Cannot set cpu freq above 1200000

FesterBester38

Hello,

I'm trying to set the cpu frequencies on a stock Fireprime (linux kernel 3.10.0 #98) using the pseudo files located in /sys/devices/system/cpu/cpux/xxxx.
I selected a userspace governor with the command:
sudo echo userspace > /sys/devices/system/cpu/cpu3/scaling_governor
And then tried the following command:
sudo echo 1320000 >  /sys/devices/system/cpu/cpu3/scaling_setspeed
The available frequencies list includes the highest values 1200000, 1296000 and 1320000. But the frequency which is set is limited to 1200000 as shown by the command:
sudo cat /sys/devices/system/cpu/cpu3/scaling_cur_freq

Any idea why the max freq is limited to 1200000 instead of 1320000?

Thank you

zhansb

try to modify clk_core_dvfs_table in arch/arm/boot/dts/rk3128-fireprime.dts:
virt-temp-limit-*-cpu-busy:   add high cpu freq list
target-temp = <85>:  increase the temperate value

be careful of the cpu temperate, you should need heat radiating sheet or fan

FesterBester38

zhansb Posted at 1/13/2016 15:33
try to modify clk_core_dvfs_table in arch/arm/boot/dts/rk3128-fireprime.dts:
virt-temp-limit-*-cpu- ...

Thank you for your quick answer.

Do I need to recompile the kernel after such a modification?

Thx

zhansb

yes, just recompile the kernel, and  upgrade resource.img