drm/amd/display: DGAM enabled for HDR

[Why]
On HW that doesn't have input LUT, we may combine degamma with OS ramp
Problem here is that it assumes DGAM is inverse of PQ or SRGB. It doesn't
handle linear case, it would default to sRGB and always enable DGAM..

[How] Add handling for linear case. Also check for null ramp and instead of
blowing up, assume it's identity.

Signed-off-by: Krunoslav Kovac <[email protected]>
Reviewed-by: Anthony Koo <[email protected]>
Acked-by: Bhawanpreet Lakha <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

0 files changed, 0 insertions, 0 deletions