I've experienced an issue where hardware acceleration of my Intel i945 mobile display chip set has been disabled during an in-place upgrade from 17.10 to 18.04.
Unfortunately none of the existing filed bugs I've found seem related to my problem, or at least the fixes don't work for me.
Any ideas of where I could start looking for error messages related to this? (eg X.org logs etc etc) or remedies I could try?
FWIW, hardware acceleration under a live-cd boot of 18.04 seems to work fine and all resolutions are available and it was also working perfectly under 17.10.
I also had to add "nomodeset" to grub boot commands, otherwise machine would hang during boot process
Barring any options, the simplest fix may be a re-install but that seems drastic for something like this.