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Date: Thu, 8 Feb 2024 12:16:46 +0530
From: "Gautham R. Shenoy" <gautham.shenoy@amd.com>
To: Perry Yuan <perry.yuan@amd.com>
Cc: rafael.j.wysocki@intel.com, Mario.Limonciello@amd.com,
	viresh.kumar@linaro.org, Ray.Huang@amd.com, Borislav.Petkov@amd.com,
	Alexander.Deucher@amd.com, Xinmei.Huang@amd.com,
	Xiaojian.Du@amd.com, Li.Meng@amd.com, linux-pm@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 5/6] cppc_acpi: print error message if CPPC is
 unsupported
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On Thu, Feb 08, 2024 at 11:46:32AM +0800, Perry Yuan wrote:
> to be more clear what is wrong with CPPC when pstate driver failed to
> load which has dependency on the CPPC capabilities.
> 
> Add one more debug message to notify user if CPPC is not supported by
> the CPU, then it will be easy to find out what need to fix for pstate
> driver loading issue.
> 
> [    0.477523] amd_pstate: the _CPC object is not present in SBIOS or ACPI disabled
> 
> Above message is not clear enough to verify whether CPPC is not supported.

Looks good to me.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>

> 
> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
> Signed-off-by: Perry Yuan <perry.yuan@amd.com>
> ---
>  drivers/acpi/cppc_acpi.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> index a50e70abdf19..e23a84f4a50a 100644
> --- a/drivers/acpi/cppc_acpi.c
> +++ b/drivers/acpi/cppc_acpi.c
> @@ -679,8 +679,10 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
>  
>  	if (!osc_sb_cppc2_support_acked) {
>  		pr_debug("CPPC v2 _OSC not acked\n");
> -		if (!cpc_supported_by_cpu())
> +		if (!cpc_supported_by_cpu()) {
> +			pr_debug("CPPC is not supported by the CPU\n");
>  			return -ENODEV;
> +		}
>  	}
>  
>  	/* Parse the ACPI _CPC table for this CPU. */
> -- 
> 2.34.1
>