Since kernel 2.6.14 I'm having a problem with my Zaurus C860 and FC4: data transfers (over usbnet) above a certain size hang forever.
I've determined that any file with a size >= 1458 bytes will hang. Any file with a size smaller than this will transfer just fine.
This occurs regardless of the protocol: scp, ftp, and samba all fail. Additionally, browsing large directories with samba will fail (I assume this is related to the number of entries in the directory and, therefore, the size of the directory contents transfer).
The last kernel release that works is 2.6.13-1.1532. All subsequent ones fail (2.6.14-1.*, 2.6.15-1.1831).
I've google'ed some kernel activity and found some interesting stuff but nothing conclusive. I noticed that the kernel guys are still mucking around with usbnet: they've been engaged in a massive refactoring of that module since at least 2.6.11 (which I earlier discovered completely broke connectivity with the C860). I noticed one comment regarding the implementation of some sort of "hard mtu" feature which sounded somewhat suspicious to me, but I haven't researched it any further so it may be a red herring.
Does anyone have any idea how to fix this?