RE: [PATCH] cpufreq/amd-pstate: Fix the return value of amd_pstate_fast_switch()

[Yuan, Perry]

[AMD Official Use Only - General]

> -----Original Message-----
> From: Shenoy, Gautham Ranjal <gautham.shenoy@xxxxxxx>
> Sent: Thursday, November 23, 2023 4:28 PM
> To: Karny, Wyes <Wyes.Karny@xxxxxxx>; Huang, Ray
> <Ray.Huang@xxxxxxx>; Limonciello, Mario <Mario.Limonciello@xxxxxxx>;
> Yuan, Perry <Perry.Yuan@xxxxxxx>; Rafael J . Wysocki <rafael@xxxxxxxxxx>;
> Viresh Kumar <viresh.kumar@xxxxxxxxxx>
> Cc: linux-pm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Shenoy, Gautham
> Ranjal <gautham.shenoy@xxxxxxx>
> Subject: [PATCH] cpufreq/amd-pstate: Fix the return value of
> amd_pstate_fast_switch()
>
> cpufreq_driver->fast_switch() callback expects a frequency as a return value.
> amd_pstate_fast_switch() was returning the return value of
> amd_pstate_update_freq(), which only indicates a success or failure.
>
> Fix this by making amd_pstate_fast_switch() return the target_freq when the
> call to amd_pstate_update_freq() is successful, and return the current
> frequency from policy->cur when the call to
> amd_pstate_update_freq() is unsuccessful.
>
> Fixes: 4badf2eb1e98 ("cpufreq: amd-pstate: Add ->fast_switch() callback")
> Signed-off-by: Gautham R. Shenoy <gautham.shenoy@xxxxxxx>
> ---
>  drivers/cpufreq/amd-pstate.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 9a1e194d5cf8..300f81d36291 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -518,7 +518,9 @@ static int amd_pstate_target(struct cpufreq_policy
> *policy,  static unsigned int amd_pstate_fast_switch(struct cpufreq_policy
> *policy,
>                                 unsigned int target_freq)
>  {
> -     return amd_pstate_update_freq(policy, target_freq, true);
> +     if (!amd_pstate_update_freq(policy, target_freq, true))
> +             return target_freq;
> +     return policy->cur;
>  }
>
>  static void amd_pstate_adjust_perf(unsigned int cpu,
> --
> 2.25.1

LGTM
Thank you for the fix.

Reviewed-by: Perry Yuan <perry.yuan@xxxxxxx>