This is the patch I have against HEAD, which Works For Me (TM). If I
recall correctly the list in rtl8169_set_tso_csum() is from combing the
vendor drivers, but I'm not 100% on that. Too much time has passed.

I added the MAC version to the driver banner, which should make it
easier to figure out which MAC you have, and to change that function if
it does not work for you out of the box. It seems that some chips don't
work with this at all, based on testing by Michael Riepe (XID 3c4000c0).

As should be obvious, this isn't ready to go anywhere near upstream yet
I think.

Applied to 2.6.31.1 (i cannot run latest git, it is loaded proxy, too much 
risk) (one reject only, fixed by hand).

[    0.793643] r8169 Gigabit Ethernet driver 2.3LK-NAPI-TSO loaded
[    0.793734] r8169 0000:03:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17
[    0.793842] r8169 0000:03:00.0: setting latency timer to 64
[    0.793898] r8169 0000:03:00.0: irq 27 for MSI/MSI-X
[    0.794188] eth0: RTL8168d/8111d (25) at 0xf8420000, 00:1c:c0:c2:4d:df, XID 
281000c0 IRQ 27
[    2.110317] r8169: eth0: link down
[    2.110396] r8169: eth0: link down
[    3.872590] r8169: eth0: link up

Working fine now, now when i enable TX checksumming it doesn't fail. I will 
run for a while with tx checksumming, and then i will run the rest and will 
do some performance measurements (by perf tool) and i will try on a little 
bit other model of motherboard.
Thanks a lot for your patch!