Can't change screen brightness. Stuck at very dim display.

Hello there, I wonder if you could help me please. Yesterday I installed OpenSUSE Tumbleweed on a Lenovo IdeaPad Flex 15D with an AMD A6 APU (with Radeon HD 8400 graphics processor) I checked the kernel modules available for this card and the one in use is ‘radeon’ but ‘amdgpu’ is also available. Now I have been trying to tinker and follow some guides and recommendations but didn’t solve my issue so far. I tried to force it to work with ‘amdgpu’ instead of ‘radeon’ and would fail to boot to the desktop. Reverted back to ‘radeon’ and it went back to how it was.
The brightness keys on the keyboard don’t do anything, dragging the brightness slider in the applet menu doesn’t do anything at all. I just don’t know anymore what else I could do. I don’t know how to tell whether it’s just an unfortunate buggy kernel that I have in this snapshot (in which case I’m happy to wait for a patched update soon) or if there’s really something faulty somewhere else in the system that won’t be fixed with an update and requires manual intervention…
Thank you for your attention and I hope someone can help me with this. It’s quite annoying…

Ok, after noticing this affecting my previously perfectly functioning Lenovo ThinkPad, I thought this had to be a bug, the chances of having the same issue on 2 separate devices is rather thin really. Tested a BTRFS snapshot of the previous kernel version and it worked again like a charm, so rolled back to that snapshot and I just determined that the latest kernel version at the time of writing this, is just buggy (5.18.12-1-default).

Well, that is rather hard proof then. I assume this is worth a bug report (if you want it fixed).

For information: https://en.opensuse.org/openSUSE:Submitting_bug_reports
The bugzilla https://bugzilla.opensuse.org/index.cgi (same username/password as here).

And please post a link to the bug-report here in a post, so others can follow what happens, or add information when they experience the same.

Yes, thank you, I appreciate it. However I managed to downgrade the kernel version from an archive of openSUSE Tumbleweed repos from a few days ago, but it still didn’t work on this laptop (it worked on my own but not on this one). Mind you though, it probably is due to some other packages involved as well that are not included in the kernel itself (like additional firmware packages or some other stuff that I didn’t bother installing either). I really hope that an update in a few days/weeks time is going to fix this annoyance. I am open for more tips and things to try in the meantime anyway. But will look into submitting a bug report. Cheers

Link to bug report: https://bugzilla.opensuse.org/show_bug.cgi?id=1202125

For anyone else reading this, the issue is actually with polkit separating the pkexec, but not marking it as a dependency. Installing pkexec and rebooting solved the issue for me.