Dell Latitude D630
[drm:drm_atomic_helper_wait_for_flip_done [drm_kms_helper]] *ERROR* [CRTC:41:pipe B] flip_done timed out [drm:drm_atomic_helper_wait_for_dependencies [drm_kms_helper]] *ERROR* [PLANE:35:plane B] flip_done timed out
There is also a significant delay when logging in or unlocking a locked session during which I get a black screen.. None of these issues were present in LMDE 2 but are present in 18.3 and all 3 variants of 19 (i've tried these from live USBs), so it could be a regression in the newer kernels. Once actually logged in everything functions fine.
The fix: vim /etc/default/grub
... GRUB_TIMEOUT=1 GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video=SVIDEO-1:d" ...