[Spice-devel] qxl-vga.vgamem_mb and large monitors

[David Mansfield]

Hi All,

We (4 of us in my company) have been very happy with spice over the last 
year or so running with dual 1920x1200 monitors, for which 
qxl-vga.vgamem_mb always needed to be set to 32 (default is 16) or 
Xorg-qxl doesn't get enough video ram.  I even bumped it to 64MB and we 
can run a 3940x2160 and a 1920x1200 just fine.

This is set it libvirt domain xml like this:

  <qemu:commandline>
     <qemu:arg value='-global'/>
     <qemu:arg value='qxl-vga.vgamem_mb=32'/>
   </qemu:commandline>

This is a Centos 7.1 host and Fedora 22 guest

However, I just got a qemu-kvm update from the ovirt repository to 
version qemu-kvm-ev-2.1.2-23.el7_1.3.1.x86_64, from the previous version 
qemu-kvm-rhev-1.5.3-86.el7.1.x86_64, and now I get this error in Xorg.log:

[   321.154] (EE) qxl(0): failed to set mode: Invalid argument(II) 
qxl(0): Allocate new frame buffer 3840x1200 stride
[   332.363] (EE) qxl(0): failed to set mode: Invalid argument

Whereas at slightly lower resolution:

[   309.808] (II) qxl(0): Allocate new frame buffer 3840x1080 stride

Works fine.  Now:

3840 x 1080 x 4 = 16588800 < 16 * 1024 * 1024 = 16777216

but

3840 x 1200 x 4 = 18432000 > 16 * 1024 * 1024 = 16777216

So my conclusion is that the command line argument isn't working anymore 
and the 16MB default is back in place.

Has qemu/libvirt changed somehow making this old syntax invalid?

-- 
Thanks,
David Mansfield
Cobite, INC.