I noticed the past few weeks that Linux (both Ubuntu and Linux Mint) has been misbehaving when I switch between computers using my 2 port iogear KVM switch. When switching back to Linux the desktop display mode gets switched to 640×480, which looks terrible on the screen. I found an easy workaround: hit the “windows” key to activate the Cinnamon menu, type in Display to bring up the Display dialog box. When the Display dialog box loads it automatically switches back to 1920×1080.
Not sure if the problem is that the digital signal can’t get through the KVM to the computer correctly, but this seems to be a recent happening. I’m not sure this happened before. Considering I’m still using DSUB/VGA I’d think this shouldn’t really be an issue. There are a bunch of new elements I’ve introduced that make diagnosis a bit more difficult: new flavour of Linux (though it happened on Ubuntu 12.10 too), different monitor and the mouse connected to the keyboard (USB hub) instead of the switch.
The work-around isn’t a bad solution and the problem doesn’t always happen, so it could be a sleep/hibernation-related issue.