From: Jouni Malinen (jkmaline_at_cc.hut.fi)
Date: 2002-03-28 22:32:49 UTC
On Thu, Mar 28, 2002 at 09:08:05PM +0200, Jouni Malinen wrote:
> Yes, but it is not yet fully implemented in the driver. 'iwconfig
> wlan0 txpower off' (and 'on') is supposed to do exactly
> this. prism2_ioctl_siwtxpow() in prism2.c has the places and TODO
> comments for turning the radio off/on.
I did some further testing and apparently 'on' argument is not accepted. 'auto' (or fixed power level) can be used instead.
> Prism2 MAC has a test command for setting baseband processor
> parameters, including TX/RX power enable.
I rechecked HFA386x datasheet and there seems to be many methods for turning down power (TX and/or RX). I used CR13 (A/D TEST MODES 2) and all standby/sleep modes. In other words, 'iwconfig wlan0 txpower off' sets the BBP in standby mode that should use only minimal amount of power compared to normal operation mode. This disabled both TX and RX. See the attached patch file for the needed changes to the driver code.
It is probably also possible to disable just TX or RX, so I added new iwpriv command 'writemif' for further testing. Please, read HFA386x datasheet (http://www.intersil.com/data/FN/FN4/FN4856/FN4856.pdf) thoroughly before testing random numbers with writemif since there might be some settings that could cause physical damage to the card.
SleepTX described in the datasheet did not seem to stop TX completely. However, SleepIQ stopped TX, but still allowed RX. I'm not fully sure, which parts are disabled in that mode, so I'm using full standby mode with the 'txpower' command for now. You will need to manually set CR13 (or some other register) to disable just TX if that is the wanted behavior.
'writemif' can be used with following command: 'iwpriv wlan0 writemif <CR*2> <value to be written>' (e.g., 'iwpriv wlan0 writemif 26 17' sets bits 4 (SleepIQ) and 0 (Enable test mode commands) of CR13.
-- Jouni Malinen PGP id EFC895FA