Quote:
Originally Posted by DiapDealer
It is my understanding that any of the proprietary Nvidia drivers after version 495.44 (which my drivers are way beyond) includes a GBM backend. Yet the webengine included in Qt6.9.0 automatically complains that "GBM isn't supported in my configuration" based on nothing but the vendor name "nvidia". *shrug*
See Peter Varga's comment here: https://bugreports.qt.io/browse/QTBUG-136160
No one's explanation for why this is being done satisfactorily explains to me why the behavior changed between 6.8 and 6.9. Qt suggests the change occurred in Qt6.6, yet Sigil worked just fine on my Arch machine with Qt6.6, 6.7, and 6.8. No idea why they decided to break video webengine rendering performance in 6.9 for millions of users. |
From what I understand, recent changes in Chrome changed how gpu interaction is done and removed a bunch of background code that supported various gpus (this happened back in Qt 6.3 or 6.5 timeframe). Since then, Qt has reintegrated that missing code and kept it working but it is becoming a major problem as that chromium code no longer exists in Google's tree and is no longer getting security fixes either.
Qt decided to try a new way to extract a gpu buffer's contents from the new chromium code and insert that into is own QtWebEngine. That required moving to native direct rendering on Windows, metal on macOS and then for linux/unix they tried to develop things for X and wayland and etc to do the same. This was built and improved on up through Qt 6.8.x but was changed in 6.9 to move solely to their new approach. And Qt 6.9.0 was the guinea pig target when all the extra old reintegrated chromium code went away and they rely completely on their new approach.
Needless to say it was quite rocky and lots of things have broken and Peter Varga of Qt is the one who seems to be trying to get fixes in place as soon as possible. At least unlike many Qt devs, he is very willing to help users debug issues and generate fixes. He did with my setup.
I hope/think Qt 6.9.1 should better handle Nvidia especially those that are not legacy and will support GBM but ... who knows. Linux and Nvidia have always had a rocky relationship but hopefully things will smooth out.
If your slowness has not gone away when Qt 6.9.1 is officially released, I would file a bug report with Qt directly, providing details about your specific setup and gpu or gpus, and turn on Qt debugging output and post it there asking for help.