From: Harry Wentland harry.wentland@amd.com
commit e5eef23e267c72521d81f23f7f82d1f523d4a253 upstream.
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.w... Signed-off-by: Alex Deucher alexander.deucher@amd.com Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/display/drm_hdmi_helper.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
--- 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(
/* 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)