Re: [PATCH 2/7] drm/i915/display: Prepare for dsc 3 stream splitter

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 10/27/2024 7:15 PM, Ankit Nautiyal wrote:
> At the moment dsc_split represents whether the dsc splitter is used
> or not. With 3 DSC engines, the splitter can split into two streams
> or three streams.
>
> Instead of representing the splitter's state, it is more effective to
> represent the number of DSC streams per pipe.
>
> Replace the `dsc.dsc_split` member with `dsc.num_streams` to indicate the
> number of DSC streams used per pipe. This change will implicitly
> convey the splitter's operation mode.
>
> v2: Avoid new enum for dsc split. (Suraj)
> v3:
> -Replace dsc_split with num_stream. (Suraj)
> -Avoid extra parentheses. (Jani)
>
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
> ---
>   drivers/gpu/drm/i915/display/icl_dsi.c           |  4 +++-
>   drivers/gpu/drm/i915/display/intel_display.c     |  2 +-
>   .../gpu/drm/i915/display/intel_display_types.h   |  2 +-
>   drivers/gpu/drm/i915/display/intel_dp.c          |  4 +++-
>   drivers/gpu/drm/i915/display/intel_vdsc.c        | 16 +++++++++++-----
>   5 files changed, 19 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c b/drivers/gpu/drm/i915/display/icl_dsi.c
> index 115d79c80b9a..b01dfbeb314b 100644
> --- a/drivers/gpu/drm/i915/display/icl_dsi.c
> +++ b/drivers/gpu/drm/i915/display/icl_dsi.c
> @@ -1596,7 +1596,9 @@ static int gen11_dsi_dsc_compute_config(struct intel_encoder *encoder,
>   
>   	/* FIXME: split only when necessary */
>   	if (crtc_state->dsc.slice_count > 1)
> -		crtc_state->dsc.dsc_split = true;
> +		crtc_state->dsc.num_streams = 2;
> +	else
> +		crtc_state->dsc.num_streams = 1;
>   
>   	/* FIXME: initialize from VBT */
>   	vdsc_cfg->rc_model_size = DSC_RC_MODEL_SIZE_CONST;
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index ef1436146325..3dfff0a8c386 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -5741,7 +5741,7 @@ intel_pipe_config_compare(const struct intel_crtc_state *current_config,
>   	PIPE_CONF_CHECK_I(dsc.config.nsl_bpg_offset);
>   
>   	PIPE_CONF_CHECK_BOOL(dsc.compression_enable);
> -	PIPE_CONF_CHECK_BOOL(dsc.dsc_split);
> +	PIPE_CONF_CHECK_I(dsc.num_streams);
>   	PIPE_CONF_CHECK_I(dsc.compressed_bpp_x16);
>   
>   	PIPE_CONF_CHECK_BOOL(splitter.enable);
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 2bb1fa64da2f..5611a4dd6a6f 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1235,7 +1235,7 @@ struct intel_crtc_state {
>   	/* Display Stream compression state */
>   	struct {
>   		bool compression_enable;
> -		bool dsc_split;
> +		int num_streams;
>   		/* Compressed Bpp in U6.4 format (first 4 bits for fractional part) */
>   		u16 compressed_bpp_x16;
>   		u8 slice_count;
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index bd9f37e1a13f..dbb1d75c0576 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -2410,7 +2410,9 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
>   	 * then we need to use 2 VDSC instances.
>   	 */
>   	if (pipe_config->joiner_pipes || pipe_config->dsc.slice_count > 1)
> -		pipe_config->dsc.dsc_split = true;
> +		pipe_config->dsc.num_streams = 2;
> +	else
> +		pipe_config->dsc.num_streams = 1;
>   
>   	ret = intel_dp_dsc_compute_params(connector, pipe_config);
>   	if (ret < 0) {
> diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.c b/drivers/gpu/drm/i915/display/intel_vdsc.c
> index 40525f5c4c42..afc40d180dec 100644
> --- a/drivers/gpu/drm/i915/display/intel_vdsc.c
> +++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
> @@ -379,7 +379,7 @@ intel_dsc_power_domain(struct intel_crtc *crtc, enum transcoder cpu_transcoder)
>   
>   static int intel_dsc_get_vdsc_per_pipe(const struct intel_crtc_state *crtc_state)
>   {
> -	return crtc_state->dsc.dsc_split ? 2 : 1;
> +	return crtc_state->dsc.num_streams;
>   }
>   
>   int intel_dsc_get_num_vdsc_instances(const struct intel_crtc_state *crtc_state)
> @@ -976,8 +976,14 @@ void intel_dsc_get_config(struct intel_crtc_state *crtc_state)
>   	if (!crtc_state->dsc.compression_enable)
>   		goto out;
>   
> -	crtc_state->dsc.dsc_split = (dss_ctl2 & RIGHT_BRANCH_VDSC_ENABLE) &&
> -		(dss_ctl1 & JOINER_ENABLE);
> +	if (dss_ctl1 & JOINER_ENABLE) {
> +		if (dss_ctl2 & RIGHT_BRANCH_VDSC_ENABLE)
> +			crtc_state->dsc.num_streams = 2;
> +		else
> +			crtc_state->dsc.num_streams = 1;
> +	} else {
> +		crtc_state->dsc.num_streams = 0;

I realized that this is a mistake, num_streams cannot be 0 when 
dsc.compression_enable is set.

Will correct this to num_streams = 1, and simplify the if-else block.

Regards,

Ankit


> +	}
>   
>   	intel_dsc_get_pps_config(crtc_state);
>   out:
> @@ -988,10 +994,10 @@ static void intel_vdsc_dump_state(struct drm_printer *p, int indent,
>   				  const struct intel_crtc_state *crtc_state)
>   {
>   	drm_printf_indent(p, indent,
> -			  "dsc-dss: compressed-bpp:" FXP_Q4_FMT ", slice-count: %d, split: %s\n",
> +			  "dsc-dss: compressed-bpp:" FXP_Q4_FMT ", slice-count: %d, num_streams: %d\n",
>   			  FXP_Q4_ARGS(crtc_state->dsc.compressed_bpp_x16),
>   			  crtc_state->dsc.slice_count,
> -			  str_yes_no(crtc_state->dsc.dsc_split));
> +			  crtc_state->dsc.num_streams);
>   }
>   
>   void intel_vdsc_state_dump(struct drm_printer *p, int indent,