Re: [PATCH] drm/i915/vdsc: Use the DSC config tables for DSI panels

[Jani Nikula <jani.nikula@linux.intel.com>]

On Thu, 27 Feb 2025, Suraj Kandpal <suraj.kandpal@intel.com> wrote:
> Some DSI panel vendors end up hardcoding PPS params because of which
> it does not listen to the params sent from the source. We use the
> default config tables for DSI panels when using DSC 1.1 rather than
> calculate our own rc parameters.
>
> Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13719
> Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
> ---
>  drivers/gpu/drm/i915/display/icl_dsi.c    | 2 +-
>  drivers/gpu/drm/i915/display/intel_dp.c   | 3 ++-
>  drivers/gpu/drm/i915/display/intel_vdsc.c | 7 +++++--
>  drivers/gpu/drm/i915/display/intel_vdsc.h | 3 ++-
>  4 files changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c b/drivers/gpu/drm/i915/display/icl_dsi.c
> index 5d3d54922d62..9022692c86ef 100644
> --- a/drivers/gpu/drm/i915/display/icl_dsi.c
> +++ b/drivers/gpu/drm/i915/display/icl_dsi.c
> @@ -1607,7 +1607,7 @@ static int gen11_dsi_dsc_compute_config(struct intel_encoder *encoder,
>  
>  	vdsc_cfg->pic_height = crtc_state->hw.adjusted_mode.crtc_vdisplay;
>  
> -	ret = intel_dsc_compute_params(crtc_state);
> +	ret = intel_dsc_compute_params(crtc_state, encoder);
>  	if (ret)
>  		return ret;
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 03ca2e02ab02..14a8cdcd1762 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -1856,6 +1856,7 @@ static int intel_dp_dsc_compute_params(const struct intel_connector *connector,
>  {
>  	struct intel_display *display = to_intel_display(connector);
>  	struct drm_dsc_config *vdsc_cfg = &crtc_state->dsc.config;
> +	struct intel_encoder *encoder = connector->encoder;
>  	int ret;
>  
>  	/*
> @@ -1869,7 +1870,7 @@ static int intel_dp_dsc_compute_params(const struct intel_connector *connector,
>  
>  	vdsc_cfg->slice_height = intel_dp_get_slice_height(vdsc_cfg->pic_height);
>  
> -	ret = intel_dsc_compute_params(crtc_state);
> +	ret = intel_dsc_compute_params(crtc_state, encoder);
>  	if (ret)
>  		return ret;
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.c b/drivers/gpu/drm/i915/display/intel_vdsc.c
> index 6e7151346382..fd8602c1fa7d 100644
> --- a/drivers/gpu/drm/i915/display/intel_vdsc.c
> +++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
> @@ -260,7 +260,8 @@ static int intel_dsc_slice_dimensions_valid(struct intel_crtc_state *pipe_config
>  	return 0;
>  }
>  
> -int intel_dsc_compute_params(struct intel_crtc_state *pipe_config)
> +int intel_dsc_compute_params(struct intel_crtc_state *pipe_config,
> +			     struct intel_encoder *encoder)
>  {
>  	struct intel_crtc *crtc = to_intel_crtc(pipe_config->uapi.crtc);
>  	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> @@ -320,7 +321,9 @@ int intel_dsc_compute_params(struct intel_crtc_state *pipe_config)
>  	 * upto uncompressed bpp-1, hence add calculations for all the rc
>  	 * parameters
>  	 */
> -	if (DISPLAY_VER(dev_priv) >= 13) {
> +	if (DISPLAY_VER(dev_priv) >= 13 &&
> +	    (vdsc_cfg->dsc_version_minor != 1 ||
> +	     encoder->type != INTEL_OUTPUT_DSI)) {

What's wrong with this:

	intel_crtc_has_type(pipe_config, INTEL_OUTPUT_DSI)

Saves the trouble of passing the encoder around.

BR,
Jani.


>  		calculate_rc_params(vdsc_cfg);
>  	} else {
>  		if ((compressed_bpp == 8 ||
> diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.h b/drivers/gpu/drm/i915/display/intel_vdsc.h
> index 9e2812f99dd7..50681fb3c129 100644
> --- a/drivers/gpu/drm/i915/display/intel_vdsc.h
> +++ b/drivers/gpu/drm/i915/display/intel_vdsc.h
> @@ -19,7 +19,8 @@ bool intel_dsc_source_support(const struct intel_crtc_state *crtc_state);
>  void intel_uncompressed_joiner_enable(const struct intel_crtc_state *crtc_state);
>  void intel_dsc_enable(const struct intel_crtc_state *crtc_state);
>  void intel_dsc_disable(const struct intel_crtc_state *crtc_state);
> -int intel_dsc_compute_params(struct intel_crtc_state *pipe_config);
> +int intel_dsc_compute_params(struct intel_crtc_state *pipe_config,
> +			     struct intel_encoder *encoder);
>  void intel_dsc_get_config(struct intel_crtc_state *crtc_state);
>  enum intel_display_power_domain
>  intel_dsc_power_domain(struct intel_crtc *crtc, enum transcoder cpu_transcoder);

-- 
Jani Nikula, Intel