Intel ixgb driver bug in linux-2.6.17-rc6-mm2

[linas@austin.ibm.com (Linas Vepstas)]

Hi,

I sat down to do some testing of the ixgb driver a few days ago, and
get failures within seconds.  From what I can tell, I'm getting either a
DMA to a bad address or some other PCI bus error, not sure which. 
The problem appears to happen only for the driver that's in
2.6.17-rc6-mm2. As a sanity check, I'm testing the SuSE SLES10 beta,
which is 2.6.16 based, and it doesn't seem to have any problems.

My test is dirt-simple: telnet to the chargen port.  After an eyeblink,
I get the pci bus error, that's that. "eyeblink" is after about 300MBytes
transfered.  That was with a driver with NAPI enabled. I tried again
with NAPI disabled, and got to about 1.8 GB transfered in two eyeblinks.

To make sure that I'm not dealing with faulty hardware, I tried the same
thing w/ SLES10 2.6.16.18-1.8  and have gotten to RX bytes:20889480686
(19921.7 Mb) so far, with no problems. I don't have easy access to a PCI
bus analyzer, otherwise, I'd tell you more. Ideas? Suggestions? 

I could try taking the diff between these two driver versions, and
seeing what change caused the problem, but thought I should email first,
before doing that.

--linas