linux-kernel - Re: [PATCH 3/3] cpufreq: amd-pstate: Add a module device table

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Message-ID: <YkBmQCWnM3T53fEr@amd.com>
Date:   Sun, 27 Mar 2022 21:27:28 +0800
From:   Huang Rui <ray.huang@....com>
To:     "Limonciello, Mario" <Mario.Limonciello@....com>
Cc:     "Rafael J . Wysocki" <rafael@...nel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        "open list:AMD PSTATE DRIVER" <linux-pm@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] cpufreq: amd-pstate: Add a module device table

On Fri, Mar 25, 2022 at 01:42:28PM +0800, Limonciello, Mario wrote:
> `amd-pstate` currently only loads automatically if compiled into the
> kernel.  To improve the usability, add a module device table that
> will load when AMD CPUs that support CPPC are detected.
> 

There is one AMD semi-custom processor which has the CPPC feature flag, but
the SBIOS doesn't support _CPC objects.

Thanks,
Ray

> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
>  drivers/cpufreq/amd-pstate.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 31a04e818195..44490292fa72 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -644,6 +644,12 @@ static void __exit amd_pstate_exit(void)
>  	amd_pstate_enable(false);
>  }
>  
> +static const struct x86_cpu_id __maybe_unused amd_pstate_ids[] = {
> +	X86_MATCH_VENDOR_FEATURE(AMD, X86_FEATURE_CPPC, NULL),
> +	{}
> +};
> +MODULE_DEVICE_TABLE(x86cpu, amd_pstate_ids);
> +
>  module_init(amd_pstate_init);
>  module_exit(amd_pstate_exit);
>  
> -- 
> 2.34.1
>