[bug] e100 bug: checksum mismatch on 82551ER rev10

["Molle Bestefich" <molle.bestefich@gmail.com>]

Hello

I'm trying to get Linux running on a Nokia IP130 box.

The 3x Intel i82551ER NICs doesn't work.

This is the console messages (I've added printing of the checksum values):

===============================================================
e100: Intel(R) PRO/100 Network Driver, 3.5.10-k2-NAPI
e100: Copyright(c) 1999-2005 Intel Corporation
PCI: Found IRQ 10 for device 0000:00:0e.0
IRQ routing conflict for 0000:00:0e.0, have irq 11, want irq 10
e100: 0000:00:0e.0: e100_eeprom_load: EEPROM corrupted (stored: e6bc,
calc'ed: 54cf)
e100: eth0: e100_probe: addr 0x80100000, irq 11, MAC addr 00:A0:8E:22:58:58
PCI: Found IRQ 11 for device 0000:00:0f.0
IRQ routing conflict for 0000:00:0f.0, have irq 10, want irq 11
e100: 0000:00:0f.0: e100_eeprom_load: EEPROM corrupted (stored: d9cc,
calc'ed: 53cf)
e100: eth1: e100_probe: addr 0x80300000, irq 10, MAC addr 00:A0:8E:22:58:59
PCI: Found IRQ 10 for device 0000:00:10.0
IRQ routing conflict for 0000:00:10.0, have irq 5, want irq 10
e100: 0000:00:10.0: e100_eeprom_load: EEPROM corrupted (stored: d95a,
calc'ed: 52cf)
e100: eth2: e100_probe: addr 0x80500000, irq 5, MAC addr 00:A0:8E:22:58:5A
===============================================================

With vanilla 2.6.17, the e100 module dies with EAGAIN.

Apply this patch which just removes the error return path (and adds a
little debug info):

===============================================================
--- drivers/net/e100.c.orig     2006-07-09 12:03:14.000000000 +0200
+++ drivers/net/e100.c  2006-07-09 12:03:22.000000000 +0200
@@ -756,8 +756,7 @@
         * the sum of words should be 0xBABA */
        checksum = le16_to_cpu(0xBABA - checksum);
        if(checksum != nic->eeprom[nic->eeprom_wc - 1]) {
-               DPRINTK(PROBE, ERR, "EEPROM corrupted\n");
-               return -EAGAIN;
+               DPRINTK(PROBE, ERR, "EEPROM corrupted (stored: %4.4x, calc'ed: %
4.4x)\n", nic->eeprom[nic->eeprom_wc - 1], checksum);
        }

        return 0;
===============================================================

And everything works!

I think I've heard about this bug before, but I don't know why it occurs.
So the best I can do is the above (ignore failed EEPROM checksum test).

My hardware is:
00:0e.0 Ethernet controller: Intel Corporation 8255xER/82551IT Fast
Ethernet Controller (rev 10)
00:0f.0 Ethernet controller: Intel Corporation 8255xER/82551IT Fast
Ethernet Controller (rev 10)
00:10.0 Ethernet controller: Intel Corporation 8255xER/82551IT Fast
Ethernet Controller (rev 10)

I was wondering if we can just remove the -EAGAIN return from the
driver and in effect turn the EEPROM checksum stuff into a non-fatal
test?  Since I can't figure out the correct way to test the checksum
on this hardware, that seems like the best thing to do to me...