[realtek] Changing RX_BUF_LEN_IDX to 3 in 8139too stops driver from working...

[Donald Becker]

On Sun, 2 Sep 2001, Carlo E. Prelz wrote:

> Hello all. I already wrote to the list in the past to look for some
> help im identifying the reason why a single-board computer with a
> RTL-8139C chip had lower-than-expected performance. My conclusion has
> been that the responsible is the CPU (a 233MHz NatSemi Geode) that is
> not sufficient for the task. But today I came back to the problem, and
> I tried to increase the receive buffer to see if this changed
> something. 
> 
> Well, I changed RX_BUF_LEN_IDX from 2 to 3 (should bump the in-memory
> receive ring from 32k to 64k) and with this change the new kernel was
> not able to talk to the network anymore (could not find the
> nfs-mounted root partition). 
...
> Carlo (now running 2.4.9)

I'm guessing that you are using the "8139too" driver.  I suspect that it
does not correctly handle the changed wrap behavior of the chip with a
64KB receive buffer vs. a 8, 16 or 32KB buffer.

You should contact the last person to modify that driver to have it fixed.


Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
410 Severn Ave. Suite 210		Second Generation Beowulf Clusters
Annapolis MD 21403			410-990-9993