PTB thinks I have hybrid graphics on Ubuntu 24.04.1-LTS

Hardware
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I’m trying to get my system off the ground with PTB. It’s a ubuntu 24.04.1 LTS desktop, with an AMD GPU (only default linux drivers as per documentation here) - Gigabyte 7900 GRE. I’ve been having trouble with every flip in (mostly otherwise successful) tests, resulting in warnings being thrown up that “flip X for window Y didn’t use pageflipping for flip”, directing me to the linux section of “help SyncTrouble”.

From there, I’m trying to use XOrgConfCreator (and later selector) to try to fix things. “This seems to be a hybrid graphics laptop” is what comes up - I can only imagine if my machine is registering like that, some things are being set up wrong. I don’t think my CPU even has integrated graphics - just checked, no it doesn’t - i9 13900KF, but I disabled anything in the BIOS relating to IGPUs anyway.

I have tried to soldier through with that process anyway, but no settings I choose change anything about those flip errors. In fact, the 30 bit framebuffer for 10 bpc, when I select that, makes matlab’s loading splash colour-distorted and matlab not launch properly until I delete the file (I am hoping to get 10 bpc still at some point). I don’t seem to get any option to change anything about triple buffering (which I expected from the text of SyncTrouble).

I use the xorg desktop on login as it seems like the desktop with the most minimal composition, which seems to be recommended. Any ideas about what might be happening here?

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Have you seen this thread? No pageflipping on Ubuntu 24.04-LTS with Ubuntu/Gnome desktop GUI

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Thanks - I hadn’t! Not sure how that didn’t show up in my searches. It does seem to make VBLSyncTest go better, though my own eventual stimuli are still having the same problem. Still, it’s progress!

And maybe I’ll do the same as them and just step down to ubuntu 22 ultimately.

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XOrgConfCreator misdetecting your machine as dual-gpu is a false positive. However, it should not have any negative side effect apart from creating some confusion on your side, iow. things should still work fine. I have updated the scripts detection heuristic to deal with some changes in Ubuntu 24.04-LTS and make this work more properly again. Will be part of a future PTB release…

The Ubuntu/Gnome desktop GUI hack should fix page flipping, as would switching to a different desktop environment like KDE or the simple/minimalistic XFCE-4.

Ubuntu 24.04 was only minimally tested so far, due to lack of financial funding by our unsupportive users. I think apart from the need for this page flipping hack on Ubuntu/Gnome, I also encountered failure of our Vulkan display backend to work, for which I also developed a fix already for a future PTB release.

For any further help from my side, PsychPaidSupportAndServices.