From: "Gautham R. Shenoy" <gautham.shenoy@amd.com>
To: Mario Limonciello <mario.limonciello@amd.com>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
K Prateek Nayak <kprateek.nayak@amd.com>
Cc: <linux-kernel@vger.kernel.org>, <linux-pm@vger.kernel.org>,
"Gautham R. Shenoy" <gautham.shenoy@amd.com>
Subject: [PATCH 2/9] amd-pstate: Update cppc_req_cached in fast_switch case
Date: Fri, 6 Mar 2026 15:27:46 +0530 [thread overview]
Message-ID: <20260306095753.17155-3-gautham.shenoy@amd.com> (raw)
In-Reply-To: <20260306095753.17155-1-gautham.shenoy@amd.com>
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 updating perf")
Signed-off-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
---
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 *policy, u8 min_perf,
if (fast_switch) {
wrmsrq(MSR_AMD_CPPC_REQ, value);
- return 0;
} else {
int ret = wrmsrq_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
--
2.34.1
next prev parent reply other threads:[~2026-03-06 9:58 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-06 9:57 [PATCH 0/9] amd-pstate: Introduce AMD CPPC Performance Priority Gautham R. Shenoy
2026-03-06 9:57 ` [PATCH 1/9] amd-pstate: Fix memory leak in amd_pstate_epp_cpu_init() Gautham R. Shenoy
2026-03-07 2:29 ` Mario Limonciello (AMD) (kernel.org)
2026-03-06 9:57 ` Gautham R. Shenoy [this message]
2026-03-06 9:57 ` [PATCH 3/9] amd-pstate: Make certain freq_attrs conditionally visible Gautham R. Shenoy
2026-03-06 9:57 ` [PATCH 4/9] x86/cpufeatures: Add AMD CPPC Performance Priority feature Gautham R. Shenoy
2026-03-06 10:45 ` Borislav Petkov
2026-03-06 9:57 ` [PATCH 5/9] amd-pstate: Add support for CPPC_REQ2 and FLOOR_PERF Gautham R. Shenoy
2026-03-06 17:54 ` kernel test robot
2026-03-06 20:22 ` kernel test robot
2026-03-07 0:08 ` kernel test robot
2026-03-06 9:57 ` [PATCH 6/9] amd-pstate: Add sysfs support for floor_freq and floor_count Gautham R. Shenoy
2026-03-06 9:57 ` [PATCH 7/9] amd-pstate: Introduce a tracepoint trace_amd_pstate_cppc_req2() Gautham R. Shenoy
2026-03-06 9:57 ` [PATCH 8/9] Documentation/amd-pstate: List prefcore related sysfs files Gautham R. Shenoy
2026-03-06 9:57 ` [PATCH 9/9] Documentation/amd-pstate: Add documentation for amd_pstate_floor_{freq,count} Gautham R. Shenoy
2026-03-10 3:45 ` K Prateek Nayak
2026-03-11 10:32 ` Gautham R. Shenoy
2026-03-10 3:38 ` [PATCH 0/9] amd-pstate: Introduce AMD CPPC Performance Priority K Prateek Nayak
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