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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>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.