From 9271c0ca573e02a360b636ecd8cb408852f4e9f6 Mon Sep 17 00:00:00 2001 From: Ville Syrjälä Date: Wed, 8 Nov 2017 17:25:04 +0200 Subject: drm/edid: Don't send non-zero YQ in AVI infoframe for HDMI 1.x sinks MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Cc: Eric Anholt Cc: Neil Kownacki Reported-by: Neil Kownacki Tested-by: Neil Kownacki 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 Link: https://patchwork.freedesktop.org/patch/msgid/20171108152504.12596-1-ville.syrjala@linux.intel.com Acked-by: Eric Anholt --- drivers/gpu/drm/vc4/vc4_hdmi.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/gpu/drm/vc4') diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c index 937da8dd65b8..8f71157a2b06 100644 --- 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); } -- cgit