[vortex] Strange Link Behaviour of 3C90x Card with Fiber Converters

[Patrik Schindler]

Hello,

I want to report a long standing problem, which I now chased down a bit.

We use the following setup:

 +---------+   +--------+       +--------+   +--------+
 | 3C90x   +---+ LWL-TP +-------+ LWL-TP +---+ Switch |
 +---------+   +--------+       +--------+   +--------+

The Cards are both 3C900(B) and 3C905(B&C-TX).
The Converters are Allied Telesyn with link-thru feature and 
Auto-Negotiation support (MC-xxx).
We tested some types of switches: Allied Telesyn, 3Com 3300 Series and two
No-Name products. All show the same behaviour. The most interesting part 
is that simple (single speed) hubs just work.

After connecting the device(s) no link could be established. When I type
an "ifconfig eth0 down" and thereafter an "ifconfig eth0 up" then I can
see from the LEDs that the card establishes a link to the first converter.
This device itself switches on the link of the fiber side. The other
converter switches the link on the ethernet side on. Then the switch
itself recognizes the signal and sends it's link-signal back. When the
link arrives back at the card, the card (or the driver) has given up. The
link is gone.

The whole process takes only a few seconds, maybe 1 or 2.

The only way to get the thing running is:

Ifconfig card down
Switch link test on the converter at switch side on
ifconfig card up
Switch link test off again. Than the link doesn't vanish.

I'm sure that this problem is card/driver related, since a Intel
EtherExpress Pro doesn't show this behaviour. The card itself performs a
bit slower under linux and that's why I'd like to stay with 3Com. But to
do this procedure everytime after a reboot is a bit nasty.

Thanks for any advice.

MfG, P. Schindler
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