I am using a TWR-LS1021A-PB board with Linux QorIQ SDK v0.4.
I am trying to get the board to save as much power as possible, but seem to be failing. Preferable is almost no power usage when running idle. Something my product will do a lot of the time.
I am able to do DFS. Switching between 250, 500 and 1000MHz in userspace governor. However this does not seem to deliver any noticable power saving.
Also I don't see any CPU ilde driver.
What I would like to know is the following:
- How can I enable the CPU idle driver?
- Which settings need to be done in the kernel (using menuconfig), to enable all pwer management modes?
- How low can the frequency be set?
- What else can I do to make the board as power efficient as possible?
Hello Dennis Wokke
The CPU idle was default enabled in SDK v0.4. No kernel configuration needed. You can refer to the file arch/arm/kernel/cpuidle.c for the ARM cpu idle driver.
To see any significant power saving you will need to put the part in sleep / deep sleep mode.