:46.5359 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 7e424499-e16d-46da-ec38-08de7f78215d X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BL02EPF00021F6C.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR12MB7543 Content-Type: text/plain; charset="utf-8" The function msr_update_perf() does not cache the new value that is written to MSR_AMD_CPPC_REQ into the variable cpudata->cppc_req_cached when the update is happening from the fast path. Fix that by caching the value everytime the MSR_AMD_CPPC_REQ gets updated. This issue was discovered by Claude Opus 4.6 with the aid of Chris Mason's AI review-prompts (https://github.com/masoncl/review-prompts/tree/main/kernel). Assisted-by: Claude:claude-opus-4.6 review-prompts/linux Fixes: fff395796917 ("cpufreq/amd-pstate: Always write EPP value when updat= ing perf") Signed-off-by: Gautham R. Shenoy Reviewed-by: Mario Limonciello (AMD) --- drivers/cpufreq/amd-pstate.c | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index d57969c72c9dc..24cdeffbcd40e 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -261,7 +261,6 @@ static int msr_update_perf(struct cpufreq_policy *polic= y, u8 min_perf, =20 if (fast_switch) { wrmsrq(MSR_AMD_CPPC_REQ, value); - return 0; } else { int ret =3D wrmsrq_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value); =20 --=20 2.34.1