Re: Tips for debugging GPU acceleration.

Alex Bennée

Thanks - that seems to do the trick.
I can't find where in the agl repo that is set. The recipe seems to be in:


but I can't see where the "transform=270" got added.

Visually it looks a lot nicer now although I could still do with
getting rid of the quite large AGL lower banner which is cropping out
the main display.

On Fri, 23 Oct 2020 at 13:32, Marius Vlad <> wrote:

On Fri, Oct 23, 2020 at 12:52:17PM +0100, Alex Bennée wrote:

Gerd Hoffmann <> writes:


[ 2.930300] [drm] virgl 3d acceleration not supported by host
Nope, not active.

-display gtk,show-cursor=on \
Needs -display gtk,gl=on for opengl support.
Awesome - even on TCG the display is now nice and snappy.

For bonus points:

The AGL panel display is rotated 90 degrees which is putting a bit of a
crink in my neck. Is their anyway to rotate the view port. I tried
inverting xres and yres but that didn't do anything.

The output is rotated, edit /etc/xdg/weston/weston.ini and comment out
transform ini entry from the Virtual-1 output section. Reboot, or
restart weston@display service. Note that the apps are optimized for

Enabling 3D with qemu might be something worth adding in the docs.

-device virtio-gpu-pci,virgl=true
virgl is silently turned off in case opengl support is not available.
Ideally virgl should be OnOffAuto not bool, but I fear changing that
now (and start throwing errors on virgl=on if opengl is not available)
will break stuff ...
At least a warn_report maybe?

take care,

Alex Bennée

Alex Bennée
KVM/QEMU Hacker for Linaro

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