On a Sandy Bridge i5 Dell Latitude e6420 laptop with Intel HD 4000 integrated graphics. On 3.5.0-26-generic I experienced GPU hangs once or twice an hour (fixed themselves after a few seconds) and full lockups 2 to 5 times per day, depending on what I was doing (have to hard reboot the machine to recover). Having firefox open seemed to be a risk factor, and if FF had loaded flashplayer, I expected a full lockup at any moment.
This decreased the frequency and severity of lockups/crashes, but they were still there. Upon further investigation, I found this bug to be the actual issue (my syslog showing the same 3 lines as the others in this thread), and have reverted to 3.5.0-25-generic and have been running without any issues for a day or two now. I still have i915-semaphores=0 in my grub boot options but don't think I still need that...
Just some further confirmation of this issue.
On a Sandy Bridge i5 Dell Latitude e6420 laptop with Intel HD 4000 integrated graphics. On 3.5.0-26-generic I experienced GPU hangs once or twice an hour (fixed themselves after a few seconds) and full lockups 2 to 5 times per day, depending on what I was doing (have to hard reboot the machine to recover). Having firefox open seemed to be a risk factor, and if FF had loaded flashplayer, I expected a full lockup at any moment.
As described in the following bug, which is a similar issue... https:/ /bugs.launchpad .net/ubuntu/ +source/ xserver- xorg-video- intel/+ bug/1041790 ... I added the following to my /etc/default/grub options:
i915.semaphores=0
This decreased the frequency and severity of lockups/crashes, but they were still there. Upon further investigation, I found this bug to be the actual issue (my syslog showing the same 3 lines as the others in this thread), and have reverted to 3.5.0-25-generic and have been running without any issues for a day or two now. I still have i915-semaphores=0 in my grub boot options but don't think I still need that...