[Qemu-devel] Cirrus + "Desktop Effects" = Garbled screen

[Qemu-devel] Cirrus + "Desktop Effects" = Garbled screen

[Brian Wheeler]

[-- Attachment #1: Type: text/plain, Size: 702 bytes --]

I was playing with fedora 12 and trying to get the "Desktop Effects" to
work.  When I switch to it the screen appears as the attached
screenshot.  I've gotten the same results with moblin's default setup.

I grabbed the latest git and turned on debugging in cirrus for:

#define DEBUG_CIRRUS
#define DEBUG_BITBLT
#define DEBUG_VGA
#define DEBUG_VGA_REG

but nothing interesting is output (just the bitblts for the window
closing) when I hit the "gnome shell" radio button...so it may be a
guest issue.

The information is obviously there, but it looks like either the client
is writing it in the wrong format or the emulator is interpreting it
wrong. 

Any ideas on how to debug this?

Thanks!
Brian



[-- Attachment #2: Screenshot-QEMU (Fedora 12).png --]
[-- Type: image/png, Size: 110592 bytes --]

Re: [Qemu-devel] Cirrus + "Desktop Effects" = Garbled screen

[Reimar Döffinger]

On Tue, Aug 25, 2009 at 04:28:19PM -0400, Brian Wheeler wrote:
> The information is obviously there, but it looks like either the client
> is writing it in the wrong format or the emulator is interpreting it
> wrong.

Looks like it is writing 32 bit data into a 24 bit framebuffer.
I guess desktop effects uses software emulation OpenGL.
I'd suggest first checking if software OpenGL supports 24 bit
framebuffer, otherwise it can't work.
Next I'd check which format/bit depth the X server is trying to use.
Last you could try debugging the SDL stuff to see which format it
actually uses.
Last, you can try to hack sdl.c to force it to use a different
bit depth (note I don't know how well that works with cirrus or if
this actually works at all) by changing sdl_create_displaysurface,
probably line 183.
That's all I can think of (I'm new to qemu, so I probably lack some
details).

Greetings,
Reimar Döffinger