As a workaround, I've discovered that switching to EXA acceleration seems to work. To do that, open the file /etc/X11/xorg.conf and make sure you have a section that looks like:
Section "Device"
Identifier "Configured Video Device"
Option "AccelMethod" "exa"
EndSection
Then restart X and you should be able to enable desktop effects without a freeze.
Unfortunately, UXA acceleration continues not to work. If there's any information I can provide to figure this out, please let me know.
As a workaround, I've discovered that switching to EXA acceleration seems to work. To do that, open the file /etc/X11/xorg.conf and make sure you have a section that looks like:
Section "Device"
Identifier "Configured Video Device"
Option "AccelMethod" "exa"
EndSection
Then restart X and you should be able to enable desktop effects without a freeze.
Unfortunately, UXA acceleration continues not to work. If there's any information I can provide to figure this out, please let me know.