I have Ubuntu 18.04.1 installed on my Raspberry Pi and two USB devices attached: One small bluetooth adapter and one small Wifi adapter. I am connecting to the wifi network with wpa_supplicant like that:
sudo wpa_supplicant -B -D wext -i wlan0 -c /etc/wpa_supplicant.conf
and then requesting an IP address from the router with dhclient:
sudo dhclient wlan0
However, now syslog and kern.log are growing and being polluted with CPU frequency errors:
Oct 12 21:52:45 ubuntu kernel: [83711.483509] cpufreq: __target_index: Failed to change cpu frequency: -22
Oct 12 21:52:46 ubuntu kernel: [83711.554489] bcm2835-cpufreq:bcm2835_cpufreq_set_clock:76: Failed to set clock: 600000 (-12)
Oct 12 21:52:46 ubuntu kernel: [83711.626640] bcm2835-cpufreq:bcm2835_cpufreq_driver_target_index:175: Error occurred setting a new frequency (600000)
To "solve" the problem I just set the max frequency in the kernel:
echo 60000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq
Pro: The pollution in the logs stop. Con: The Rpi gets unusable. Number of Zombie processes grows, starting new processes takes way longer, ...
Can anybody help? Preferably with an explanatory answer :)
Had the same problem on raspi 3B, Debian buster, after plugging in an AX88179 ethernet adapter.
echo "performance" > /sys/devices/system/cpu/cpufreq/policy0/scaling_governordid the trick for me. Raspi works fine.