21140 (100baseTx) w/ dual speed hub

Ken Lierman lierman@comm.mot.com
Thu Jul 1 11:57:36 1999

Just thought i'd post a followup to the message I posted yesterday....

1st, the linux tulip driver does have the same "problem".

After doing a bunch of research, I think I better understand what's
going on, although I'm not positive.  Here's some random info/facts:

- i'm using an older d21140 board, that does not support Nway
- the n-way auto-negiotation hub seems to only detect the speed of
non-nway devices after the link is removed.  If the other devices
changes on the fly, it never notices.

so, here's what I did.... after setting the Port Select in CSR6, you are
supposed to reset the 21140.   If you reset it for MUCH longer than the
minimum time, the hub see's the link go away.  Then, when you come out
of reset, the hub correctly detects the switch to 100Mb.

I'll try to do the same thing in the linux tulip.c... for myself if
nothing else :).  If anyone is interrested in using this, (or putting it
in the real driver), let me know.  I'm going to be gone all weekend, so
I probably won't be able to do it for a few days...


Ken Lierman wrote:
> All,
> This isn't linux related, but more a general 21140 question....
> I'm working on upgrading a 21140 driver to support 100baseTx.  I'm
> running through a dual speed hub to the rest of our ethernet.  When I
> initialize the driver in 100baseTx mode, the hub stays in 10baseT mode,
> but displays constant link activity.  If I disconnect the cable and plug
> it back in, the hub switches to 100baseTx and all is good.
> soooo.... am I doing something wrong in the driver, or is there
> something about the negiotation I don't understand, or ????
> The other interresting thing is the 21140 card that I have in my
> computer at home does the exact same thing under windows.... (I've never
> setup linux to run it in 100baseTx since I just got my dual speed hub.
> I'll try that tonight.)
> Thanks for any info/help!!!
> Ken Lierman
> kliermanm@bigfoot.com