Orange Pi Zero CPU frequency scaling missing low frequencies

jscax · September 10, 2020

Hello,

I have OPI0 with Ubuntu 20.04.1 LTS with Linux 5.8.6-sunxi and I would like to set 240 MHz as minimum frequency.

cpufreq-info shows that available steps starts at 480 MHz but on older kernel 240 MHz and 120 MHz were available too.

I also tried to "force" 240 and 120 by editing /etc/default/cpufrequtils but no go.

Lower reachable frequency is 480 MHz and what I see are a bit CPU higher temperatures.

cpufreq-info
cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpufreq@vger.kernel.org, please.
analyzing CPU 0:
  driver: cpufreq-dt
  CPUs which run at the same hardware frequency: 0 1 2 3
  CPUs which need to have their frequency coordinated by software: 0 1 2 3
  maximum transition latency: 5.44 ms.
  hardware limits: 480 MHz - 1.01 GHz
  available frequency steps: 480 MHz, 648 MHz, 816 MHz, 960 MHz, 1.01 GHz
  available cpufreq governors: conservative, userspace, powersave, ondemand, performance, schedutil
  current policy: frequency should be within 480 MHz and 960 MHz.
                  The governor "conservative" may decide which speed to use
                  within this range.
  current CPU frequency is 480 MHz (asserted by call to hardware).
  cpufreq stats: 480 MHz:98.26%, 648 MHz:1.28%, 816 MHz:0.12%, 960 MHz:0.35%, 1.01 GHz:0.01%  (12233)
analyzing CPU 1:
  driver: cpufreq-dt
  CPUs which run at the same hardware frequency: 0 1 2 3
  CPUs which need to have their frequency coordinated by software: 0 1 2 3
  maximum transition latency: 5.44 ms.
  hardware limits: 480 MHz - 1.01 GHz
  available frequency steps: 480 MHz, 648 MHz, 816 MHz, 960 MHz, 1.01 GHz
  available cpufreq governors: conservative, userspace, powersave, ondemand, performance, schedutil
  current policy: frequency should be within 480 MHz and 960 MHz.
                  The governor "conservative" may decide which speed to use
                  within this range.
  current CPU frequency is 480 MHz (asserted by call to hardware).
  cpufreq stats: 480 MHz:98.26%, 648 MHz:1.28%, 816 MHz:0.12%, 960 MHz:0.35%, 1.01 GHz:0.01%  (12233)
analyzing CPU 2:
  driver: cpufreq-dt
  CPUs which run at the same hardware frequency: 0 1 2 3
  CPUs which need to have their frequency coordinated by software: 0 1 2 3
  maximum transition latency: 5.44 ms.
  hardware limits: 480 MHz - 1.01 GHz
  available frequency steps: 480 MHz, 648 MHz, 816 MHz, 960 MHz, 1.01 GHz
  available cpufreq governors: conservative, userspace, powersave, ondemand, performance, schedutil
  current policy: frequency should be within 480 MHz and 960 MHz.
                  The governor "conservative" may decide which speed to use
                  within this range.
  current CPU frequency is 480 MHz (asserted by call to hardware).
  cpufreq stats: 480 MHz:98.26%, 648 MHz:1.28%, 816 MHz:0.12%, 960 MHz:0.35%, 1.01 GHz:0.01%  (12233)
analyzing CPU 3:
  driver: cpufreq-dt
  CPUs which run at the same hardware frequency: 0 1 2 3
  CPUs which need to have their frequency coordinated by software: 0 1 2 3
  maximum transition latency: 5.44 ms.
  hardware limits: 480 MHz - 1.01 GHz
  available frequency steps: 480 MHz, 648 MHz, 816 MHz, 960 MHz, 1.01 GHz
  available cpufreq governors: conservative, userspace, powersave, ondemand, performance, schedutil
  current policy: frequency should be within 480 MHz and 960 MHz.
                  The governor "conservative" may decide which speed to use
                  within this range.
  current CPU frequency is 480 MHz (asserted by call to hardware).
  cpufreq stats: 480 MHz:98.26%, 648 MHz:1.28%, 816 MHz:0.12%, 960 MHz:0.35%, 1.01 GHz:0.01%  (12233)

thank you

5kft · September 10, 2020

It'd be worthwhile to search the forums regarding this subject, e.g., https://forum.armbian.com/topic/6398-orange-pi-zero-cpu-and-load-issues-with-538/?do=findComment&comment=58057. If you want to change this in the system, you'll have to update the appropriate DT and add the desired clock entries.