No HDR_OUTPUT_METADATA property on eDP port on Gen9 graphics (Coffeelake)
has_gamut_metadata_dip()
returns false if port == PORT_A
and DISPLAY_VER(i915)
< 11, however in [1] @vsyrjala says that it's not available on eDP for HSW/BDW (which are gen7.5/gen8).
My XPS 15 7590 has eDP HDR panel and HDR works in Windows.
I wonder if has_gamut_metadata_dip()
unreasonably disables HDR on eDP ports on Gen9-Gen10.
[1] https://patchwork.freedesktop.org/patch/479315/?series=101708&rev=1#comment_861240