Comment 33 for bug 136529

I've been experiencing the same on and off. Quite annoying. Looking at my xorg.conf I had the 'i810' driver for my Toshiba A200, which has an Intel 945GM chipset. I changed it to the 'intel' driver. The video board is detected correctly:

(II) intel: Driver for Intel Integrated Graphics Chipsets: i810,
        i810-dc100, i810e, i815, i830M, 845G, 852GM/855GM, 865G, 915G,
        E7221 (i915), 915GM, 945G, 945GM, 945GME, 965G, 965G, 965Q, 946GZ,
        965GM, 965GME/GLE, G33, Q35, Q33
(II) Primary Device is: PCI 00:02:0
(WW) intel: No matching Device section for instance (BusID PCI:0:2:1) found
(--) Chipset 945GM found

And after this, I don't seem to have any problems. I've also untertaken a radical cleansing of the xserver-xorg packages loaded on my machine.