Might be a duplicate of bug #327844 - can you please verify that the problem goes away when disabling compiz and not using any 3d/xvideo features? Can you please attach your Xorg.*.log* and check if it contains something like this:
Ring at virtual 0x7f7e27098000 head 0x19624 tail 0xf0 count 6835
Ring at virtual 0x7f7e27098000 head 0x19624 tail 0xf0 count 6835
... [repeats several times]...
Ring at virtual 0x7f7e27098000 head 0x19624 tail 0xf0 count 6835
Ring end
Might be a duplicate of bug #327844 - can you please verify that the problem goes away when disabling compiz and not using any 3d/xvideo features? Can you please attach your Xorg.*.log* and check if it contains something like this:
Ring at virtual 0x7f7e27098000 head 0x19624 tail 0xf0 count 6835
Ring at virtual 0x7f7e27098000 head 0x19624 tail 0xf0 count 6835
... [repeats several times]...
Ring at virtual 0x7f7e27098000 head 0x19624 tail 0xf0 count 6835
Ring end