linux-kernel - Re: [PATCH 01/14] cpufreq/amd-pstate: Show a warning when a CPU fails to setup

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Message-ID: <c7b4e115-91b6-4964-ad4a-58e8924997a3@amd.com>
Date: Mon, 10 Feb 2025 17:29:24 +0530
From: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
To: Mario Limonciello <superm1@...nel.org>,
 "Gautham R . Shenoy" <gautham.shenoy@....com>,
 Perry Yuan <perry.yuan@....com>
Cc: "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
 <linux-kernel@...r.kernel.org>,
 "open list:CPU FREQUENCY SCALING FRAMEWORK" <linux-pm@...r.kernel.org>,
 Mario Limonciello <mario.limonciello@....com>
Subject: Re: [PATCH 01/14] cpufreq/amd-pstate: Show a warning when a CPU fails
 to setup

On 2/7/2025 3:26 AM, Mario Limonciello wrote:
> From: Mario Limonciello <mario.limonciello@....com>
> 
> I came across a system that MSR_AMD_CPPC_CAP1 for some CPUs isn't
> populated.  This is an unexpected behavior that is most likely a
> BIOS bug. In the event it happens I'd like users to report bugs
> to properly root cause and get this fixed.

I'm okay with this patch, but I see a similar pr_debug in caller cpufreq_online(),
so not sure if this is strictly necessary.

1402                 /*
1403                  * Call driver. From then on the cpufreq must be able
1404                  * to accept all calls to ->verify and ->setpolicy for this CPU.
1405                  */
1406                 ret = cpufreq_driver->init(policy);
1407                 if (ret) {
1408                         pr_debug("%s: %d: initialization failed\n", __func__,
1409                                  __LINE__);
1410                         goto out_free_policy;
1411                  

Thanks,
Dhananjay

> 
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
>  drivers/cpufreq/amd-pstate.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index f425fb7ec77d7..573643654e8d6 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -1034,6 +1034,7 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>  free_cpudata2:
>  	freq_qos_remove_request(&cpudata->req[0]);
>  free_cpudata1:
> +	pr_warn("Failed to initialize CPU %d: %d\n", policy->cpu, ret);
>  	kfree(cpudata);
>  	return ret;
>  }
> @@ -1527,6 +1528,7 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
>  	return 0;
>  
>  free_cpudata1:
> +	pr_warn("Failed to initialize CPU %d: %d\n", policy->cpu, ret);
>  	kfree(cpudata);
>  	return ret;
>  }