System font alternates

Question

I've got a very curious problem, in which on my laptop (initially installed with Ubuntu 14.04, then upgraded on 16.04), the system font alternates with each reboot (well, sometimes it's bad 3 reboots in a row)... Sometimes I get the "normal" standard Ubuntu font that everybody knows and loves, and sometimes I get this abomination:

This happens system-wide (so before I log in into my account), not only for my user.

I tried running gnome-tweak-tool, changing the settings for the Fonts (including the Antialiasing), but nothing helped. Atm it looks like this:

This problem definitely came with an update, but I don't remember which one. Any ideas on how to fix it?

Answer 1

I don't think you're seeing different fonts but actually just different rendering methods of the same font. That font looks very thin and skinny because it has no "hinting" on it and it looks like when this happens you also don't get sub-pixel precision for you fonts either.

I think this happens because sometimes when your system boots it doesn't see the display as a laptop, or possibly it sees another output device and disables sub-pixel rendering.

My advice is next time this happens try going to the Display manager and changing your resolution in an attempt to tell Ubuntu to find your displays again. It's possible this won't help because the driver stack is already loaded and committed to not doing sub-pixel rendering, but I'm not positive.