Comment 7 for bug 946899

I am suffering this bug and similar ones related to what seems to be a regression in kernel.

I have 3 similar systems with the following configurations:

1- Work PC, with Precise updated from Oneiric since Beta 2, i5-2400. Does not seems to be affected by the bug.

2- Main home PC, with Precise updated from Oneiric since Beta 2, i5-2500K. The bug and completely system hangs occurs so often that it is nearly unusable. This happens also with the latest mainline kernel 3.4-rc4-precise (http://kernel.ubuntu.com/~kernel-ppa/mainline/). However, if I start with kernel 3.0.17 from Oneiric, the bug does not appear. I am working with it for nearly two days without a single hang. So, this may be a workaround.

3- Same home PC, fresh Ubuntu Precise distribution installed in a clean partition, same i5-2500K. I use it as a test platform. The bug has occured, and the dmesg attached belongs to this clean system. Nothing more is installed from default, safe the precise updates.

The bug produces several 2-3 seconds black screen and back to normal for 10-20 seconds, in sequence, normally followed by a completely desktop hang which requires a full reset. Sometimes, the hang does not occur, but all windows decorations and the unity bar dissapears (like the window manager is dead).

The bug appears randomly, but more often if switching from desktop spaces, and with firefox navigator open.