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Message-Id: <20240730140111.4491-1-00107082@163.com>
Date: Tue, 30 Jul 2024 22:01:11 +0800
From: David Wang <00107082@....com>
To: perry.yuan@....com
Cc: Alexander.Deucher@....com,
Li.Meng@....com,
Mario.Limonciello@....com,
Xiaojian.Du@....com,
Xinmei.Huang@....com,
gautham.shenoy@....com,
linux-kernel@...r.kernel.org,
linux-pm@...r.kernel.org,
rafael.j.wysocki@...el.com,
viresh.kumar@...aro.org,
00107082@....com
Subject: [Regression] 6.11.0-rc1: AMD CPU boot with error when CPPC feature disabled by BIOS
Hi,
I notice some kernel warning and errors when I update to 6.11.0-rc1:
kernel: [ 1.022739] amd_pstate: The CPPC feature is supported but currently disabled by the BIOS.
kernel: [ 1.022739] Please enable it if your BIOS has the CPPC option.
kernel: [ 1.098054] amd_pstate: min_freq(0) or max_freq(0) or nominal_freq(0) value is incorrect
kernel: [ 1.110058] amd_pstate: min_freq(0) or max_freq(0) or nominal_freq(0) value is incorrect
kernel: [ 1.122057] amd_pstate: min_freq(0) or max_freq(0) or nominal_freq(0) value is incorrect
kernel: [ 1.134062] amd_pstate: min_freq(0) or max_freq(0) or nominal_freq(0) value is incorrect
kernel: [ 1.134641] amd_pstate: min_freq(0) or max_freq(0) or nominal_freq(0) value is incorrect
kernel: [ 1.135128] amd_pstate: min_freq(0) or max_freq(0) or nominal_freq(0) value is incorrect
kernel: [ 1.135693] amd_pstate: min_freq(0) or max_freq(0) or nominal_freq(0) value is incorrect
kernel: [ 1.136371] amd_pstate: min_freq(0) or max_freq(0) or nominal_freq(0) value is incorrect
kernel: [ 1.136390] amd_pstate: failed to register with return -19
kernel: [ 1.138410] ledtrig-cpu: registered to indicate activity on CPUs
Those warning message was introduced by commit:
bff7d13c190ad98cf4f877189b022c75df4cb383 ("cpufreq: amd-pstate: add debug message while CPPC is supported and disabled by SBIOS)
, which make sense.
Those error message was introduced by commit:
8f8b42c1fcc939a73b547b172a9ffcb65ef4bf47 ("cpufreq: amd-pstate: optimize the initial frequency values verification")
, when CPPC is disabled by BIOS, this error message does not make sense, and the error return-code would abort the driver registeration,
but this behavior could be handled earlier when detecting CPPC feature.
I feel following changes would make a clean fix: do not register amd_pstate driver when CPPC disabled by BIOS.
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 68c616b572f2..b06faea58fd4 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -1837,8 +1837,6 @@ static bool amd_cppc_supported(void)
* If the CPPC feature is disabled in the BIOS for processors that support MSR-based CPPC,
* the AMD Pstate driver may not function correctly.
* Check the CPPC flag and display a warning message if the platform supports CPPC.
- * Note: below checking code will not abort the driver registeration process because of
- * the code is added for debugging purposes.
*/
if (!cpu_feature_enabled(X86_FEATURE_CPPC)) {
if (cpu_feature_enabled(X86_FEATURE_ZEN1) || cpu_feature_enabled(X86_FEATURE_ZEN2)) {
@@ -1856,6 +1854,7 @@ static bool amd_cppc_supported(void)
if (warn)
pr_warn_once("The CPPC feature is supported but currently disabled by the BIOS.\n"
"Please enable it if your BIOS has the CPPC option.\n");
+ return false;
return true;
}
Thanks
David
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