Re: power management on embedded linux?


"Cliff Brake" <cliff.brake@xxxxxxxxx> wrote in message
news:1180634939.970440.70620@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On May 25, 6:56 am, "cpope" <cep...@xxxxxxxxx> wrote:
Does anyone have experience with power management on embedded linux
systems?
Is it mature and working? I specifically need my platform to do a
hibernate
where the system state is saved to a ram disk and then restored very
quickly
to wake up.

Depending on the processor, it works. If you are talking about ARM
processors, typically the SDRAM is put into self refresh, and the
processor is put into a low power state with the system consuming a
couple mA of current. On resume, you take the SDRAM out of self
refresh, and them jump to where you left off in the kernel. The
PXA270 has working suspend/resume support, so that may be a useful
reference. What processor are you thinking of using?

I know there are alot of issues with getting various devices to sleep
and
wake but I think we can handle that. I'm mostly interested in the
kernel
itself.

Yes, the kernel can typically handle it. But, this often a lot of
work to get the drivers to behave correctly, etc. The kernel does
have a mechanism to register power management callback functions, etc.

Good luck.
Cliff

====================
BEC Systems, LLC
http://bec-systems.com


My platform is a PPC inside a xilinx fpga so when I shut the processor down
I really shut it down. I'm expecting some trouble restoring the state of the
PPC on wake up but its good to here that it works on some platforms so I'm
not charting totally new water. -Clark


.

Relevant Pages

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