Created attachment 110204 [details]
Firefox froze for few seconds and then it unfroze and I saw a notification from KDE telling me that desktop effects were restarted due to graphics reset. After that, everything seems to work as expected.
dmesg showed me:
[drm] stuck on render ring
[drm] stuck on blitter ring
[drm] GPU crash dump saved to /sys/class/drm/card0/error
[drm] GPU hangs can indicate a bug anywhere in the entire gfx stack, including userspace.
[drm] Please file a _new_ bug report on bugs.freedesktop.org against DRI -> DRM/Intel
[drm] drm/i915 developers can then reassign to the right component if it's not a kernel issue.
[drm] The gpu crash dump is required to analyze gpu hangs, so please always attach it.
SandyBridge in Lenovo laptop
OS: Archlinux 64bit
kernel 3.14.25 LTS
desktop KDE 4.14.3
Created attachment 110205 [details]
Created attachment 110206 [details]
*** This bug has been marked as a duplicate of bug 54226 ***