[virglrenderer-devel] Anyone see black screen when refreshing qemu window?

Gert Wollny gert.wollny at collabora.com
Tue Jul 24 19:10:24 UTC 2018

Am Dienstag, den 24.07.2018, 11:48 -0700 schrieb Lepton Wu:
> Hi,
> Here is a bug I met when running virlgl + qemu with my guest (Chrome
> OS). I've put a video here to show what I mean: https://youtu.be/yG-
> BbWHOwG4
> As you can see, when I moved around another application window, qemu
> will show black screen sometimes. 
I haven't seen it like this, but when I run virgl with the SDL backend
(which is required to get a GLES host context on the desktop linux)
resizing or moving to another virtual screen and back will result in a
black window with a simple X window manager (like backbox). I noticed
that with the gnome desktop inside the guest this didn't happen. 
I think there is a problem with when the desktop is redrawn, it isnot
always signalled. I even have a little script to force a redraw that I
can run from an ssh console. 

export DISPLAY=:0 
xrandr --output Virtual-1 --off 
xrandr --output Virtual-1 --auto 

Actually, I just noticed that when I turn off the compositing on my
desktop then it is worse. Movong the window or overlapping anather
window results in all black, and only with these commands above I can
bring it back. 

> This only happen when  running qemu with virgl option.
> Actually this could be a bug in qemu side, but just wondering, is
> this a known issue happening to everybody or just something
> specific to my setup.
I think it must be a SDL/qemu problem that it doesn't send the refresh
command properly. 


> Thanks!
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> virglrenderer-devel at lists.freedesktop.org
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