I did install on my custom desktop PC OpenSUSE Tumbleweed KDE. After installation I arrive on GRUB and enter my encryption password once (I had trouble because the keyboard configuration was not the same as in OpenSUSE setup but now I know the key blindly to pass it), then I enter again my encryption password into OpenSUSE (this time with proper keyboard layout choose during setup) and finally I see the desktop for like 3 to 5sec maybe and then I have a black screen and the computer reboot eventually. It’s always the same each time I try.
It might not be related to OpenSUSE specifically as I had the same issue with another Linux booting on a LIVE USB drive (Manjaro, also with KDE), but still the same PC works fine for years on Windows 10.
CPU is AMD 5600X, GPU AMD R9 390X (quite old but still doing the job is these difficult time, I heard they was some issue in the past with R9 290 GPU on Linux but it should be solved and not sure the 390X is/was affected as well). I have Windows 10 with Bitlocker on the main SSD M2 NVME, OpenSUSE on a second SSD SATA, I have disabled secure boot as it was posing problem to boot some LIVE USB drive. I have also disabled CSM to be sure it’s not messing up but it doesn’t change the problem with or without CSM.
Any idea where to look at?