orinoco_cs - sleep in ad-hoc demo mode ?

[Jouni Malinen]

On Fri, Jul 26, 2002 at 12:35:26PM +0200, EL-HOIYDI Amre wrote:

> 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.

Intresting.. I have never measured how much power the card consumes, but
I though I disabled everything that could be disabled in the BBP with
'txpower off'. Although, MAC side is probably using all power still. It
might be useful to go through all BBP configuration registers and check
if there are something else that could be disabled.

> I have also tried to use the hostap_cs driver in managed mode with power
> save on (iwconfig wlan0 power 100ms). The power consumption stays at 144
> mA, and the ping delay is below 4 ms. Hence, power save for clients
> doesn't seem to work on my system (with a Lucent access point). Is this
> implemented in hostap_cs ? And is the IBSS low power mode implemented ?

I noticed this some days ago.. It is supposed to be implemented and it
seems to configure the card as I would hope it would. However, it
certainly did not work (i.e., the station card did not use power saving
with the AP). I will need to debug this a bit more.

> I would be very happy to contribute in implementing a very low power
> sleep mode in hostap_cs. I would just appreciate some pointers to start
> understanding your code. I have the HFA3841 Driver Programmer's Manual
> version 1.61. It is probably outdated. Is it useless ? If yes, I can try
> to get a new one from Intersil.

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.

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.

> If you want to try things yourself, I could also just do the current
> measurements for you, if you do not have the hardware available.

I don't have PCMCIA extender at home so it would require a bit work to
perform the measurements.. Should I find something that could reduce the
power cosumption, I can send you some test code for measurements.

> Do you think that the sleep mode will work better with Prism 2.5 cards ?
> I am using a D-Link DWL650 (STA 0.8.3, PRI 0.3.0, NIC 1.0.1).

I don't know. I haven't tested it, but combined MAC+BBP might have some
advantages also on this.

-- 
Jouni Malinen                                            PGP id EFC895FA