Re: [PATCH 4/5] drm/edid: Set AVI infoframe Q even when QS=0

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

On Wed, 11 Jan 2017, ville.syrjala@linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> HDMI 2.0 recommends that we set the Q bits in the AVI infoframe
> even when the sink does not support quantization range selection (QS=0).
> According to CEA-861 we can do that as long as the Q we send matches
> the default quantization range for the mode.
>
> Previosuly I think I had misread the spec as saying that you can't
  ^^^^^^^^^^

> send a non-zero Q at all when QS=0. But that's not what the spec
> actually says.

Agreed.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/drm_edid.c        | 8 +++++++-
>  drivers/gpu/drm/i915/intel_hdmi.c | 6 ++++--
>  drivers/gpu/drm/vc4/vc4_hdmi.c    | 2 +-
>  include/drm/drm_edid.h            | 1 +
>  4 files changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 548c20250b95..caa2435bac31 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -4295,11 +4295,13 @@ EXPORT_SYMBOL(drm_hdmi_avi_infoframe_from_display_mode);
>   * drm_hdmi_avi_infoframe_quant_range() - fill the HDMI AVI infoframe
>   *                                        quantization range information
>   * @frame: HDMI AVI infoframe
> + * @mode: DRM display mode
>   * @rgb_quant_range: RGB quantization range (Q)
>   * @rgb_quant_range_selectable: Sink support selectable RGB quantization range (QS)
>   */
>  void
>  drm_hdmi_avi_infoframe_quant_range(struct hdmi_avi_infoframe *frame,
> +				   const struct drm_display_mode *mode,
>  				   enum hdmi_quantization_range rgb_quant_range,
>  				   bool rgb_quant_range_selectable)
>  {
> @@ -4309,8 +4311,12 @@ drm_hdmi_avi_infoframe_quant_range(struct hdmi_avi_infoframe *frame,
>  	 *  to the default RGB Quantization Range for the transmitted Picture
>  	 *  unless the Sink indicates support for the Q bit in a Video
>  	 *  Capabilities Data Block."
> +	 *
> +	 * HDMI 2.0 recommends sending non-zero Q when it does match the
> +	 * default RGB quantization range for the mode, even when QS=0.
>  	 */
> -	if (rgb_quant_range_selectable)
> +	if (rgb_quant_range_selectable ||
> +	    rgb_quant_range == drm_default_rgb_quant_range(mode))
>  		frame->quantization_range = rgb_quant_range;
>  	else
>  		frame->quantization_range = HDMI_QUANTIZATION_RANGE_DEFAULT;
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index 351f837b09a0..af16b0fa6b69 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -455,17 +455,19 @@ static void intel_hdmi_set_avi_infoframe(struct drm_encoder *encoder,
>  					 const struct intel_crtc_state *crtc_state)
>  {
>  	struct intel_hdmi *intel_hdmi = enc_to_intel_hdmi(encoder);
> +	const struct drm_display_mode *adjusted_mode =
> +		&crtc_state->base.adjusted_mode;
>  	union hdmi_infoframe frame;
>  	int ret;
>  
>  	ret = drm_hdmi_avi_infoframe_from_display_mode(&frame.avi,
> -						       &crtc_state->base.adjusted_mode);
> +						       adjusted_mode);
>  	if (ret < 0) {
>  		DRM_ERROR("couldn't fill AVI infoframe\n");
>  		return;
>  	}
>  
> -	drm_hdmi_avi_infoframe_quant_range(&frame.avi,
> +	drm_hdmi_avi_infoframe_quant_range(&frame.avi, adjusted_mode,
>  					   crtc_state->limited_color_range ?
>  					   HDMI_QUANTIZATION_RANGE_LIMITED :
>  					   HDMI_QUANTIZATION_RANGE_FULL,
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> index a588156b5410..f38fdbac2878 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> @@ -356,7 +356,7 @@ static void vc4_hdmi_set_avi_infoframe(struct drm_encoder *encoder)
>  		return;
>  	}
>  
> -	drm_hdmi_avi_infoframe_quant_range(&frame.avi,
> +	drm_hdmi_avi_infoframe_quant_range(&frame.avi, mode,
>  					   vc4_encoder->limited_rgb_range ?
>  					   HDMI_QUANTIZATION_RANGE_LIMITED :
>  					   HDMI_QUANTIZATION_RANGE_FULL,
> diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
> index cfad4d89589f..43fb0ac5eb9c 100644
> --- a/include/drm/drm_edid.h
> +++ b/include/drm/drm_edid.h
> @@ -347,6 +347,7 @@ drm_hdmi_vendor_infoframe_from_display_mode(struct hdmi_vendor_infoframe *frame,
>  					    const struct drm_display_mode *mode);
>  void
>  drm_hdmi_avi_infoframe_quant_range(struct hdmi_avi_infoframe *frame,
> +				   const struct drm_display_mode *mode,
>  				   enum hdmi_quantization_range rgb_quant_range,
>  				   bool rgb_quant_range_selectable);

-- 
Jani Nikula, Intel Open Source Technology Center
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