Virtualized accelerated 3D is complicated

3D acceleration in guests is not really perfectly stable yet…

Filing bugs

Bugzilla is a tiny bit faster today than it was yesterday.

Filed a bug regarding the lack of a tablet for Ubuntu or Mint guests.

Bumped this bug about shipping spice-vdagent on the install ISO, reported by Christophe Fergeau. Also added a bug to suggest that spice-vdagent be actually installed in guests, at least if the video is QXL, which is how virt-manager guests are configured by default.

Trying to capture yesterday’s bugs

I wanted to do a video grab of the various mangled screens I had seen yesterday in order to file a bug report, or attach it to some existing report if there is one.

The problem is that the issue no longer looks similar to what I saw yesterday. Worse is the fact that Tao3D no longer works at all in my guest. Even the most basic GL program, glxgears, does not work. So something was broken, either because I changed the guest resolution, or for some other reason.

Trying several variations, like changing the resolution, using Xorg. In that specific case, using Xorg actually makes things worse, since the Terminal does not even show up anymore…

Screen Shot 2017-02-16 at 13.52.08.png

I may be wrong, but my theory is that in Wayland, the compositor does its job correctly without using GL, whereas in Xorg, the compositor is using GL. But I may be wrong.

I tried to apply the two virt-xml commands again, to see if somehow the configuration had been damaged:

virt-xml fedora25 --confirm --edit --video clearxml=yes,model=virtio,accel3d=yes
virt-xml fedora25 --confirm --edit --graphics clearxml=yes,type=spice,gl=on,listen=none

The results are so spectacularly bad relative to what I had last Friday that I thought I might mis-remember and not be looking at the right VM. But the virt-xml commands were still in my command history.

Why qemu

Switching more VMs to accelerated 3D

Having had some success with the Fedora 25 VM on Big, even if temporarily, prompted me to convert the VMs on Muse to the same configuration. The Fedora 25 VM displayed glxgears successfully. This is before system update, so maybe there is something in the recently updated packages that causes the problem?

The Linux Mint distribution has this nice feature that it tells you when it’s using software for 3D rendering. Curiously, it does not seems to be able to detect a virtIO card by itself.

Spice for Mac

Not as much progress as I had hoped. No response to my bug report so far. I removed all the warnings, and the process still crashes.


Author: Christophe de Dinechin

I try to change the world, but that's work in progress. If you want to know me, google "Christophe de Dinechin". Keywords: concept programming, virtualization, OS design, programming languages, video games, 3D, modern physics. Some stuff I did that I'm proud of: the first "true" 3D game for the PC, HP's big iron virtualization, real-time test systems for car electronics, some of the best games for the HP48 calculator, a theory of physics that makes sense (at least to me).

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