Assertion '!modifiers.empty()' when running gamescope in embedded mode

[Erfboom]

Using the following:

• Intel UHD630
• 6.8.1-1-default linux kernel
• Opensuse Tumbleweed
• gamescope -W 2560 -H 1440 -r 120 -- moonlight in tty2 (embedded)

I receive Assertion '!modifiers.empty()' after a core dump. The program can be anything, not just moonlight.

When I run gamescope in nested mode, I can run things, but for moonlight specifically, once I activate a stream, I'll see a black frame in between every couple of good frames. If I use --expose-wayland, this will be reduced, but I'll trade it for choppiness in the stream on the native moonlight-qt, or smoothness with the AppImage variant but still the black frames.

If I run moonlight from terminal, no gamescope, the stream is as intended, smooth, no black frames.

EDIT: The flickering was caused by specifying the refresh rate in the gamescope command. Removing it causes the stream to be fine.

[rien]

I'm encountering a segfault as well on an Intel UHD620 - @Erfboom did you manage to work around this issue?

[Erfboom]

No, but I believe it's being worked on.

[jpgrego]

Same problem here, also with a HD620. Any news regarding this?

[repomansez]

Happening to me too, even when just launching gamescope by itself. UHD Graphics 620 on a ThinkPad T480

[2goodAP]

Yes, I too can reproduce this on NixOS with Intel GPU. I am using KDE Plasma 6.1.4. Also, the assertion failure only happens in nested mode. Everything works just fine for me under a separate tty.

I did some digging around and found this to be an issue for 3.15.x versions only. Nested mode works just fine for me up to commit 94271f3.

The 3.15.0 commit 28a4744, seems to have made some changes to DRM formats for composited outputs. That seems to be a possible cause for the assertion failure in nested mode only.