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From: EL-HOIYDI Amre (amre.el-hoiydi_at_csem.ch)
Date: Fri Jul 26 2002 - 09:47:40 CDT

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    > > I have already tried the command "iwconfig wlan0 txpower off":
    > > Using the hostap_cs driver in managed mode (or ad-hoc), I have measured
    > > that the consumed current drops from 147 mA (txpower auto) to 125 mA
    > > (txpower off). I hopped to have a current of 17 mA with (txpower off) as
    > > indicated in the datasheet for the idle mode. It seems that there are
    > > more things that could be shut down.
    >
    > I would go through BBP data sheet and possibly test setting the
    > registers with 'iwpriv wlan0 writemif'. I don't think there is much new
    > informantion regarding power saving in newer versions of the manual.
    >

    I had a look at the HFA3861B datasheet. I did not find anything more
    than putting 255 in register 13, as you did. I have seen there that the
    normal operation is when the MAC controller puts the rest in sleep mode
    using the TX_PE and RX_PE signals. This is probably what happen when the
    MAC port is disabled.

    > It would also be interesting to test what kind of effect on power
    > consumption is on disabling the MAC port. Host AP driver does not have a
    > specific command for this yet, but it could be added if it is useful.
    > Anyway, you can test it by loading the module with 'modprobe hostap_cs
    > delayed_enable=1 disable_on_close=1'. Then the MAC port0 will be
    > disabled when the netdev is down.
    I have tried what you proposed and it works !

    rmmod hostap_cs
    insmod hostap_cs delayed_enable=1 disable_on_close=1
    ifconfig wlan0 10.11.1.1 up
    -->147 mA current consumption
    ifconfig wlan0 10.11.1.1 down
    -->18 mA current consumption !

    I think that an iwpriv command to directly disable the MAC port would be
    very usefull. I would like to keep the wlan0 port up and configured and
    put the radio to sleep periodically. The duration of the state change
    phases (sleep->ready and ready->sleep) should be as short as possible to
    reduce the power consumption overhead.

    Thanks a lot for you advice.

    Best regards,

    Amre El-Hoiydi
    (I have to go now, I will be back in three weeks).