VNC resolution

Submitted by Isshou on Sun, 03/13/2011 - 15:50

Hello, just creating separated issue as you asked about built-in VNC screen size.

The size of VNC screen is fixed. For example I was installing Ubuntu 10.10 desktop and during installation there are dialogs that don't fit the screen. I was able to change it in the source file kvnc.cgi but maybe would be good to autodetect it if possible (not sure about this) or have there some check box with resolution to select from.

Status: 
Closed (fixed)

Comments

Submitted by JamieCameron on Sun, 03/13/2011 - 21:29

The size of the VNC window isn't really the important factor here - instead, you'd need a way to change the size of the virtual graphics card within KVM. Apparently the --std-vga command line option to KVM can be used to do this, but in my tests it didn't seem to help much.

Submitted by Isshou on Wed, 03/16/2011 - 12:53

I was searching what to do with "--std-vga" paremeter too and in "man kvm" I actually found that it should be used as "-vga std". I don't know if it can be used to force some resolution for built-in Cloudmin's VNC but it enabled the guest to run in higher resolution (currently up to 1600x1200).

Related to this option I have question - I tried to put "--std-vga" to Cloudmin configuration / KVM Settings and there is "Default additional command line options". But when I start KVM machine the "--std-vga" is not there. It doesn't work this way?

Submitted by JamieCameron on Wed, 03/16/2011 - 13:17

From my reading of the docs, --vga std is a replacement for --std-vga , and both do the same thing.

Unfortunately that field for setting default additional command line args is broken :-(

But as a work-around, you can edit the VM's file in /etc/webmin/servers and add / change the kvm_args line to :

kvm_args=--std-vga

In my tests, even with this Ubuntu was only running at the default 800x600 (or maybe 1024x768) resolution. I'd be interested to know if you get different results ..

Submitted by Isshou on Wed, 03/16/2011 - 14:55

I tried something now and got different results :) . By the way kvm_args works well.

First for Windows system - set "kvm_args=-vga std" is enough to have available resolutions up to 1600x1200 (Windows 7 tested).

Now for Linux. Without anything done there are resolutions 640x480, 800x600 and 1024x768. When I set "kvm_args=-vga std" I got only 640x480 and 800x600. Then I took a look around and found this (I am more familiar with Windows):

http://blog.bodhizazen.net/linux/how-to-improve-resolution-in-kvm/

and I made this xorg.conf:

Section "Device"
Identifier "Card0"
Driver "vesa"
BusID "PCI:0:2:0"
EndSection

Section "Monitor"
Identifier "Monitor0"
VendorName "Monitor Vendor"
ModelName "Monitor Model"
HorizSync 30-107
VertRefresh 48-120
EndSection

Section "Screen"
Identifier "Screen0"
Device "Card0"
Monitor "Monitor0"
SubSection "Display"
Viewport 0 0
Depth 24
Modes "1600x1200"
EndSubSection
EndSection

and still with "kvm_args=-vga std" my VM Ubuntu 10.10 was able to run with resolution up to 1600x1200 too.

And just for information, on this page

http://www.linux-kvm.com/content/using-high-resolution-graphics

somebody wrote that with qemu 0.9.1 kvm-84 it was possible to set even higher resolution but later it was restricted to 1600x1200.

Anyway... it probably doesn't solve the issue with VNC screen size during installation.

Submitted by JamieCameron on Wed, 03/16/2011 - 15:09

Ok, thanks for the info.

In the next Cloudmin release (5.4) I will add an option to enable use of high-res graphics mode for KVM instances.

Submitted by Issues on Wed, 03/30/2011 - 15:20

Automatically closed -- issue fixed for 2 weeks with no activity.