[SOLVED] "GPU hung" error after system update, X unusable

[MF_Luder]

Yesterday I ran "emerge -avuDN world" for the first time in a few months, which is longer than I normally go without doing that. Since then, I have been having horrible video problems. X will not run if I have an ~/.xinitrc script. It will exit immediately as if it has finished running the script, no matter what is in the script. Without an ~/.xinitrc script, it will start, but wherever the screen changes, whether it's because a window is moving or resizing or because the contents of a window are changing, the change lags noticeably behind the input that causes it, and happens very slowly, a few pixels at a time. The effect is more dramatic in some instances than in others, but the only thing that seems to be completely unaffected is the cursor.

There doesn't seem to be anything unusual in /var/log/Xorg.0.log, but the bottom of dmesg looks like this:

[MF_Luder]

The solution to this problem was to downgrade x11-drivers/xf86-video-intel. I added ">=x11-drivers/xf-video-intel-2.99.912" to /etc/portage/package.mask and emerged version 2.99.911-r1, and problem solved. I had tried to do this yesterday and masking that package seemed to have no effect on the version that was emerged. Maybe that was the result of a typo or something like that, or maybe there had been something overriding package.mask. I've changed a lot of things in the past 48 hours, so I don't know what the deal with that was.

Apparently one difference between VIDEO_CARDS="intel" and VIDEO_CARDS="i965" is that VIDEO_CARDS="intel" causes things to depend on x11-drivers/xf86-video-intel and VIDEO_CARDS="i965" does not. Normally replacing "intel" with "i965" and running "emerge -uDN world" and "emerge --depclean" would have removed xf86-video-intel, but in my case I have installed it explicitly at some point, and so --depclean didn't remove it. Once it was removed, the video problem was gone, but xrandr wasn't working. With an older version of it installed, everything works. Currently I have VIDEO_CARDS set to "intel i965".

I was still having some trouble with my .xinitrc script, but I eventually sorted that out via trial and error. It seems to me like there is something different about the way that this script it run now, but unfortunately I've changed it so much in my attempts to get it to work that I don't remember exactly what it originally looked like, or how my current one is different from my old one.