Overall looks good, but it is a bit repetitive to copy & paste this in all
drivers. It'd be nice to provide a core helper to do this, and then drivers
can just set format_mod_supported to the helper if they don't have more
involved logic. Thoughts?
See drm_plane_check_pixel_format, where the
Where no modifiers are exposed, usually linear modifier is assumed.
However, userspace code is starting to expect IN_FORMATS even when the
only supported modifiers are linear [1].
To avoid possible issues, explicitly set the DRM_FORMAT_MOD_LINEAR
modifier.
[1]
