linux-kernel - Re: [PATCH v9 5/8] cpufreq: amd-pstate: Bail out if min/max/nominal

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Message-ID: <ZflhlzoGmWCkZjnn@BLR-5CG11610CF.amd.com>
Date: Tue, 19 Mar 2024 15:27:43 +0530
From: "Gautham R. Shenoy" <gautham.shenoy@....com>
To: Perry Yuan <perry.yuan@....com>
Cc: rafael.j.wysocki@...el.com, Mario.Limonciello@....com,
	viresh.kumar@...aro.org, Borislav.Petkov@....com, Ray.Huang@....com,
	Alexander.Deucher@....com, Xinmei.Huang@....com,
	oleksandr@...alenko.name, Xiaojian.Du@....com, Li.Meng@....com,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v9 5/8] cpufreq: amd-pstate: Bail out if
 min/max/nominal_freq is 0

Hello Perry,

On Tue, Mar 19, 2024 at 04:28:40PM +0800, Perry Yuan wrote:
> The amd-pstate driver cannot work when the min_freq, nominal_freq or
> the max_freq is zero. When this happens it is prudent to error out
> early on rather than waiting failing at the time of the governor
> initialization.
>

This patch looks good to me.

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

> Signed-off-by: Perry Yuan <perry.yuan@....com>
> ---
>  drivers/cpufreq/amd-pstate.c | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 132330b4942f..6708c436e1a2 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -839,9 +839,11 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>  	nominal_freq = READ_ONCE(cpudata->nominal_freq);
>  	lowest_nonlinear_freq = READ_ONCE(cpudata->lowest_nonlinear_freq);
>  
> -	if (min_freq < 0 || max_freq < 0 || min_freq > max_freq) {
> -		dev_err(dev, "min_freq(%d) or max_freq(%d) value is incorrect\n",
> -			min_freq, max_freq);
> +	if (min_freq <= 0 || max_freq <= 0 ||
> +	    nominal_freq <= 0 || min_freq > max_freq) {
> +		dev_err(dev,
> +			"min_freq(%d) or max_freq(%d) or nominal_freq (%d) value is incorrect\n",
> +			min_freq, max_freq, nominal_freq);
>  		ret = -EINVAL;
>  		goto free_cpudata1;
>  	}
> @@ -1299,9 +1301,11 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
>  	max_freq = READ_ONCE(cpudata->max_freq);
>  	nominal_freq = READ_ONCE(cpudata->nominal_freq);
>  	lowest_nonlinear_freq = READ_ONCE(cpudata->lowest_nonlinear_freq);
> -	if (min_freq < 0 || max_freq < 0 || min_freq > max_freq) {
> -		dev_err(dev, "min_freq(%d) or max_freq(%d) value is incorrect\n",
> -				min_freq, max_freq);
> +	if (min_freq <= 0 || max_freq <= 0 ||
> +	    nominal_freq <= 0 || min_freq > max_freq) {
> +		dev_err(dev,
> +			"min_freq(%d) or max_freq(%d) or nominal_freq(%d) value is incorrect\n",
> +			min_freq, max_freq, nominal_freq);
>  		ret = -EINVAL;
>  		goto free_cpudata1;
>  	}
> -- 
> 2.34.1
>

--
Thanks and Regards
gautham.