TX error due to colision or erroneous TX

[David Gibson]

On Tue, Feb 19, 2002 at 04:02:54AM -0500, Amit Jain wrote:
> Hi,
> I am using tests inolving TX on Lucent/Orinoco card.
> I am trying to log the TX errors either due to collision OR packet
> getting corrupted in TX. I need these types of error as a measure of  the
> congestion in link. But i am not able to know the plae where i shld log
> such errors.
> 
> In orinoco.c
> There are three places where TX errors are reported
> 
> 1> WHen transmit fails at the tim of using function "hermes_docmd_wait()"
>    in dldwd_xmit().
> 
> 2> In ISR when the "__dldwd_ev_txexc()" is called
> 
>         if (events & HERMES_EV_TXEXC)
> 			__dldwd_ev_txexc(priv, hw);
> 
> 3> On tx_timeout.
> 
> I need to know which of these three errors coorespond to what I am trying
> to log i.e. errors due to collision or erroneous TX.
> 
> 
> (1> is ruled out because that logs the error when transmit cannot be
> triggered, thus it is error due to some h/w problem)
> 
> (3> is ruled out because it can be due to h/w lockups or missing an
> interupt)
> 
> 2> seems to be the right choice..... is it really... ?????????

If collisions or corrupted transmissions are noted at all it will be
through a TxExc interrupt.  However there's no guarantee the card will
ever know about such errors, and spurious TxExcs are also possible.
The only reason it knows about any of them is the 802.11
acknowledgement protocol.

-- 
David Gibson			| For every complex problem there is a
david at gibson.dropbear.id.au	| solution which is simple, neat and
				| wrong.  -- H.L. Mencken
http://www.ozlabs.org/people/dgibson