wlr-gamma-control issues on Intel Xe
On Intel Xe, sequential updates of gamma LUTs lead to display corruption. Setting the same LUT multiple times in sequence has a tendency to clean things up (although not always), so maybe a race is involved.
We have made a minimal reproduction that simply toggles between two different "gamma" values over in wlsunset on a branch: https://git.sr.ht/~kennylevinsen/wlsunset/tree/raw-debug/item/main.c.
I assume that the trigger that causes this to affect Intel Xe is the introduction of massive user-space gamma LUT requirements - LUTs measured in megabytes - which stem from the driver implementing non-linear gamma LUTs by simply skipping most values.