From: Ville Syrjälä ville.syrjala@linux.intel.com

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 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 --- drivers/gpu/drm/drm_edid.c | 12 ++++++++++-- drivers/gpu/drm/i915/intel_hdmi.c | 3 ++- drivers/gpu/drm/vc4/vc4_hdmi.c | 3 ++- include/drm/drm_edid.h | 3 ++- 4 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 749d07a01772..8567890f47a7 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -4838,7 +4838,8 @@ 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: @@ -4862,8 +4863,15 @@ 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 fa1c793a21ef..2b23d3662eec 100644 --- a/drivers/gpu/drm/i915/intel_hdmi.c +++ b/drivers/gpu/drm/i915/intel_hdmi.c @@ -487,7 +487,8 @@ 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 9a9a6b4acccf..d645df0c6d15 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -423,7 +423,8 @@ 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 9e4e23524840..58ffb68efdc5 100644 --- a/include/drm/drm_edid.h +++ b/include/drm/drm_edid.h @@ -361,7 +361,8 @@ 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.