[AMD Official Use Only - General]
I found out that elsewhere in the drm code (e.g. in drm_atomic_helper.c)
expects drm_vblank_get() to fail as part of normal operation. So this patch
doesn't seem appropriate anymore and it seems more appropriate to hunt down all
the unchecked calls for
drm_crtc_vblank_off increments the refcount to prevent vblank from
getting enabled during modeset, but this causes the refcount elsewhere
to be off if they call drm_vblank_get without checking the return and
do a drm_vblank_put later. This can be reproduced by toggling vrr mode
on amdgpu.
Since
