2f60eded72
The EDID of an HDR display defines EOTFs that are supported by the display and can be set in the HDR metadata infoframe. Userspace is expected to read the EDID and set an appropriate HDR_OUTPUT_METADATA. In drm_parse_hdr_metadata_block the kernel reads the supported EOTFs from the EDID and stores them in the drm_connector->hdr_sink_metadata. While doing so it also filters the EOTFs to the EOTFs the kernel knows about. When an HDR_OUTPUT_METADATA is set it then checks to make sure the EOTF is a supported EOTF. In cases where the kernel doesn't know about a new EOTF this check will fail, even if the EDID advertises support. Since it is expected that userspace reads the EDID to understand what the display supports it doesn't make sense for DRM to block an HDR_OUTPUT_METADATA if it contains an EOTF the kernel doesn't understand. This comes with the added benefit of future-proofing metadata support. If the spec defines a new EOTF there is no need to update DRM and an compositor can immediately make use of it. Bug: https://gitlab.freedesktop.org/wayland/weston/-/issues/609 v2: Distinguish EOTFs defind in kernel and ones defined in EDID in the commit description (Pekka) v3: Rebase; drm_hdmi_infoframe_set_hdr_metadata moved to drm_hdmi_helper.c Signed-off-by: Harry Wentland <harry.wentland@amd.com> Cc: Pekka Paalanen <ppaalanen@gmail.com> Cc: Sebastian Wick <sebastian.wick@redhat.com> Cc: Vitaly.Prosyak@amd.com Cc: Uma Shankar <uma.shankar@intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Joshua Ashton <joshua@froggi.es> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: dri-devel@lists.freedesktop.org Cc: amd-gfx@lists.freedesktop.org Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com> Reviewed-By: Joshua Ashton <joshua@froggi.es> Link: https://patchwork.freedesktop.org/patch/msgid/20230113162428.33874-2-harry.wentland@amd.com Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.