Re: Backoff algorithm

[Andrey Lukyanenko <laser.ru@gmail.com>]

Thanks a lot for your help.

I have found OpenFWWF project, which has open source firmware for Broadcom
chipsets. Unfortunately it does not support CTS/RTS, AP.
What do you mean by " influencing the value you give the hw"?
Are you talking about direct access to registers? How can I influence.
I have heard about tos-mac (TinyOS) which uses directly registers but it
is for sensors. Do you mean something similar?

In our group we have five ar5213 chips, I hope I can try to use it.

On Thu, Dec 17, 2009 at 4:54 PM, Johannes Berg
<johannes@sipsolutions.net> wrote:
> On Thu, 2009-12-17 at 16:10 +0200, Andrey Lukyanenko wrote:
>> Hello Everyone,
>>
>> I wanted to find implementation of backoff protocols for different platforms.
>> I tried to find it in various open-source drivers in linux-sources, madwifi and
>> stlc45xx. Everywhere I could only find some initialization of CWmax, CWmin, ...
>> but not the actual algorithm (something like, cw = min(cw<<1 + 1, cwmax) ),
>> except ath_rate sample/mistrel where the operation is used for "best
>> rate measurement"
>> as I understood.
>> Am I correct to assume that the protocol is implemented in firmwhere and there
>> is no open source driver which I could use to "play" directly with it?
>
> Yes, basically. It's not something you can really implement in any
> driver anyway as it's very timing sensitive.
>
> ar9170 even has this in hardware, afaik, although you can of course play
> with it in b43 firmware and/or ar9170 by influencing the value you give
> the hw.
>
> johannes
>



-- 
Best regards,
Andrey Lukyanenko.