Re: [PATCH 10/20] drm/i915: add config function for YCBCR420 outputs

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

On Mon, Jul 10, 2017 at 04:48:38PM +0530, Shashank Sharma wrote:
> This patch checks encoder level support for YCBCR420 outputs.
> The logic goes as simple as this:
> If the input mode is YCBCR420-only mode: prepare HDMI for
> YCBCR420 output, else continue with RGB output mode.
> 
> It checks if the mode is YCBCR420 and source can support this
> output then it marks the ycbcr_420 output indicator into crtc
> state, for further staging in driver.
> 
> V2: Split the patch into two, kept helper functions in DRM layer.
> V3: Changed the compute_config function based on new DRM API.
> V4: Rebase
> V5: Rebase
> V6: Check and handle YCBCR420-only modes, discard the property
>     based approach (Ville)
> 
> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c |  1 +
>  drivers/gpu/drm/i915/intel_drv.h     |  3 +++
>  drivers/gpu/drm/i915/intel_hdmi.c    | 42 +++++++++++++++++++++++++++++++++---
>  3 files changed, 43 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 4e03ca6..01900e1 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -11930,6 +11930,7 @@ intel_pipe_config_compare(struct drm_i915_private *dev_priv,
>  	PIPE_CONF_CHECK_I(hdmi_scrambling);
>  	PIPE_CONF_CHECK_I(hdmi_high_tmds_clock_ratio);
>  	PIPE_CONF_CHECK_I(has_infoframe);
> +	PIPE_CONF_CHECK_I(ycbcr420);
>  
>  	PIPE_CONF_CHECK_I(has_audio);
>  
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index d17a324..592243b 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -780,6 +780,9 @@ struct intel_crtc_state {
>  
>  	/* HDMI High TMDS char rate ratio */
>  	bool hdmi_high_tmds_clock_ratio;
> +
> +	/* HDMI output type */
> +	bool ycbcr420;
>  };
>  
>  struct intel_crtc {
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index cc0d100..276d916 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -1305,7 +1305,8 @@ intel_hdmi_mode_valid(struct drm_connector *connector,
>  	return status;
>  }
>  
> -static bool hdmi_12bpc_possible(struct intel_crtc_state *crtc_state)
> +static bool hdmi_12bpc_possible(struct intel_crtc_state *crtc_state,
> +				bool output_ycbcr420)

You alreayd have the crtc state, so no need to pass that stuff
separately.

>  {
>  	struct drm_i915_private *dev_priv =
>  		to_i915(crtc_state->base.crtc->dev);
> @@ -1330,6 +1331,13 @@ static bool hdmi_12bpc_possible(struct intel_crtc_state *crtc_state)
>  		if (connector_state->crtc != crtc_state->base.crtc)
>  			continue;
>  
> +		if (output_ycbcr420) {
> +			const struct drm_hdmi_info *hdmi = &info->hdmi;
> +
> +			if (!(hdmi->y420_dc_modes & DRM_EDID_YCBCR420_DC_36))
> +				return false;
> +		}
> +

else?

>  		if ((info->edid_hdmi_dc_modes & DRM_EDID_HDMI_DC_36) == 0)
>  			return false;
>  	}
> @@ -1342,6 +1350,25 @@ static bool hdmi_12bpc_possible(struct intel_crtc_state *crtc_state)
>  	return true;
>  }
>  
> +static bool
> +intel_hdmi_ycbcr420_config(struct drm_connector *connector,
> +			       struct intel_crtc_state *config,
> +			       int *clock_12bpc, int *clock_8bpc)
> +{
> +
> +	if (!connector->ycbcr_420_allowed) {
> +		DRM_ERROR("Platform doesn't support YCBCR420 output\n");
> +		return false;
> +	}
> +
> +	/* YCBCR420 TMDS rate requirement is half the pixel clock */
> +	config->port_clock /= 2;
> +	*clock_12bpc /= 2;
> +	*clock_8bpc /= 2;
> +	config->ycbcr420 = true;
> +	return true;
> +}
> +
>  bool intel_hdmi_compute_config(struct intel_encoder *encoder,
>  			       struct intel_crtc_state *pipe_config,
>  			       struct drm_connector_state *conn_state)
> @@ -1349,7 +1376,8 @@ bool intel_hdmi_compute_config(struct intel_encoder *encoder,
>  	struct intel_hdmi *intel_hdmi = enc_to_intel_hdmi(&encoder->base);
>  	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
>  	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
> -	struct drm_scdc *scdc = &conn_state->connector->display_info.hdmi.scdc;
> +	struct drm_connector *connector = conn_state->connector;
> +	struct drm_scdc *scdc = &connector->display_info.hdmi.scdc;
>  	struct intel_digital_connector_state *intel_conn_state =
>  		to_intel_digital_connector_state(conn_state);
>  	int clock_8bpc = pipe_config->base.adjusted_mode.crtc_clock;
> @@ -1379,6 +1407,14 @@ bool intel_hdmi_compute_config(struct intel_encoder *encoder,
>  		clock_12bpc *= 2;
>  	}
>  
> +	if (drm_mode_is_420_only(&connector->display_info, adjusted_mode)) {
> +		if (!intel_hdmi_ycbcr420_config(connector, pipe_config,
> +						&clock_12bpc, &clock_8bpc)) {
> +			DRM_ERROR("Can't support YCBCR420 output\n");
> +			return false;
> +		}
> +	}
> +
>  	if (HAS_PCH_SPLIT(dev_priv) && !HAS_DDI(dev_priv))
>  		pipe_config->has_pch_encoder = true;
>  
> @@ -1398,7 +1434,7 @@ bool intel_hdmi_compute_config(struct intel_encoder *encoder,
>  	 */
>  	if (pipe_config->pipe_bpp > 8*3 && pipe_config->has_hdmi_sink && !force_dvi &&
>  	    hdmi_port_clock_valid(intel_hdmi, clock_12bpc, true, force_dvi) == MODE_OK &&
> -	    hdmi_12bpc_possible(pipe_config)) {
> +	    hdmi_12bpc_possible(pipe_config, pipe_config->ycbcr420)) {
>  		DRM_DEBUG_KMS("picking bpc to 12 for HDMI output\n");
>  		desired_bpp = 12*3;
>  
> -- 
> 2.7.4
> 
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-- 
Ville Syrjälä
Intel OTC
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