Slint performance problem with DumbBufferDisplay and LinuxFBDisplay

[fluolite]

In my project, the app window size is 480px*480px.
I run it in different backend.

1. Linux-x11 + winit opengl renderer, it can run 60fps.
2. Linuxkms + software renderer (LinuxFBDisplay), it can run 24fps->30fps.
3. Linuxkms + software renderer (DumbBufferDisplay), it only can run 12fps, and touch event can not responsive some times.

Is that is right？
DumbBufferDisplay performance should not be better than LinuxFBDisplay?
I'm really a little confused.
I hope to get some advice or help.
Thank you.

[ogoffart]

Maybe this is caused by #6951 ?

[fluolite]

Is that has been found and solved?
Should we see it in the next version 1.9?
It's so exciting!

[tronical]

That's very well possible, at least for 3. The fact that the software renderer performs worse than OpenGL rendering is probably expected (difference between 1 and 2), and 12 is half of 24, which is #6951.

[fluolite]

I have also noticed this iuuses too.
The fix code has been submitted to the master?
How can I get it and make a testing.

[tronical]

I've got a work-in-progress patch at https://github.com/slint-ui/slint/tree/simon/linuxkms-triple-buffer-gbm but unfortunately it doesn't cover DumbBufferDisplay yet.