acpivout leads to hangs with running x-windows

[bonds]

After a couple hours of running X, either FVWM or Xfce or Gnome, ends in Xorg freezing up. Top reveals that the Xorg process is in the 'acpilk' state. I can SSH into the box but I cannot switch between virtual consoles, the screen stays frozen. If I issue a reboot command, the screen stays frozen until just before reboot, then the last few lines of text before reboot are visible.

Workaround: disabling the acpivout device eliminates this hang. To do so, you should configure a new copy of the kernel and set it to be your default:

$ config -o /bsd -e /bsd.fixed
> disable acpivout
> quit
$ echo "bsd.fixed" > /etc/boot.conf

One side effect I've encountered is GDM sometimes exhibiting a strange behavior that prevented me from unlocking the screen after the screensaver had kicked in. I do not seem to encounter this when acpivout is enabled.

TODO: attach a video of the side effect.