Hi, I have updated the BIOS of my Thinkpad to v1.24 and I have installed the Backport default kernel (6.3.0-lp154.4.g48306c1-default #1 SMP PREEMPT_DYNAMIC). With both things I have the first time a working HDMI port for an external monitor. But some parts of the desktop flashes permanently and produces GFX errors. So it seems the i915 device driver is still in an experimental phase for the device 4628 (from lspci: VGA compatible controller: Intel Corporation Alder Lake-UP3 GT2 [UHD Graphics] (rev 0c)). Where I can create a bug report (Intel, Lenovo, Suse, Kernel)? Should I better use an USB-C to HDMI converter?
If you haven’t yet tried it, try appending the kernel parameter i915.enable_psr=0 to the linu line in the Grub menu by striking the E key. https://wiki.archlinux.org/title/Intel_graphics has other options you might wish to try before reporting a bug.
Leap 15.5rc1 has either been announced as available, or is about to be. Release is due early June, which means it’s mostly done already. 15.5 really amounts to little more than hardware support additions to 15.4. Alder Lake support should be complete in it. If it’s not, developers need to know. IMO the best way forward would be to try 15.5 before thinking about reporting a 15.4 bug.
Before reporting a 15.4 bug I would try a newer Xorg version from repo https://download.opensuse.org/repositories/X11:/XOrg/openSUSE_Leap_15.4/. If it doesn’t help, then report an openSUSE bug on Xorg:
If it turns out to be a kernel bug rather than Xorg, the X devs will move it appropriately.