[linux-elitists] Simplest power management problem

Greg KH greg@kroah.com
Tue Aug 22 21:42:39 PDT 2006


On Tue, Aug 22, 2006 at 08:52:26PM -0400, Matthew Galgoci wrote:
> > You can easily turn off all of the above with `rmmod`, providing they've
> > been built as modules, and you can go farther -- CPU and memory hotplug
> > support are in newer kernels.  (If you have a dual-core machine and
> > are feeling particularly gratuitious, you can virtually unplug a CPU.)
> 
> Does removing a driver gurantee that the device will be left in a
> powered off state? I remember the stone ages when this wasn't always
> true. I've never really gone through the trouble to see if that is
> the case today.

No, it is still not true today.  Merely unloading the module almost
always does not turn the device off.  So don't expect to be saving any
power by doing this (there are a few minor exceptions, but they are the
exception, not the rule...)

thanks,

greg k-h



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