Created attachment 206321 [details] journal log from the time of the gpu lockup. GPU is an AMD Kaveri: 1002:130f Happened when I started an application (way before the application actually showen) on KDE Plasma 5.5. The kernel version was 4.4.2 with an additional vblank fix applied (see [1]). Since I wasn't prepared for this and ssh wasn't activated and I couldn't save dmesg output. Instead I'll attach what I found in the journal. [1] https://bugs.freedesktop.org/show_bug.cgi?id=93746
Please attach the output of glxinfo and the Xorg log.
Created attachment 206381 [details] glxinfo
I forgot about Xorg log, sorry. Since only one old one is kept, it's gone already. Maybe logging to syslog/journal is a good idea ...
Today I ran into this again and got the Xorg log, but there doesn't seem to be anything interesting in it. Kernel is now 4.4.4. When the freeze occurs, I can still ssh into the system. Applications continue to run (i.e. I had a music player running), I could even reboot the system, although that seemed to take longer because X didn't like to shutdown (was markt as DSsl+ in ps aux).
Created attachment 207721 [details] Xorg.0.log
Any chance you could try if this also happens with LLVM 3.8 or even current SVN/Git? Does it always happen when starting a particular application?
I tried to build LLVM/clang scm, but it failed (have to check why and if I can get around that). I've had several freezes over the last few weeks (most of them when I bisected that other bug mentioned above (so could be unrelated), but only a few after staying on 4.4.x), but this one was the only one I could relate to a specific event, starting an application (thunderbird here). The other ones seemed to happen out of nowhere, so it could be that it was just coincidence that it happened when I started that application.
FWIW, right now it's better to try LLVM 3.8 than SVN/Git, because the latter will expose you to https://bugs.freedesktop.org/show_bug.cgi?id=94242 .
I will try to build llvm, but it could require me a few days since it's not yet provided by my distribution and I have to check the changes in the build system. BTW, I can usually ssh into the system. Is there any way I could gather more debug info when this happens?
During the last 2 weeks I switched between amdgpu and radeon a couple of times. What I noticed is that with radeon I do get lockups here and there, I think almost always (not 100% sure though) when a video is running. Both with xv and vdpau as video output. llvm is now 3.8. On amdgpu I haven't seen a lockup yet, except for a view when bisecting 4.4-rc2 or -rc3, but I guess that was a different problem which got fixed until the release.
Since I'm now exclusively using amdgpu and since that works very well for me, I didn't do much more tests with radeon and thus cannot tell if this is still present or not. Therefore closing the bug report.