Re: [PATCH] drm/amdgpu/ctx: only reset stable pstate if the user changed it (v2)

["Lazar, Lijo" <lijo.lazar@amd.com>]

On 5/10/2022 8:07 PM, Alex Deucher wrote:
> Check if the requested stable pstate matches the current one before
> changing it.  This avoids changing the stable pstate on context
> destroy if the user never changed it in the first place via the
> IOCTL.
> 
> v2: compare the current and requested rather than setting a flag (Lijo)
> 
> Fixes: 8cda7a4f96e435 ("drm/amdgpu/UAPI: add new CTX OP to get/set stable pstates")
> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>

Thanks,
Lijo

> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
> index 5981c7d9bd48..94c3a52df131 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
> @@ -295,6 +295,7 @@ static int amdgpu_ctx_set_stable_pstate(struct amdgpu_ctx *ctx,
>   {
>   	struct amdgpu_device *adev = ctx->adev;
>   	enum amd_dpm_forced_level level;
> +	u32 current_stable_pstate;
>   	int r;
>   
>   	mutex_lock(&adev->pm.stable_pstate_ctx_lock);
> @@ -303,6 +304,10 @@ static int amdgpu_ctx_set_stable_pstate(struct amdgpu_ctx *ctx,
>   		goto done;
>   	}
>   
> +	r = amdgpu_ctx_get_stable_pstate(ctx, &current_stable_pstate);
> +	if (r || (stable_pstate == current_stable_pstate))
> +		goto done;
> +
>   	switch (stable_pstate) {
>   	case AMDGPU_CTX_STABLE_PSTATE_NONE:
>   		level = AMD_DPM_FORCED_LEVEL_AUTO;
>