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. Fixes: 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@xxxxxxx> Cc: Pekka Paalanen <ppaalanen@xxxxxxxxx> Cc: Sebastian Wick <sebastian.wick@xxxxxxxxxx> Cc: Vitaly.Prosyak@xxxxxxx Cc: Uma Shankar <uma.shankar@xxxxxxxxx> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Cc: Joshua Ashton <joshua@xxxxxxxxx> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx Acked-by: Pekka Paalanen <pekka.paalanen@xxxxxxxxxxxxx> --- drivers/gpu/drm/display/drm_hdmi_helper.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/display/drm_hdmi_helper.c b/drivers/gpu/drm/display/drm_hdmi_helper.c index 0264abe55278..faf5e9efa7d3 100644 --- a/drivers/gpu/drm/display/drm_hdmi_helper.c +++ b/drivers/gpu/drm/display/drm_hdmi_helper.c @@ -44,10 +44,8 @@ int drm_hdmi_infoframe_set_hdr_metadata(struct hdmi_drm_infoframe *frame, /* Sink EOTF is Bit map while infoframe is absolute values */ if (!is_eotf_supported(hdr_metadata->hdmi_metadata_type1.eotf, - connector->hdr_sink_metadata.hdmi_type1.eotf)) { - DRM_DEBUG_KMS("EOTF Not Supported\n"); - return -EINVAL; - } + connector->hdr_sink_metadata.hdmi_type1.eotf)) + DRM_DEBUG_KMS("Unknown EOTF %d\n", hdr_metadata->hdmi_metadata_type1.eotf); err = hdmi_drm_infoframe_init(frame); if (err < 0) -- 2.38.1
