Re: [HELP] Power management for embedded system

[Russell King <rmk+lkml@arm.linux.org.uk>]

On Thu, Aug 24, 2006 at 08:44:25AM +0000, moreau francis wrote:
> Mips one seems to be a copy and paste of arm one and both of them
> have removed all APM bios stuff orginally part of i386 implementation.

The BIOS stuff makes no sense on ARM - there isn't a BIOS to do anything
with.

> It doesn't seem that APM is something really stable and finished.

It's complete.  It's purpose is to provide the interface to userland so
that programs know about suspend/resume events, and can initiate suspends.
Eg, the X server.

The power management really comes from the Linux drivers themselves,
which are written to peripherals off when they're not in use.  The other
power saving comes from things like cpufreq - again, nothing to do with
the magical "APM" or "ACPI" terms.

On embedded platforms, you shouldn't think about power management in
terms of the non-embedded PM technologies.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core