drm/edid: Don't send non-zero YQ in AVI infoframe for HDMI 1.x sinks

Apparently some sinks look at the YQ bits even when receiving RGB,
and they get somehow confused when they see a non-zero YQ value.
So we can't just blindly follow CEA-861-F and set YQ to match the
RGB range.

Unfortunately there is no good way to tell whether the sink
designer claims to have read CEA-861-F. The CEA extension block
revision number has generally been stuck at 3 since forever,
and even a very recently manufactured sink might be based on
an old design so the manufacturing date doesn't seem like
something we can use. In lieu of better information let's
follow CEA-861-F only for HDMI 2.0 sinks, since HDMI 2.0 is
based on CEA-861-F. For HDMI 1.x sinks we'll always set YQ=0.

The alternative would of course be to always set YQ=0. And if
we ever encounter a HDMI 2.0+ sink with this bug that's what
we'll probably have to do.

Cc: stable@vger.kernel.org
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Neil Kownacki <njkkow@gmail.com>
Reported-by: Neil Kownacki <njkkow@gmail.com>
Tested-by: Neil Kownacki <njkkow@gmail.com>
Fixes: fcc8a22cc905 ("drm/edid: Set YQ bits in the AVI infoframe according to CEA-861-F")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101639
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171108152504.12596-1-ville.syrjala@linux.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 6bb6337be920c6b440ef33f579832368feed86e5..fc7946eb6665c4f07e796ea9c348ffa4c1cc81c8 100644 (file)
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -4809,7 +4809,8 @@ 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)
+                                  bool rgb_quant_range_selectable,
+                                  bool is_hdmi2_sink)
 {
        /*
         * CEA-861:
@@ -4833,8 +4834,15 @@ drm_hdmi_avi_infoframe_quant_range(struct hdmi_avi_infoframe *frame,
         *  YQ-field to match the RGB Quantization Range being transmitted
         *  (e.g., when Limited Range RGB, set YQ=0 or when Full Range RGB,
         *  set YQ=1) and the Sink shall ignore the YQ-field."
+        *
+        * Unfortunate certain sinks (eg. VIZ Model 67/E261VA) get confused
+        * by non-zero YQ when receiving RGB. There doesn't seem to be any
+        * good way to tell which version of CEA-861 the sink supports, so
+        * we limit non-zero YQ to HDMI 2.0 sinks only as HDMI 2.0 is based
+        * on on CEA-861-F.
         */
-       if (rgb_quant_range == HDMI_QUANTIZATION_RANGE_LIMITED)
+       if (!is_hdmi2_sink ||
+           rgb_quant_range == HDMI_QUANTIZATION_RANGE_LIMITED)
                frame->ycc_quantization_range =
                        HDMI_YCC_QUANTIZATION_RANGE_LIMITED;
        else

diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index e8abea7594ec4a5e333162cd1457a0b5f7cf6124..3fed1d3ecdedfdd5b51d13d42924a21d2299fde3 100644 (file)
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -481,7 +481,8 @@ static void intel_hdmi_set_avi_infoframe(struct drm_encoder *encoder,
                                           crtc_state->limited_color_range ?
                                           HDMI_QUANTIZATION_RANGE_LIMITED :
                                           HDMI_QUANTIZATION_RANGE_FULL,
-                                          intel_hdmi->rgb_quant_range_selectable);
+                                          intel_hdmi->rgb_quant_range_selectable,
+                                          is_hdmi2_sink);
 
        /* TODO: handle pixel repetition for YCBCR420 outputs */
        intel_write_infoframe(encoder, crtc_state, &frame);

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 937da8dd65b8b02168aeee602225c8a3e3fa171e..8f71157a2b063b07a3d3c195ae5049a0ddcac03e 100644 (file)
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -433,7 +433,8 @@ static void vc4_hdmi_set_avi_infoframe(struct drm_encoder *encoder)
                                           vc4_encoder->limited_rgb_range ?
                                           HDMI_QUANTIZATION_RANGE_LIMITED :
                                           HDMI_QUANTIZATION_RANGE_FULL,
-                                          vc4_encoder->rgb_range_selectable);
+                                          vc4_encoder->rgb_range_selectable,
+                                          false);
 
        vc4_hdmi_write_infoframe(encoder, &frame);
 }

diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index 1e1908a6b1d66eddede740c60ccc5084e2f49deb..a992434ded999d1a6b77cf34dd26a2c0f5a8fbd9 100644 (file)
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -360,7 +360,8 @@ 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);
+                                  bool rgb_quant_range_selectable,
+                                  bool is_hdmi2_sink);
 
 /**
  * drm_eld_mnl - Get ELD monitor name length in bytes.