Comment 163 for bug 256142

I have this problem as well on a Dell Latitude D620. Lot's of buffer underuns, and dual display with an external VGA is unusable - the external VGA keeps on flicking on and off.

root@psll09551:/var/log# dpkg -l | grep -i intel
rc 915resolution 0.5.3-1ubuntu1 resolution modification tool for Intel graphic chipset
ii wvdial 1.60.1+nmu2 PPP dialer with built-in intelligence
ii xserver-xorg-video-i810 2:2.4.1-1ubuntu10 X.Org X server -- Intel i8xx, i9xx display driver
ii xserver-xorg-video-intel 2:2.4.1-1ubuntu10 X.Org X server -- Intel i8xx, i9xx display driver

lspci -vnn:
00:02.0 VGA compatible controller [0300]: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller [8086:27a2] (rev 03)
        Subsystem: Dell Device [1028:01c2]
        Flags: bus master, fast devsel, latency 0, IRQ 16
        Memory at eff00000 (32-bit, non-prefetchable) [size=512K]
        I/O ports at eff8 [size=8]
        Memory at d0000000 (32-bit, prefetchable) [size=256M]
        Memory at efec0000 (32-bit, non-prefetchable) [size=256K]
        Capabilities: [90] Message Signalled Interrupts: Mask- 64bit- Queue=0/0 Enable-
        Capabilities: [d0] Power Management version 2
        Kernel modules: intelfb

root@psll09551:/var/log# uname -a
Linux psll09551 2.6.27-7-generic #1 SMP Fri Oct 24 06:42:44 UTC 2008 i686 GNU/Linux

Xorg.conf:
Section "Device"
        Identifier "Configured Video Device"
EndSection

Section "Monitor"
        Identifier "Configured Monitor"
EndSection

Section "Screen"
        Identifier "Default Screen"
        Monitor "Configured Monitor"
        Device "Configured Video Device"
Subsection "Display"
          Depth 24
          Virtual 1440 1924
        EndSubSection

EndSection

When running just on the panel display, it works OK ish, although some of the desktop effects are very sluggish, I'm running KDE.