`6.8.0-40-generic` GPU issue on MBP (not resolved)

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1

I’ve been booting without graphics issues into linux 6.5.0-45 and 5.15.0-58, while booting into 6.8.0-40 causes issues.

Booting into 6.8.0, with large contiguous patches displaying grey instead of background image or other rendered content:

6.8.0 boot, sddm login with patchy pre-composite rendering
6.8.0 boot, sddm login with patchy pre-composite rendering4032×3024 2 MB

This same effect appeared in the terminal, Yakuake: 1) in a new terminal, 2) when more than 5 or so lines were output at once, most of the time, but each line would render when typed into or updated incrementally, and would appear when the text content was selected.

Hardware in question is:

Host: MacBookPro11,5 1.0
CPU: Intel i7-4870HQ (8) @ 3.700GHz
GPU: AMD ATI Radeon HD 8870M / R9 M270X/M370X

Secondary question: What graphics issues have people reported on 6.5.0 with KDE Neon libraries & applications? Re:

I should attempt to reproduce the issue on a distrobox container. It’s so cheap to check, that I should, even if I expect that differences lie in the kernel/driver-to-hardware relationship, i.e. from <application>-<kernel/driver>-<hardware>

2

Input lag and failure to render issues are generally display driver related. Are you using the open source or fglrx AMD gpu driver?

3

I’ve attempted to boot now into 6.8.0-45-generic instead of 6.8.0-40-generic. The same issues are present.

glxinfo tells me that neither the Intel integrated graphics nor amd gpu seem to be in use, or I don’t know how to interpret these results.

$ glxinfo | grep 'OpenGL renderer'
OpenGL renderer string: VERDE (radeonsi, , LLVM 17.0.6, DRM 2.50, 6.8.0-45-generic)

$ DRI_PRIME=1 glxinfo | grep 'OpenGL renderer'
OpenGL renderer string: VERDE (radeonsi, , LLVM 17.0.6, DRM 2.50, 6.8.0-45-generic)

I’m not sure which part of my report matches the descriptor of “input lag”, but spotty rendering, I agree, seems like a driver issue. It renders, but only in limited ways, dynamically, on demand.

It looks like fglrx would be installed, managed, or offered by ubuntu-drivers-common according to apt search fglrx. However [sudo] ubuntu-drivers devices does not report any devices that needs drivers, nor does [sudo] ubuntu-drivers list report any that I can install.

amdgpu-install, e.g. latest variant command

sudo amdgpu-install --opengl=mesa --vulkan=amdvlk --opencl=legacy --usecase=dkms,opencl,workstation,graphics,rocm -y --accept-eula seems to succeed, but does not