[CentOS-virt] Video resolution for CentOS guest

Tue Feb 24 04:11:06 UTC 2015
Robert Nichols <rnicholsNOSPAM at comcast.net>

Would someone please point me to some reasonably current instructions
for getting greater than 1024x768 video resolution for a CentOS 6
guest on a CentOS 6 KVM/qemu host?  When I search online I find stuff
from 2009 and 2010 saying, "For details see ...," and linking to a URL
that no longer exists, or pages that say, "You need to switch from VNC
to Spice," and giving a long list of out-of-date instructions for doing
so.  (With virt-manager it takes 2 clicks to do that.  Of course it
doesn't help -- still maxes out at 1024x768.)

I've found that I can just append "vga=0x380" to the kernel command
line and see Plymouth come up with the full graphical boot screen in
the correct 1440x900 resolution, but as soon as gdm starts up, the
display scrambles.  I find suggestions to generate an xorg.conf file,
but no mention of what to put in it.  I can run "Xorg -configure",
but the resulting file contains nothing about video modes, so it's
not apparent what needs to be added.

I find it particularly annoying that a Windows 7 guest can set any
resolution I want up to 2560x1600, but a Linux guest can't go higher
than 1024x768.

Bob Nichols     "NOSPAM" is really part of my email address.
                 Do NOT delete it.