Scaling CPU frequency on my Espressobin v5 (1.0GHz) still has random, frequent reboots with Pali's Armada 37xx: cpufreq patch series (backported from kernel 5.13 to the 5.10 LTS kernel used in OpenWRT). I'm posting to:
- Hear from anyone else still seeing cpufreq instability on mvebu boards.
- Share my best workaround.
- Work towards a solution which allows scaling and get it upstreamed.
The workaround is to disable cpufreq:
echo "performance" > /sys/devices/system/cpu/cpufreq/policy0/scaling_governor
So this happens as early as possible to allow the system to boot reliably, instead of setting the governor through sysfs I added a kernel param (new in 5.9) to boot.scr
in /dev/mmcblk0p1
(the vfat boot partion). This requires writing a new CRC header to the file with mkimage
(included in uboot-utils
on Arch or u-boot-utils
on Debian).
cp boot.scr boot.txt
- Edit
boot.txt
- remove binary checksum header (everything before "#Espressobin" in the first line).
- add
cpufreq.default_governor=performance
mkimage -A arm64 -O linux -T script -C none -n "My Boot" -d boot.txt boot.scr
(is there a better way to change kernel params?)
CC: @hftsai256 @hmof @erdoukki from ESPRESSOBin V5 Non-eMMC Frozen on 21.02 Stable Release - #7 by hmof, others?