limited screen resolution

[Benjamin Drung]

Binary package hint: kvm

I am using Ubuntu 9.04 as host and as guest. The Ubuntu 9.04 guest uses by default the cirrus driver and provides only a resolution of 800x600. After adding

Section "Monitor"
        HorizSync 30-140
        VertRefresh 50-160
        Option "DPMS" "on"
EndSection

to /etc/X11/xorg.conf the maximum resolution increased to 1152x864. The used monitor is a 24" TFT which provides a maximum resolution of 1920x1200.

ProblemType: Bug
Architecture: amd64
DistroRelease: Ubuntu 9.04
Package: kvm 1:84+dfsg-0ubuntu8
ProcEnviron:
 PATH=(custom, user)
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: kvm
Uname: Linux 2.6.28-11-generic x86_64

[Benjamin Drung (bdrung)]

Here is the Xorg log file from the guest.

[Dustin Kirkland  (kirkland)]

What is the kvm command line you're using to launch the guest?

:-Dustin

[Dustin Kirkland  (kirkland)]

I'm marking this confirmed, as it seems that Kees is seeing something like this too.

I have not reproduced the issue yet, though. I just installed the Jaunty Desktop and it defaults to 1024x768.

:-Dustin

[Benjamin Drung (bdrung)]

I am using "kvm -m 1024 -smp 2 image.qcow2" for launching the guest. I tried various other options, but without higher resolutions.

[Dustin Kirkland  (kirkland)]

Hi Benjamin-

What are the contents of your /etc/X11/xorg.conf in the guest?

:-Dustin

[Marc Deslauriers (mdeslaur)]

fyi, fedora's got a patch in their cirrus driver that detects the kvm pci id and sets the screen to 1024x768:

http://cvs.fedoraproject.org/viewvc/rpms/xorg-x11-drv-cirrus/devel/cirrus-1.2.0-qemu.patch?revision=1.2&view=markup

[Benjamin Drung (bdrung)]

Currently I have a problem with my BIOS and it is not possible to activate the virtualization support of the CPU. I used the default xorg.conf with the changes described in the bug description.

[Mike Hicks (hick0088)]

One problem is that the emulated Cirrus card apparently only has 4MB of video RAM, which effectively limits the 24/32-bit depth resolutions to 1152x864. You could probably go higher with 16-bit color instead.

I've been trying to use the alternate "-vga std" and "-vga vmware" display devices, which should both support higher resolutions, but haven't had much luck with them. The Ubuntu boot splash screens don't display in either mode, and the guest system appears to hang. They'll boot if I remove the "quiet splash" options from the kernel command line in GRUB, but I haven't had success in getting Xorg to load after getting to the login prompt.

I've had some success in getting the "-vga std" virtual adapter to work under QEMU (0.10.0-1ubuntu1), but haven't had it working with KVM (1:84+dfsg-0ubuntu11). I've let it boot up to the command prompt, then ran "sudo modprobe virtio_console" and then did "sudo /etc/init.d/gdm restart", and it worked once or twice. However, I've been trying to run on a x86_64/amd64 host with "-cpu core2duo" in both cases (using qemu-system-x86_64 for the QEMU guest).

[Theo Nolte (theo-nolte)]

This seems to be a general issue with the cirrus driver in the kernel. I found the following post in the qemu forum, which provides an xorg.conf for a 1200x900 resolution:
  http://qemu-forum.ipi.fi/viewtopic.php?f=10&t=4631

Regrettably I did not manage to get any higher. Using '-vga std' is no help either, because the ubuntu guest hangs on boot when trying this option.

[Dustin Kirkland  (kirkland)]

Thanks for finding that patch, Marc.

Bryce is working on getting this into our cirrus driver for Karmic, so I added a task for that package.

Also, I filed this bug against upstream QEMU. I can confirm that I'm having trouble with -vga (anything other than cirrus). These video modes should work as well. Hopefully Anthony can take a look. Thanks.

:-Dustin

[Bryce Harrington (bryce)]

Yeah, this solution is a bit hackish but should be fine. A more proper solution would be for kvm to more properly implement the virtual monitor, by providing a dummy EDID structure... this is covered already by bug 237164 and probably not something we're going to see soon, so for now we can fix this one using the fedora patch Marc found.

[Theo Nolte (theo-nolte)]

Thank you so much! You did a brilliant job! Works perfectly since this morning. No idea what fixed it, maybe it was kernel 2.6.31-10 or xserver-common.

Now the vesa-emulation (-vga std) works for me with karmic guest on karmic host and I can get any resolution I want including my native one. The xorg.conf I use on the guest is attached. If you want other resolutions just change 1680x1050 to whatever you want.

This only works for karmic guests. For 9.04 guests you still have to use the cirrus driver (-vga cirrus), which is limited to 1280x1024.

[Dustin Kirkland  (kirkland)]

I'm marking the kvm and xorg tasked "fix released", as I, too, can confirm that we now have much better resolutions at our disposal in Karmic.

I'm leaving the upstream QEMU task open, however, in that QEMU could (should?) provide a better EDID interface.

:-Dustin