Ubuntu 22.04.3 x64 Kernel 6.5.0-14-generic Causes Missing Frequency and Turbo Options

[Munk3y]

After installing the latest updates today for Ubuntu 22.04, I was upgraded to Kernel 6.5. When booting, CPUFreq starts up and seemingly operates like normal but with missing Min/Max Frequency and Turbo options. I took a look for any errors using Gnome Looking Glass but there don't appear to be any. Unfortunately, I'm not fully familiar how to troubleshoot this issue but I'm happy to help, if someone can point me in the right direction. Any thoughts?

OS: Ubuntu 22.04.3 x64
Kernel: Linux Monkey 6.5.0-14-generic #14~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Mon Nov 20 18:15:30 UTC 2 x86_64 x86_64 x86_64 GNU/Linux

[Munk3y]

Ok, so I've done a large amount of reading and it looks like kernel 6.5 comes with the new amd-pstate-epp driver enabled by default. CPUFreq uses cpufreqctl to interface with the system, which no longer works, since the old acpi-cpufreq driver is no longer in use. I can only guess that parts of CPUFreq will need to be re-written to interface with the amd-pstate-epp driver at some point. In the meantime, you can revert to the old acpi-cpufreq driver in Ubuntu 22.04.3 by following these instructions:

$ sudo nano /etc/default/grub

• Change this line: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
• To this: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash amd_pstate=disable"
• Ctrl+O to Save, Ctrl+X to Exit

$ sudo update-grub
$ sudo reboot

NOTE: I do not know the repercussions of reverting this driver. There may be performance or power differences that I'm unaware of.

[Munk3y]

After following the instructions above, CPUFreq appears to be back to normal.

[peter-lyons-kehl]

(Please ignore any email from the comment that I've removed. It applied to cpupower-gui app, but not necessarily to cpufreq.)