Subject: Re: 802.11 Transmit power control
To: None <tech-net@NetBSD.org>
From: David Young <dyoung@pobox.com>
List: tech-net
Date: 10/31/2004 14:28:22
On Sun, Oct 31, 2004 at 08:52:27PM +0100, Pavel Cahyna wrote:
> On Sun, 31 Oct 2004 18:43:03 +0000, David Young wrote:
> 
> > Great!
> > 
> > My API put too much functionality in the kernel.  FreeBSD has a vastly
> > simpler API, IEEE80211_IOC_TXPOWER, which now I prefer, except with
> > these semantics:
> ...
> > 4 settings are *unitless*; if it matters, you may keep calibrate your
> >   card and keep the calibration values in userland; maybe ifconfig
> >   should render some assistance
> 
> I still see an issue with it: if the driver *knows* what are the correct
> units, why shouldn't it provide that information to userland, instead of
> requiring me to calibrate the card?

What with manufacturing variation, aging components, and the variety of
power amps, how does a driver know the correct units?  I feel fairly
certain that there is not a driver in NetBSD that can tell us with
what its transmit power units are with the certainty we need for, say,
complying with wireless regulations.

Dave

-- 
David Young             OJC Technologies
dyoung@ojctech.com      Urbana, IL * (217) 278-3933