"AddScreen/ScreenInit failed for gpu driver 0 -1" with AMDGPU enabled on SI/Richmond Hybrid Graphics
On laptops with Southern Island hybrid graphics using a combination of the Trinity/Richmond graphics hardware (Terascale 3 and Radeon) and the Southern Island graphics hardware/variants (in this case, the Radeon 8670M), the Radeon driver works great. Try to enable the newer AMDGPU driver with "radeon.si_support=0 amdgpu.si_support=1" however and X11 just won't work with the error "addscreen failed for GPU driver 0". This happens even with disabling power management.
The laptop is an ASUS R510D, running Ubuntu MATE 22.04 with the latest kernel for said distro (6.5). Logfiles are attached for the laptop.
This bug has been previously reported here: xorg/driver/xf86-video-ati#181
And a possible fix was submitted but not approved: xorg/driver/xf86-video-ati!15 Xorg.0.log