Subject: Re: ural(4) for NetBSD 3.0, now sync'ed with OpenBSD ural driver
To: None <,>
From: David Young <>
List: tech-kern
Date: 11/26/2005 16:06:04
On Sat, Nov 26, 2005 at 10:29:32PM +0100, iMil wrote:
> Hash: SHA1
> Hi,
> following Damien Bergamini's advice (the original author of the ral(4) 
> driver), i've synchronized yesterday's ural(4) backport with current 
> OpenBSD driver. Follow the same procedure i've given yesterday to compile 
> it. I kept yesterday's archive untouched, you'll find the new driver at 
> Damien's recent commits fixes some TX issues and add a rate control 
> algorithm for BSS mode (AMRR).


AMRR is already in the NetBSD tree, although it is coupled with ath(4);
see src/sys/dev/ic/athrate-amrr.[ch].  I prefer that the code isn't
duplicated in ural(4).

BTW, it would be enormously helpful to make the ath(4) bitrate-selection
algorithms in dev/ic/athrate-* generic, so that drivers such as atw,
ral, rtw can also benefit.

As far as bitrate-selection algorithms go, AMRR seems naive to me.
I made SampleRate (athrate-sample.[ch]) the default for ath(4), since it
is based on experimental results from 802.11 testbeds.  Alas, SampleRate
may be buggy.  I understand there are newer versions of SampleRate
somewhere on the Internet; they may fix the bugs.

AMRR is a perplexing choice for ural(4).  AMRR stands for "Adaptive
Multi-Rate Retry."  AFAICT, the ural(4) hardware does not even support
multi-rate retry.  Maybe I have overlooked something.


> regards
> - -------------------------
> iMil <>                                                 _
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David Young             OJC Technologies      Urbana, IL * (217) 278-3933