[Intel-gfx] [PATCH 1/2] drm/i915: Add generic constraint checker when determining DP MST DSC bpp

[Jani Nikula]

On Thu, 02 Feb 2023, Stanislav Lisovskiy <stanislav.lisovskiy at intel.com> wrote:
> There are might be multiple contraints which we need to check while determining
> if we can use desired compressed bpp, so might be good idea to add a special
> helper, so that we don't overcomplicate the main bpp calculation function.

It is, but I don't see the value in adding an empty function like this.

>
> Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp_mst.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index 8b0e4defa3f1..e3e7c305fece 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -45,6 +45,13 @@
>  #include "intel_hotplug.h"
>  #include "skl_scaler.h"
>  
> +static int intel_dp_mst_check_constraints(struct drm_i915_private *i915, int bpp,
> +					  const struct drm_display_mode *adjusted_mode,
> +					  struct intel_crtc_state *crtc_state)
> +{
> +	return 0;
> +}
> +
>  static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
>  						struct intel_crtc_state *crtc_state,
>  						int max_bpp,
> @@ -87,6 +94,10 @@ static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
>  
>  		drm_dbg_kms(&i915->drm, "Trying bpp %d\n", bpp);
>  
> +		ret = intel_dp_mst_check_constraints(i915, bpp, adjusted_mode, crtc_state);
> +		if (ret)
> +			continue;
> +
>  		slots = drm_dp_atomic_find_time_slots(state, &intel_dp->mst_mgr,
>  						      connector->port,
>  						      crtc_state->pbn);
> @@ -104,8 +115,8 @@ static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
>  		}
>  	}
>  
> -	/* Despite slots are non-zero, we still failed the atomic check */
> -	if (ret && slots >= 0)
> +	/* We failed to find a proper bpp/timeslots, return error */
> +	if (ret)
>  		slots = ret;
>  
>  	if (slots < 0) {

-- 
Jani Nikula, Intel Open Source Graphics Center