Comment 43 for bug 1161371

I reinstalled Raring from a daily build in the hope that might fix things. It didn't: booting still usually, but not always, fails. To recap what I've said above, when I boot one of three things typically happens:

1. I'm left looking at a black screen with a mouse cursor on virtual terminal 7. No process has crashed.
2. The X server crashes, and the log file shows "no devices found"/"no screens found" errors.
3. The boot succeeds.

I compared the X server log in case 1 with the log after a successful boot and saw an interesting difference. In case 1, the log contains this:

[ 7.479] (II) intel(0): SNA initialized with no backend
[ 7.479] (==) intel(0): Backing store disabled
[ 7.479] (==) intel(0): Silken mouse enabled
[ 7.479] (II) intel(0): HW Cursor enabled
[ 7.479] (II) intel(0): RandR 1.2 enabled, ignore the following RandR disabled message.
[ 7.479] (==) intel(0): DPMS enabled
[ 7.480] (WW) intel(0): Textured video not supported on this hardware

For a successful boot, the corresponding lines look like this:

[ 7.404] (II) intel(0): SNA initialized with IvyBridge backend
[ 7.404] (==) intel(0): Backing store disabled
[ 7.405] (==) intel(0): Silken mouse enabled
[ 7.405] (II) intel(0): HW Cursor enabled
[ 7.405] (II) intel(0): RandR 1.2 enabled, ignore the following RandR disabled message.
[ 7.405] (==) intel(0): DPMS enabled