I tried booting 4.18.0-16-generic (which i believe is the hwe kernel) with kernel option drm.debug=0xff. When the system came up of course it had no video but I could ssh in and grab the dmesg output, which is attached to this message. dmesg had many drm-related debugging messages and i915-related messages, but none of it was particularly helpful to me yet.
I tried booting 4.18.0-16-generic (which i believe is the hwe kernel) with kernel option drm.debug=0xff. When the system came up of course it had no video but I could ssh in and grab the dmesg output, which is attached to this message. dmesg had many drm-related debugging messages and i915-related messages, but none of it was particularly helpful to me yet.