Re: PCMCIA Power management

--
On Thu, Jul 19, 2001 at 04:26:49PM +0100, Will Stephenson wrote:
> On Thursday 19 July 2001 2:48 pm, James ''Wez'' Weatherall wrote:
> > Does anyone know how difficult it is to put a WaveLAN card into sleep
mode
> > from user space?
> >
> > Obviously, I could just use "cardctl eject" to do it, but that's rather
> > heavyweight when all I really want to do is switch the card off for a
short
> > period to save power, without tearing down DHCP and so on.
>
> I'm experimenting myself, but do you think the various 'iwconfig eth0
> power....' options might be useful here?
Hmm, interesting. It seems the version of iwconfig on my ipaq is different
than on my laptop, since the manpage on my laptop gives a power option that
is not recognized (timeout) or, perhaps, not supported by the card.
However, using:
iwconfig eth0 power on
Has some affect. On a relatively busy wireless network (university
office/clasroom building) I get a barely visible, flickering power led,
but the network stays up, and functional. When I browse slashdot.org
with dillo, for example, the light comes on solid while loading.
I'll try it in the other building, where there's a lot less wireless
traffic. I'm guessing it'll go to sleep, and stay that way.
Sounds like what James is looking for, perhaps?
--
Looking at this, it works rather well.  Much better than under CE at any
rate.  The LED will never go completely off - if it did that then no-one
would ever be able to transmit to it! :)
I was really looking for some sort of low-latency on/off API, so that I can
run my own low power protocol stack, but the in-built stuff looks very
promising.
Cheers!
---
James "Wez" Weatherall
          "The path to enlightenment is /usr/bin/enlightenment"
Laboratory for Communications Engineering, Cambridge - Tel : 766513
AT&T Labs Cambridge, UK                              - Tel : 343000