Stalls in display- and window updates with kernel 6.8.4

[eselarm]

I upgraded from my own-compiled Armbian kernel 6.8.0-rc5 to 6.8.4 and there are now very annoying stall when for example I drag a KDE Konsole window.

Also when I play a 1080p50 HEVC video, as  son as a move the mouse, the whole video stalls.

 

Besides 6.8.0-rc5, the normal apt provide 6.8.1-edge-rockchip-rk3588 also works OK.  6.8.5 has the same issue as 6.8.4.

As indicated, I use KDE, X11, compositor disabled. Enabled makes no difference. OS base is Armbian Bookworm, but I have also used kernels 6.8.1 and 6.8.4 with a rootfs copied from an RaspberryPiOS and Opensuse-Tumbleweed. RPiOs is also Debian Bookworm, Tumbleweed is latest, KDE6. So it is not KDE6. KDE Wayland leaves black screen still (doesn't work), but that is not a showstopper.

 

Is anyone else experiencing the same?

 

PS: I run mainline as the vendor kernel 6.1.43 fails on running KVM (some tag of the Cortex-A55 is unknown) so qemu-KVM don't work/start and running VMs is a key use-case I bought the NanoPi-R6C for.

[eselarm]

An update to this topic:

All newer mainline kernels (latest I have tested 6.10.0-rc3-edge-rockchip-rk3588) have the same problem as the 6.8.4 one.

Change is that KVM now works with vendor kernel 6.1.75-vendor-rk35xx and default libvirt that comes with Debian12; it fails with newer libvirt.
 

[eselarm]

Another update, basically marking this topic as obsolete (concerning myself, my use-cases), is that KDE worked well when using the KDE neon build based on ubuntu22 image for NanoPi-R6C.

I won't try any further with KDE(Wayland)+bookworm+NanoPi-R6C. X11 works, but I use headless/CLI mostly.

There is also now an ubuntu24 based image available with 6.12 mainline kernel, so if I want to use desktop again I will use that and likely merge my bookworm server-oriented functionality into that.

[eselarm]

Maybe interesting to mention, I cleaned-up and reorganized various partitions and root filesystems. I have some simple multi-boot method, so I keep 4 OSses up to date always running the the latest rk3588 mainline kernel from Armbian repo (or compiled locally). Updates only done via ssh or serial serial console, but as KDEneon build based on ubuntu24 worked great on my new Rock3a (just cheapest 2GB variant), I thought let me connect HDMI to my NanoPi-R6C and see what Tumbleweed does with 6.12.y rk3588 mainline kernel. To my surprise and great pleasure it worked super fast!. Automatically Wayland selected. Just shaking a konsole terminal window with my mouse says enough in a blink of an eye. Great GPU acceleration. I use this distro also on my laptop (well 2 decades more or less) so great that the Armbian kernel can run it on RK3588. Don't really need GUI on NanoPi-R6C, but great as backup/alternative for old fat power hungry Intel PCs if needed.