Re: [Qemu-devel] [PULL 3/3] cirrus: Fix host CPU blits

[Benjamin Herrenschmidt]

On Mon, 2014-07-14 at 09:24 +0200, Peter Lieven wrote:
> it seems you have digged into the cirrus code recently. Have you an idea how 
> to
> fix the issue with the graphics corruption for cirrus vga and recent X Server 
> versions?
> 
> E.g. take an Ubuntu 14.04 Desktop CD, boot it into live mode and open 
> terminal.
> 
> I have tried to debug it a little, but I have no clue how to solve this. I 
> tried to get
> hands on a real hardware Cirrus Logic Graphics card and test if this happens 
> there as well,
> but I had no chance to get one.

I *think* it is a X server side bug. They broke 24bpp packed pixel
format. I've seen patches submitted to the Xorg list fairly recently by
somebody from canonical.

You can test by creating an xorg.conf to force the display to 16bpp
instead of 24 and see if that helps.

Cheers,
Ben.