Cannot launch under wayland : Qt platform problem

[yrogge]

Expected Behaviour

Normal application launch, as worked "before" last system update.

Actual Behaviour

Freeze when launching (see log attached)

Steps to reproduce

Simply type "Stellarium" in terminal

System

• Stellarium version: 24.3.0-upstream1.1~ubuntu24.10.1
• Operating system: Ubuntu 24.10 (oracular) - Wayland display server (but same under XWayland)
• Graphics Card: Intel UHD Graphics (integrated)
• Screen type (if applicable): Lenovo Thinkbook Integrated (1920*1200, 60Hz)

Logfile

See attachments Terminal output: Stellarium Log.txt Log file: log.txt

[gzotti]

Reads like a driver setup problem to me.

[10110111]

Does any other Qt6-based app work? The following hints that the problem may be quite general:

QEGLPlatformContext: Failed to create context: 3009

Also, do you have a discrete GPU installed, possibly in an NVIDIA Optimus-like way?

[yrogge]

I'm not using any NVIDIA driver. I tried to resintall avery Qt6 stuff, but still same behavior. The way to bypass is

• either define QT_QPA_PLATFORM=xcb
• or to launch with "stellarium -platform xcb" Clearly, the problem is related to Wayland

[10110111]

You should report this to your distro maintainers, because this looks like a breakage of Wayland OpenGL support for all Qt6 apps.

[yrogge]

OK. I'll do. Thank you.

[alex-w]

You should report this to your distro maintainers, because this looks like a breakage of Wayland OpenGL support for all Qt6 apps.

The package is from our PPA and standard package may have differences

[alex-w]

Yep, standard packages in Ubuntu are Qt5-based

[10110111]

The package is from our PPA and standard package may have differences

In any case, the messages from Qt indicate a serious problem with OpenGL support. Or is Qt6 also provided by the PPA?

[alex-w]

The package is from our PPA and standard package may have differences

In any case, the messages from Qt indicate a serious problem with OpenGL support. Or is Qt6 also provided by the PPA?

No, we’re using qt packages from standard repository

[10110111]

No, we’re using qt packages from standard repository

So then indeed, it looks like the standard Qt6 packages are broken.

[gzotti]

Can we just add that environment variable to the startup? Or detect the necessity to do so first? (Is there a system configuration where you won't set xcb?)

[10110111]

Can we just add that environment variable to the startup?

We shouldn't try to work around all possible broken setups.

[yrogge]

I agree. Ubuntu does not even initialize the QT_QPA_PLATFORM variable (to value "wayland" normally) for Qt environments. If needed, it can be done in the .profile fille at session startup, but selecting "xcb" for all apps would be incoherent. Hopefully, "Open with QPA platform XCB" is one of the predefined option of the .desktop file used to launch Stellarium.

[gzotti]

I did not mean to set xcb globally. But just as we can set some OpenGL variable to ANGLE or SOFTWARE(?) for Windows, we could set another envvar to xcb on Linux, if needed. Is there a way to automatically detect if it's needed?

[10110111]

It seems to me that you are rushing to insert kludges for issues that may well be solved relatively soon by Ubuntu maintainers (assuming the OP has reported it there).

Such things should work out of the box, whether on X11 or on Wayland, and I suppose they used to work before the upgrade. It's just the upgrade that broke them, and, if I understood the OP correctly, it was a system upgrade, not a Stellarium upgrade. If Qt can't figure out that it's on Wayland, or that it should use EGL, or whatever else, there's something broken, and it should be sorted out in the distro, rather than getting worked around by the apps.

[gzotti]

I happily leave the actual 5-minute fix to those affected.

[alex-w]

The kludge for choosing XCB is included already in desktop file (it was added a long time ago) ;)

[yrogge]

Bug has been reported to Ubuntu/Debian Qt6 developpers https://bugs.launchpad.net/ubuntu/+source/qt6-base/+bug/2086676