Re: [PATCH] cpufreq: amd-pstate: Allow users to write 'default' EPP string

[Gautham R.Shenoy <gautham.shenoy@amd.com>]

Mario Limonciello <mario.limonciello@amd.com> writes:

> The EPP string for 'default' represents what the firmware had configured
> as the default EPP value but once a user changes EPP to another string
> they can't reset it back to 'default'.
>
> Cache the firmware EPP value and allow the user to write 'default' using
> this value.
>
> Reported-by: Artem S. Tashkinov <aros@gmx.com>
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217931#c61
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>

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

> ---
>  drivers/cpufreq/amd-pstate.c | 8 +++-----
>  drivers/cpufreq/amd-pstate.h | 1 +
>  2 files changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index fda8f86c90e0..5bdcdd3ea163 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -282,10 +282,8 @@ static int amd_pstate_set_energy_pref_index(struct amd_cpudata *cpudata,
>  	int epp = -EINVAL;
>  	int ret;
>  
> -	if (!pref_index) {
> -		pr_debug("EPP pref_index is invalid\n");
> -		return -EINVAL;
> -	}
> +	if (!pref_index)
> +		epp = cpudata->epp_default;
>  
>  	if (epp == -EINVAL)
>  		epp = epp_values[pref_index];
> @@ -1441,7 +1439,7 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
>  
>  	policy->driver_data = cpudata;
>  
> -	cpudata->epp_cached = amd_pstate_get_epp(cpudata, 0);
> +	cpudata->epp_cached = cpudata->epp_default = amd_pstate_get_epp(cpudata, 0);
>  
>  	policy->min = policy->cpuinfo.min_freq;
>  	policy->max = policy->cpuinfo.max_freq;
> diff --git a/drivers/cpufreq/amd-pstate.h b/drivers/cpufreq/amd-pstate.h
> index e6a28e7f4dbf..f80b33fa5d43 100644
> --- a/drivers/cpufreq/amd-pstate.h
> +++ b/drivers/cpufreq/amd-pstate.h
> @@ -99,6 +99,7 @@ struct amd_cpudata {
>  	u32	policy;
>  	u64	cppc_cap1_cached;
>  	bool	suspended;
> +	s16	epp_default;
>  };
>  
>  #endif /* _LINUX_AMD_PSTATE_H */
> -- 
> 2.43.0