https://bugs.freedesktop.org/show_bug.cgi?id=107518
--- Comment #3 from Alex Deucher alexdeucher@gmail.com --- (In reply to Shawn Anastasio from comment #2)
Upon further testing, the issue seems to go away when the firmware is removed from petitboot, preventing it from initializing the card before the host OS. This indicates that it may have something to do with the GPU being initialized twice.
The hw requires a special reset before it can be initialized again. This is handled in driver for things like hibernate (S4) support.