if_rum dies on transmit...
lstewart at freebsd.org
Tue Sep 29 20:08:07 UTC 2009
Poul-Henning Kamp wrote:
> Has anybody else seen if_rum die when you try to transmit a file over
> a TCP connection ?
> If I try to print across the network, upload a file with ftp or anything
> else of that general tenor, if_rum seems to hang the output queue and
> stops transmitting packets.
Yes I see the same thing with my D-LINK DWA-110 USB stick which shows up
as a rum device. According to Sam who had a quick look at the issue for
me when I first noticed it, the rum driver is in pretty bad shape and
should be expected to be flaky.
I don't think the issue is specific to TCP connections though. I think
it's related to timing of inbound/outbound packets. I would frequently
trigger it when fetch ran as part of a port update, but it happened at
other seemingly random times as well. I suspect that TCP incoming data
and the outgoing ACKs might tickle the (locking? state machine?) bug
more effectively than other traffic mixes.
> Restarting wpa_supplicant mostly resolves the issue, but it does not
> on its own discover the problem.
> According to tcpdump(8), packets are still received.
> Any ideas ?
I've never done any driver work so I have no idea how to resolve the
issue, and just live with it randomly crapping out on me. I found
restarting wpa_supplicant to be a hit and miss way to fix it. The
easiest way to avoid panics or re occurrences was to pull the dongle,
wait 5 secs, reinsert and then recreate the wlan dev and start
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