r8169 MTU greater than 1500 causes corruption for other controllers

[Timothy J Fontaine <tjfontaine@atxconsulting.com>]

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Setting the MTU to greater than 1500 causes the host system to run out
of SW-IOMMU space for the transfer. This results in corruption for other
controllers like my AAR-2410SA or IDE controller.

Host system:
 ASUS P5M2 w/ Intel Core 2 Duo 6320
 Linux version 2.6.24-19-server (buildd@king) (gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu7)) #1 SMP Fri Jul 11 21:50:43 UTC 2008
 r8169 chipset pci card

Connected via Cross-Over cable to:
 SuperMicro 6014Hi
 Onboard Intel 82546GB e1000 chipset
 Running latest VMware ESXi or Vanilla 2.6.26

Initially I presumed the issue was with my aacraid because of the
trace[1], so I built a vanilla 2.6.26.2 and hit the same bug. I have
another system running 2.6.20 and the same card working so I tried
2.6.22 and had no problem. However, 2.6.23 failed. I sifted through the
ChangeLog for 2.6.23 and narrowed the field to some potential problem
commits regarding aacraid. I then proceeded to do a git bisect and found
commit b449655ff52ff8a29c66c5fc3fc03617e61182ee[2] which had nothing to
do with aacraid. Instead, the commit deals with large packets so I reset
the MTU to 1500 and retried on 2.6.24 and found that there was no
corruption, I then proceeded to try with various different size MTU only
to find that an MTU greater than 1500 triggers the corruption.

After initially encountering the bug with VMware ESXi I booted into a
vanilla 2.6.26 live cd and mounted an nfs share from the host with the
r8169 card and used dd_rescue to generate large files and transfers on
the host to expose the bug.

[1] http://tophat.atxconsulting.com/~tjfontaine/r8169_bug_report/oops_trace.txt
[2] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=b449655ff52ff8a29c66c5fc3fc03617e61182ee

Below you'll find a list of files referenced from REPORTING-BUGS that
are meant to be helpful, including the lspci and module information,
they can all be reached from the toplevel directory index

http://tophat.atxconsulting.com/~tjfontaine/r8169_bug_report/

http://tophat.atxconsulting.com/~tjfontaine/r8169_bug_report/cpuinfo
http://tophat.atxconsulting.com/~tjfontaine/r8169_bug_report/iomem
http://tophat.atxconsulting.com/~tjfontaine/r8169_bug_report/ioports
http://tophat.atxconsulting.com/~tjfontaine/r8169_bug_report/lspci
http://tophat.atxconsulting.com/~tjfontaine/r8169_bug_report/modules
http://tophat.atxconsulting.com/~tjfontaine/r8169_bug_report/oops_trace.txt
http://tophat.atxconsulting.com/~tjfontaine/r8169_bug_report/scsi
http://tophat.atxconsulting.com/~tjfontaine/r8169_bug_report/ver_linux

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