I don't do an awful lot with videos, but I have lately noticed that gmplayer
doesn't re-enable the Display Power Management function of xscreensaver.
It used to be that gmplayer would turn off xscreeensaver completely for the
duration of the video and then put everything back to normal afterward.
Now, it seems to turn xscreensaver off for the duration of the video and
re-enable it afterward, but the Display Power Management function doesn't
return. So after playing a video I get my regular rotating selection of
xscreensaver demos, but my screen never blanks or turns itself off like it does
before I play a video.