Created attachment 83002 [details]
Xorg.0.log with modeset enabled and output of dmesg while problem is active

When using nouveau with modeset, the system starts up fine but eventually
(possibly when the screen saver kicks in), X consumes all CPU resources on one
core rendering the machine useless except via ssh sessions. If I disable
modeset at boot time (nouveau.modeset=0), then the system is stable but the
drive does not accept the EDID from the monitor and I'm stuck with a 1024x768
display instead of the 1600x900 it has with modeset enabled.

I'm attaching the Xorg.0.log file along with an excerpt from the output of
dmesg when this behavior is occurring.