Quirky behavior of a 3c905b.

Jason Zwolak jzwolak@vt.edu
Thu Nov 25 09:30:00 1999

Get the mii-diag program from :

Then run something like:
mii-diag -F 100baseT4 eth0

There are some other modes than 100baseT4 that you can try (like
100baseTx), when you find one that works you can add the above line to
your conf.modules file like this:

post-install eth0 /usr/local/bin/mii-diag -F 100baseT4 eth0

Let me know if this helps.

Charles Wilcox wrote:
> I don't know if this is the right place to pose this question; if not
> please let me know and if possible let me know where to go for help; if
> not:
> I have been having some strange behavior and finally tracked down what is
> causing it, but I'm at a loss about how to fix it.  Several times in the
> past I have noticed that my computer was causing extreme collisions on a
> hub and would go away by unplugging and replugging the ethernet cable into
> either to the computer or the hub.  Recently I realized that something I
> was doing might be causing it...  This is what I currently see happening.
> I have been been using the DOS 3c90xcfg.exe program to alter the settings
> (10 vs. 100 Mb, half vs. full duplex, autodetect).  Whenever I set it to
> use 100Mbit (either half or full duplex) I reboot into Linux (Slackware 7,
> 2.2.13 kernel) and when rc.inet1 runs (I ran this manually from 'single'
> mode to be double sure) the card goes into 10Mbit mode.  This is
> irritating, but what is worse is when I restart the computer (any way
> except powerdown/powerup) the collisions start happening.  It seems to
> happen before the BIOS settings run or LILO runs (I can get into the BIOS
> screen to prevent it from booting further, but the collisions will already
> be happening.)
> Oh yea, Windows will not cause this problem.  i.e.  I can set the card to
> 100Mbit mode, boot into windows, do stuff and restart without causing
> collisions.  The connection does not drop down to 10 Mbit either.
> This is perplexing to me.  Besides this one thing the card seems to run
> fine.  I tried to upgrade the drivers (to 3c59x.c:v0.99L 5/28/99).  This
> didn't help.
> I guess if rc.inet1 didn't cause the card to switch from 100Mbit into
> 10Mbit I don't think the collisions would occur after the reset, but this
> is just a guess.  Is this defective hardware, a driver issue, or something
> with rc.inet1 like the ifconfig line?  Any hints, suggestions, or other
> thoughts?
>  -- Charles Wilcox

May the Source be with you,
Jason Zwolak 
homepage: http://zwolak.dhs.org (Isn't DHS awesome)