Date: Thu, 26 Sep 1996 10:06:10 +0200 (MET DST) From: Guido van Rooij <Guido.vanRooij@nl.cis.philips.com> To: nao@sbl.cl.nec.co.jp (Naoki Hamada) Cc: Guido.vanRooij@nl.cis.philips.com, freebsd-hackers@FreeBSD.org Subject: Re: new if_vx driver in incoming on freefal Message-ID: <199609260806.KAA06708@spooky.lss.cp.philips.com> In-Reply-To: <199609260205.LAA10545@sirius.sbl.cl.nec.co.jp> from Naoki Hamada at "Sep 26, 96 11:05:15 am"
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Naoki Hamada wrote:
> Hi.
>
> Guido, I cannot figure out what you intended the following change to
> do. Could your tell me what you meant?
>
> --- vx/if_vx.c Wed Sep 25 00:45:50 1996
> +++ vx.old/if_vx.c Tue Sep 17 16:19:42 1996
> - outw(BASE + VX_COMMAND, SET_TX_AVAIL_THRESH | (len + pad + 4));
> + outw(BASE + VX_COMMAND, SET_TX_AVAIL_THRESH | ((len + pad + 4) >> 2));
>
> BTW, I am now working on the new vx driver to make it select the right
> connector. My 3C590C card seems now good at it, but I cannot try the
> 3C595 adapter because I do not have one. Since the fast ethernet is
> extremely faster than the ordinary ethernet, parameters may have to be
> changed...
>
The reasonI changed it is because the value passed to it is set into bits
2 and higher of the register. This has the effect of multiplying by four.
In order to get the correct value in, you thus shoul firts devide it
by four. This is true for every threshold register (with the 3c59x cards).
Applying this change to the old driver still doesn't do the job for me.
(if you have the spec for the 3c59x, look at page 2-2, Large Packet Support,
and on page 4-12, SetTxAvilableThresh)
Can't you take my driver and extend it? Then we have a driver that looks far
more like the {Net,Open}BSD one which has some straightforward advatages.
-Guido
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