Xorg spikes 100 percent CPU, very slow in redraw after unlocking screensaver (light-locker/lightdm)

If I let my computer go idle, either by directly locking the screen with light-locker, or letting light-locker time out and lock the screen, when I unlock the system with the lightdm greeter, all I will see is my urxvt terminal window with no text, my xfce panel completely blank, and no other windows. The mouse cursor moves very jerky and slow. If I log into the system via SSH (changing to one of the other virtual terminals does not work), I see that Xorg has pegged one CPU at 100 percent.

If I let it sit and wait, it eventually comes back, and Xorg goes back to normal CPU usage. I don’t see anything in the Xorg.0.log which indicates a problem. The only reason I’m mentioning this on this forum is that changing to the nouveau driver doesn’t exhibit this exact problem. With nouveau I have issues with DPMS not working at all.

Here’s the output of nvidia-bug-report.sh: http://filebin.ca/2iiHvgMX1iH7/nvidia-bug-report.log.gz