Card stops transmitting and Linux crashes with 1.03

James Stevens
Tue Sep 1 04:48:48 1998

Hi All,

We have just received a B-Com WinNet II box which is a super-cute PC
about the size of 500 sheets of paper. It is a P200 based on the MediaGX
chipset (PC on a chip). It has an 82558 chip on the main board. I have
compiled the driver as a module and loaded it in. It detects the chip
fine and basic networking is OK.

I have a simple unix program we use to stress ethernet called
"open_socket". It connects to port 19 ("chargen") and get as much data
as it can, giving a bytes per second stats every second, I can give you
source, but it's not difficult to guess what it looks like - "open tcp
socket, do lots of reads". It is useful for getting a idea as to how
much bandwidth is available between two points and stresses the tramsmit
and receive of the ethernet driver in a quick and easy way. It is also
esp. useful for seeing CPU utilisation under heavy TCP load.

With an NE2000 (for $10) we can get 1,200,000 bytes per second on 10Mhz
ethernet. Running with the Intel chip and V1.03 of the driver on a 10Mhz
ethernet it locks Linux. Total lock-up, reset button to re-boot, but no
register dump etc. just a total lock-up.

It starts by going really slowly, the data rate falls like a stone. If I
interupt the test at that point the system will recover. If I leave it
until the data rate stops then I get the total lock-up.

We do business with Doug Karl (you may know him for the free-ware
firewall called the KarlBridge), a collegue of mine spoke to him about
his driver for this chip and he says that Intel admitted that there was
an issue (undocumented feature), somthing to do with there being a flag
missing to tell you the transmit buffer was full, but he could not
clearly remember the exact details, just that they had had to implment a
really dirty work-around for this chip, meantime we'd love to be able to
use this mini-PC, but the Linux driver is (curently) no good... any
thoughs ?

   | James Stevens | |
   |           Tel | 01494 464264             |
   |           Fax | 01494 445374             |
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