Re: [Intel-gfx] [PATCH] drm/i915/display: Allow users to disable PSR2

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, Feb 23, 2022 at 11:41:03AM -0800, José Roberto de Souza wrote:
> Some users are suffering with PSR2 issues that are under debug or
> issues that were root caused to panel firmware, to make life of those
> users easier here adding a option to disable PSR1 with kernel
> parameter.
> 
> Using the same enable_psr that is current used to turn PSR1 and PSR2
> off or on and adding a new value to only disable PSR2.
> The previous valid values did not had their behavior changed.
> 
> Link: https://gitlab.freedesktop.org/drm/intel/-/issues/4951
> Cc: Jouni Högander <jouni.hogander@intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_psr.c | 4 ++++
>  drivers/gpu/drm/i915/i915_params.c       | 2 +-
>  2 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> index 2e0b092f4b6be..fc6b684bb7bec 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -100,11 +100,15 @@ static bool psr_global_enabled(struct intel_dp *intel_dp)
>  
>  static bool psr2_global_enabled(struct intel_dp *intel_dp)
>  {
> +	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> +
>  	switch (intel_dp->psr.debug & I915_PSR_DEBUG_MODE_MASK) {
>  	case I915_PSR_DEBUG_DISABLE:
>  	case I915_PSR_DEBUG_FORCE_PSR1:
>  		return false;
>  	default:
> +		if (i915->params.enable_psr == 2)
> +			return false;
>  		return true;
>  	}
>  }
> diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
> index eea355c2fc28a..a9b97e6eb3df0 100644
> --- a/drivers/gpu/drm/i915/i915_params.c
> +++ b/drivers/gpu/drm/i915/i915_params.c
> @@ -94,7 +94,7 @@ i915_param_named_unsafe(enable_hangcheck, bool, 0400,
>  
>  i915_param_named_unsafe(enable_psr, int, 0400,
>  	"Enable PSR "
> -	"(0=disabled, 1=enabled) "
> +	"(0=disabled, 1=enable up to PSR2 if supported, 2=enable up to PSR1) "

That seems very unintuitive. I would just make it 1==PSR1 and 2==PSR2.

>  	"Default: -1 (use per-chip default)");
>  
>  i915_param_named(psr_safest_params, bool, 0400,
> -- 
> 2.35.1

-- 
Ville Syrjälä
Intel