Stan, FYI, There are nine powerpc-specific changes in 5.13. It may make sense to start rolling back those commits first: https://kernelnewbies.org/Linux_5.13#POWERPC
On 10/6/2021 10:00:16 AM, Stan Johnson <[email protected]> wrote: On 10/6/21 4:25 AM, John Paul Adrian Glaubitz wrote: > On 10/6/21 01:40, Riccardo Mottola wrote: >> Again, booting an old kernel leads to working X. > Very much sounds like a kernel regression that you should bisect. > > That isn't too difficult when cross-building with a fast x86_64 machine. > > Adrian > I can confirm that X is not working on a PowerPC G4 Cube with the stock Debian kernel "vmlinux-5.14.0-2-powerpc". X does work with the stock Debian kernel "vmlinux-5.10.0-8-powerpc". In both cases, I'm using the latest Debian SID with Xfce. In 5.14.0-2, wdm runs but the system console screen remains blank (the LCD backlight is on). (BTW, I have a PowerBook G4 12" 1.5GHz, but I didn't test the 5.14 kernel there. The PB G4 overheats and shuts off whenever it runs anything CPU-intensive, such as a Gentoo upgrade or even compressing a file. I think Apple had a way of throttling the CPU speed to prevent overheating -- it doesn't have any problems with Mac OS X Tiger or Leopard -- but they probably didn't share the details.) I'll attempt a bisect, starting with mainline v5.14 and going backwards if necessary (it looks like 5.12.9 worked; I'm not sure about v5.13). If there's a kernel regression, I'll confirm the regression exists on both the G4 Cube and the PB G4. I don't have an iBook to test. -Stan
