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drm/edid: Set AVI infoframe Q even when QS=0

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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.

Previously 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.

v2: Fix typo in commit message (Jani)

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170111125725.8086-5-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Eric Anholt <eric@anholt.net>
This commit is contained in:
Ville Syrjälä
2017-01-11 14:57:24 +02:00
parent a2ce26f815
commit 779c4c2866
4 changed files with 13 additions and 4 deletions
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8
drivers/gpu/drm/drm_edid.c
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@@ -4296,11 +4296,13 @@ 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)
{
@@ -4310,8 +4312,12 @@ 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;