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Date:      Thu, 21 Jul 2005 17:31:23 -0700
From:      Sam Leffler <sam@errno.com>
To:        David Malone <dwmalone@maths.tcd.ie>
Cc:        Sam Pierson <samuel.pierson@gmail.com>, FreeBSD Hackers <freebsd-hackers@freebsd.org>
Subject:   Re: Atheros, hardware access layer, collisions
Message-ID:  <42E03E5B.80905@errno.com>
In-Reply-To: <200507211849.aa11934@salmon.maths.tcd.ie>
References:  <200507211849.aa11934@salmon.maths.tcd.ie>

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David Malone wrote:
>>I was looking for this in the ah.h and the ah_desc.h files.  Are they
>>someplace else, or maybe this is a system call?  I can't find anything
>>about the retry limit (<-- CWmin = retry?)  Thanks,
> 
> 
> CWmin is a setting that controls the random delay before packets
> are transmitted. Search for tqi_cwmin in the driver. The retry limit
> says how many times the MAC should retry if it gets a collision
> while trying to transmit - I think it is controled by the tqi_shretry
> and tqi_lgretry values. In the driver in 6.X you can (in principle)
> set these values at the time the transmit queues are configured.

You need to set cwmin on the tx q as David describes.  Be sure to set 
the parameters you set into the hardware; check the wme update code for 
the correct logic.  For the other thing just set the tx descriptor to do 
1 try.

	Sam




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