re* in an hvm environment

[iMil <imil%home.imil.net@localhost>]

Hi NetBSD-users,

I've setup some NetBSD-virtualized platforms, and ran across some hint you 
may be aware of, but this can save you time.

This hint works for both Linux/Xen 3.1 hvm and Linux/kvm hosts, with 
NetBSD 3.1 or 4.0 guests.

As you may know, the default NIC emulated by QEMU backends is a RTL8139 
model. This card is supported by two drivers in the NetBSD kernel, re(4) 
and rtk(4). By default, it's re(4) that takes the lead, but shortly after 
booting your NetBSD guest, every time you'll try a network transfer you 
see the one and famous :

re0: watchdog timeout

Which of course will lead to horrible timeouts during transfers. I tried 
many many combinations, including different media options, sync'ing 
to current and so on.

The solution was given by Manuel Bouyer 2 years ago in the port-xen list :

http://mail-index4.netbsd.org/port-xen/2006/10/25/0001.html

And indeed, when commenting out re(4) support, rtk(4) will take the lead, 
allowing a rtk0 interface running at 100BaseTX/FDX to work perfecly, 
without any timeout.

I'm running many guests configured this way, 2 on Xen 3.1 hvm, and 3 on 
Linux/kvm, they're all serving perfectly for 3 month now.

FYI, the exact same problem exists on OpenBSD, but I didn't try an 
alternative driver yet.

Hope it helps,

regards

----------------------------------------
Emile "iMil" Heitor <imil%home.imil.net@localhost>                              
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