[X2Go-User] x2goagent segfaulting on client connect

[Ulrich Sibiller]

On Wed, Oct 20, 2021 at 2:48 AM Eric Shell <eshell at ucsc.edu> wrote:
>
> I unfortunately require the proprietary nvidia driver as this system, a GPU processing host, runs a few pieces of CUDA software. My other requirement is the ability to render WebGL content in Firefox for use with one of the tools.

Unfortunately I have used such a setup.

> The yum history is there - what I should have said is that I do not understand which packages might be involved. There was a kernel update after which I had to reinstall the NVIDIA drivers (from the .run file). After doing so, I found I could not render WebGL in Firefox (running in an X2Go MATE desktop session). I found that my x2go sessions were using the OpenGL Mesa GLX Indirect renderer, as reported by glxinfo, and believed that to be the cause of the WebGL problem since it requires direct rendering and a newer version of OpenGL than the Mesa GLX Indirect renderer supports. This caused me to believe I needed to render OpenGL with the nvidia driver.

Did you reinstall the same nvidia drivers or a newer version?

IIRC there once was the necessity to chmod /dev/nvidia or similar to
make it available to all users. Not sure if that's still required.

> I switched to the ELRepo kmod-nvidia package which produced the x2goagent errors, likely because Xorg was running with the nvidia driver. That's when I made my original post.
>
> I've subsequently replaced the ELRepo driver with the NVIDIA driver from the .run file again. Now the GPUs are accessible and I can connect to X2Go but WebGL still doesn't function. Xorg is running with the nouveau driver according to Xorg.0.log and glxinfo reports "direct rendering: No". The Firefox about:support page shows errors like:

Just to be sure: are you connecting to the local X server (a so called
shadow session) or are you starting a NEW mate desktop in addition to
X server?

> WebGL creation failed:
> * Refused to create native OpenGL context because of blacklist entry: FEATURE_FAILURE_OPENGL_1
> * Exhausted GL driver options.
>
> Running "__GLX_VENDOR_LIBRARY_NAME=mesa LIBGL_ALWAYS_SOFTWARE=1 firefox" didn't get WebGL working, either, but did change the about:support output:
>
> WebGL creation failed:
> * Refused to create native OpenGL context because of blacklist entry: FEATURE_FAILURE_GLXTEST_FAILED
> * Exhausted GL driver options.

Does this call work with glxinfo/glxgears?

> Any idea how I can get WebGL rendered in an X2Go session again? I would assume that there wasn't a solution using X2Go if I hadn't used it successfully myself mere days ago. I intend not to use VNC if at all possible.

I am a bit puzzled about that blacklist entry. Maybe that is
modifiable in about:config. I have checked my firefox88 and it does
NOT seem to have this blacklist entry in about:config.

Also check/disable the hardware acceleration setting in firefox.

Uli