On 1/5/19 3:09 PM, Major Hayden wrote: > I recently got an Orange Pi PC 2 and Fedora 29 is working quite well on it. The only issue I'm having is occasional RCU stalls and I've read some reports that reducing the maximum CPU frequency can improve this a bit on these boards. > > However, I can't find any cpufreq-related tunables for any of the CPUs: > > # ls -al /sys/devices/system/cpu/cpufreq/ > total 0 > drwxr-xr-x. 2 root root 0 Jan 5 15:42 . > drwxr-xr-x. 10 root root 0 Jun 22 2018 .. > > It looks like everything related to SUNXI or CPUFREQ in the kernel config is either a module or built into the kernel. I've found some other threads talking about ensuring the right CONFIG_REGULATOR_* options are enabled, but I'm not sure what the correct one might be for this board. > > Am I missing something important here to regulate the CPU frequency? Thanks! After more digging, I found that the device tree has no 'operating-points' for the CPU: https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/allwinner/sun50i-h5.dtsi#L50-L76 It appears that cpufreq_dt has no idea how to handle CPU frequencies without knowing the voltage/frequency relationship. Is this something that the vendor must provide? -- Major Hayden _______________________________________________ arm mailing list -- arm@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to arm-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/arm@xxxxxxxxxxxxxxxxxxxxxxx
