From your logs it looks like the problem is that something is probing the VGA output repeatedly, and you're the lucky owner of some hardware that flickers when probed (it's not uncommon).
You could check this by adding “drm_kms_helper.poll=0” on the kernel command line; that should disable polling on the VGA (and, indeed, all other) output.
From your logs it looks like the problem is that something is probing the VGA output repeatedly, and you're the lucky owner of some hardware that flickers when probed (it's not uncommon).
You could check this by adding “drm_kms_ helper. poll=0” on the kernel command line; that should disable polling on the VGA (and, indeed, all other) output.