vesa driver reports many modes, but only allows a few

Pat Kane pekane52 at
Mon Mar 1 08:21:35 PST 2010

To get higherVMware X display  resolutions I had to add these to
the  xorg.conf file inside my virtual machine:

   Section "Monitor"
       Identifier   "Monitor0"
       VendorName   "Monitor Vendor"
       ModelName    "Monitor Model"
       HorizSync    10 - 300
       VertRefresh  10 - 200

 SubSection "Display"
       Viewport   0 0
       Depth     24
       Modes     "1024x768"

Does that help?


On Mon, Mar 1, 2010 at 1:28 AM, Ross Boylan <ross at> wrote:
> Could anyone explain to me what the attached log means?
> X 7.5 detects a rich array of BIOS modes, but then runs through a list
> of modes and says "no mode of this name".  Should it be using something
> like "104" or  "104 (1024x768)" instead of, e.g., "1024x768"?  Then X
> tries a less strict probe, and rejects all but a couple of
> low-resolution modes with "hsync out of range".  I have no xorg.conf
> file.
> X is running inside a VM, to which I'm connected via vnc.  The VM is
> running Debian squeeze (testing).  When it starts up, the boot screen
> appears to be 640x480.  If I launch an X session, I get 800x600.  I
> would like higher resolutions in both terminal and X mode.
> The host runs qemu-kvm-0.12.2, compiled from source on Debian lenny
> (stable), amd64 architecture (Xeon).  The VM is also amd64, with
> multiple CPU's.
> I don't need to do anything special to get the tablet device recognized,
> which is nice improvement over X 7.3 on Debian Lenny.  But something is
> going wrong with the video.  Other bugs on the net suggest that the
> virtual display adapter is not advertising its modes properly.
> Consistent with that, the DDC does not seem to work; there is a message
> "VESA VBE DDC not supported".  However, the log lists many video modes;
> it appears X is getting the information it needs.
> I have tried various xorg.conf's, but have gotten nowhere--apparently if I
> define one section I need to define all the others.  The logs don't seem
> to have any modelines, ruling out the simple solution given in the FAQ.
> I launch with
> sudo vdeq bin/qemu-system-x86_64 -net
> nic,vlan=1,macaddr=52:54:a0:16:01:01 \
>    -net vde,vlan=1,sock=/var/run/vde2/tap0.ctl \
>    -boot c \
>    -vga std -vnc localhost:7 -usbdevice tablet \
>    -name Squeeze00 \
>    -hda /dev/turtle/Squeeze00 \
>    -soundhw es1370 -m 1G -smp 4
> Of course, I'd also welcome help with the virtual machine, but I only
> came to this list for help on the X part.  Why are video modes being
> detected but not used?  Is there an xorg.conf I can specify that will
> work around the problem?
> Thanks.
> Ross Boylan
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> xorg at

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