CTA-861-G section 6.9.1 Static Metadata Type 1 declares that zero values
for different groups of HDR Metadata properties are allowed, including
zero nits values for max display mastering luminance, max content light
level, max frame-average light level and min display mastering luminance.
A zero value is meant to be treated by the video sink as "undefined" /
"unknown", and handled accordingly. This is common for dynamically
generated visual content.
The is_hdr_metadata_legal() function in the Vulkan/WSI/Wayland HDR backend
currently declares HDR light level metadata as invalid if the mastering
display min_luminance and max_luminance light levels are set to the legal
level of zero nits. This causes valid HDR metadata as set by the client
via vkSetHdrMetadata() to be not sent to the compositor.
Fix this by skipping checks that don't apply if min_luminance or
max_luminance are zero. If max_luminance is zero then we skip sending
of mastering display min/max luminance to Wayland, as sending a a
max_luminance <= min_luminance would trigger a protocol error. All
other valid data is still send, ie. color primaries, white-point,
content light levels.
Fixes: cb7726bb2c ("vulkan/wsi: validate HDR metadata to not cause protocol errors")
Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Co-authored-by: Michel Dänzer <michel@daenzer.net>
Reviewed-by: Xaver Hugl <xaver.hugl@kde.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38326>
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