Weston-eglstream black screen

I haven’t tried weston-eglstream under nvidia proprietary in about two years, but it was working at the time. Just no acceleration when using X11 gtk2 apps like Steam. This has changed with a mesa patch from Adam Jackson that allows acceleration of X11 apps and nvidia blob.

With that recent mesa patch (WIP: GLX Delay (accelerated GLX for Xwayland with the NVIDIA driver) (!6429) · Merge requests · Mesa / mesa · GitLab), I wanted to give nvidia+wayland a shot again. When launching weston-eglstream 9.0.0 using 455.28 drivers, you are presented with a black screen, and have to switch tty to force close weston.

I made a post about this on the weston gitlab, and they redirected me to come here, as they said it’s a bug on your end.

He specifically mentions this line in the log.

“queueing pageflip failed: Device or resource busy”

Here is the log.

https://gitlab.freedesktop.org/wayland/weston/uploads/5b64fe1bfd113b9d8681390513aac9a5/weston.log

Does this happen every time ? I’ve seen that message appear after a previous crash or something leaves the KMS system in a bad state, which can interfere with subsequent attempts to start Weston. Generally a reboot resolves the issue.

I found out what it was. It was an NVIDIA environment variable I was using.

export __GL_SYNC_TO_VBLANK=0

Forcing VSync off will make weston black screen. Is VSync required for a Wayland compositor?

That’s interesting. In theory I think it should be possible for a Wayland compositor to run without vsync, although I’m not sure about the semantics of tearing page flips in DRM-KMS. It’s also entirely possible that this is the result of some bug in our modesetting driver. I’ll look into it a bit more. Thanks for narrowing down the issue, though.

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