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

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>

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index bca73a8..292cb50 100644 (file)
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -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;

diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index 351f837..af16b0f 100644 (file)
--- 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 87b5946..93d5994 100644 (file)
--- 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 cfad4d8..43fb0ac 100644 (file)
--- 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);