Re: LinkSys LNE100TX Card and EPROM Burner

[Marty Connor <mdc@thinguin.org>]

I have ordered some more PCI 10/100 ethernet cards, which should arrive 
in the net few days.  When they arrive I will see which ones I can get to 
Etherboot, and will supply what patches I am able to.

In order to support more cards we need to know their PCI codes, which 
consist of a "Vendor ID" and a "Device ID".  Here is the URL which 
describes a Linux program which I believe (I haven't tested it yet) will 
display these codes:

   http://www.freshmeat.net/appindex/1998/04/20/893094449.html

[some BIOSes print out the codes every reboot, so you may just be able to 
read them off the screen]

It occurs to me, that I should put these codes in the thinguin.org card 
database.

Why do we need these codes?

It turns out that the ROM must contain the PCI IDs of the PCI card that 
it is on, becase some BIOSes do a check to make sure that the PCI IDs of 
the card match the PCI IDs of the [EP]ROM.  If they do not, the ROM will 
not be executed. It seems to be a sanity check, which makes sense, since 
the BIOS probably is looking at the address space, and doesn't actually 
know whether there is a ROM supplying the bits or not. Checking that the 
IDs of the memory image in that space matches the PCI IDs of the card 
would make sense. Does anyone know for sure how this works? I am 
presuming the PCI card doesn't do the checking.

This explains why sometimes a floppy image will work, but an EPROM will 
not work. The floppy image gets loaded by the BIOS no matter what, 
whereas the EPROM image only loads if its PCI codes match the cards.

This being said, once we have the IDs, two or three files will usually 
need to be edited. "Makefile" will need to be adjusted to create a .rom 
and .lzrom with the proper IDs, and the driver source (.c and/or .h) 
files may need to be edited, if this card requires special 
initialization/operational sequences to work properly. Then comes testing 
of the image.  The good news is, if it works with a floppy, it will 
usually work with an EPROM once one figures out what size and where to 
burn it.

If people interested in seeing more PCI cards supported would be so kind 
as to supply us with PCI codes (you can use the "PCI Utilities" mentioned 
above, or some BIOSes just print out the information in a list every 
reboot) and other identifying information such as Card Manufacturer, 
Model and any numbers on the main chip such as "MX98715AEC" it would be 
very helpful.

Thanks,

Marty

---
   Name: Martin D. Connor
US Mail: Entity Cyber, Inc.; P.O. Box 391827; Cambridge, MA 02139; USA
  Voice: (617) 491-6935, Fax: (617) 491-7046 
  Email: mdc@thinguin.org
    Web: http://www.thinguin.org/


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