In order to have Tumbleweed GUI working on Kabini, one needs to install the kernel-firmware package.
Recently moved my Linux workstation to an old AMD APU platform with Kabini (Athlon 5350). The installation completed successfully, but the console goes blank and X cannot use the radeon driver and fallback to VESA.
After some digging, found that although the radeon and amdgpu modules are loaded, there are error messages in dmesg saying that some firmwares cant be loaded.
The problem can be easily fixed by installing the kernel firmware:
sudo zypper install kernel-firmware