Created attachment 103777 [details]
output of Xorg.0.log during uvd-test with DVD watching in fluxbox via smplayer

mark the "extra" explicitely set settings:

[   253.915] (**) RADEON(0): Option "EnablePageFlip" "off"
[   253.915] (**) RADEON(0): Option "ColorTiling" "on"
[   253.915] (**) RADEON(0): Option "AccelMethod" "Glamor"
[   253.915] (**) RADEON(0): Option "EXAVSync" "off"
[   253.915] (**) RADEON(0): Option "EXAPixmaps" "on"
[   253.915] (**) RADEON(0): Option "SwapbuffersWait" "on"

I read about commits from 3.14 to 3.16-rc* that mentioned pageflipping changes
but disabling that didn't make a change


*before* watching the DVD

I did another test

and accidentally watched a short portion of a HTML video on youtube with
chromium (actually only had intended to read lkml, but there was a reference
link and didn't mention that it was a video /facepalm), did some browsing, had
gnote running (and some more which I currently don't remember)

adobe flash was explicitely turned *off* via about:plugins

and X hardlocked while playing music (and mp3, via audacious) & browsing via
chromium


so at least in my case more and more signs seem to lead towards bug 81644
(https://bugs.freedesktop.org/show_bug.cgi?id=81644) and that chromium + html
video; or chromium and all sorts of video (vdpau doesn't apply here ?!)
triggers instability & (hard)locks