VNC framebuffer block artefacts on qemu-kvm-0.12.1.1

[Mark Cave-Ayland <mark.cave-ayland@siriusit.co.uk>]

Hi all,

Having just upgraded from kvm-85 to qemu-kvm-0.12.1.1 on one of our 
servers, I've noticed that I am seeing block artefacts when connecting 
using VNC to the graphical VGA console of a WinXP guest.

Looking at the VNC output, what I am seeing is that instead of updating 
some parts of the screen which require a redraw, they are just being 
replaced by light grey blocks of around 16x16 pixels. Generally, but not 
always, several of these blocks appear in a row. Moving the mouse over 
the relevant sections of the screen causes them to be redrawn correctly.

I've tried this using both the cirrus and vga drivers, switching between 
16/24/32 bit colour and also different resolutions and unfortunately the 
effect still remains :( Is there anything else I can do to help try and 
debug this? Again this is on an x86_64 Debian Lenny host with a 2.6.32.2 
kernel on Intel.


ATB,

Mark.

-- 
Mark Cave-Ayland - Senior Technical Architect
PostgreSQL - PostGIS
Sirius Corporation plc - control through freedom
http://www.siriusit.co.uk
t: +44 870 608 0063

Sirius Labs: http://www.siriusit.co.uk/labs