This is a weird one. I was playing the Talos Principle while hacking xboxdrv to support the Steam Controller. While switching windows, it got into an odd state and the whole display froze. I was able to ssh in from another machine and issue a reboot but after losing contact, it didn't actually reboot. I hit the power button.
When X came back up, it had weird red artifacts all over the place. It's hard to describe so here's a screenshot.
I tried rebooting again. Same thing. I'm on Gentoo so I tried upgrading/downgrading various things but nothing has made any difference. I was then notified of a Gentoo forum thread where another user had encountered the same thing following some kind of crash or freeze in QuDos (Quake 2). This is his screenshot.
The only thing I upgraded since the previous reboot that could possibly be related was LLVM from 3.9.0 to 3.9.1. I haven't downgraded that because it takes ages to build and I doubt that is the cause.
I have fired up the Talos Principle again in the hope that it would knock things back into the shape. The game looks fine but the desktop remains unchanged.
I tried firing up Weston (which I don't normally use) and it didn't show the same corruption when I launched Thunar. That may be a red herring. Excuse the pun. :)
linux: 4.9 (and 4.8.14)
xf86-video-amdgpu: b5c189473d (and 1.2.0)
libdrm: eebefaf72c (and 2.4.74)
Sorry, forgot the most important bit, it's an RX 480.
*** This bug has been marked as a duplicate of bug 99078 ***
This involves llvm change anyway, but more generally, rebooting or (soft) power off really doesn't totally reset GPUs.
You need to shutdown/soft power off the best you can and then totally cut power by turning off PSU switch or unplugging. You should then wait a couple of minutes to be sure everything has "drained" before powering up again.
(In reply to Andy Furniss from comment #3)
> This involves llvm change anyway, but more generally, rebooting or (soft)
> power off really doesn't totally reset GPUs.
> You need to shutdown/soft power off the best you can and then totally cut
> power by turning off PSU switch or unplugging. You should then wait a couple
> of minutes to be sure everything has "drained" before powering up again.
Yeah, I actually meant shutdown so power was off but I didn't wait long. Good to know this can still be a factor, thanks.
Sorry for the duplicate, I honestly didn't think LLVM is involved in rendering desktop icons. I've rebuilt without that commit and all is good now.