Re: nve0: device timeout (1)

On Tuesday 28 March 2006 01:39, David Greenman-Lawrence wrote:
Bachilo Dmitry wrote:
Patch, by the way, was rejected. I have edited if_nve.c by hands, just changed

Yep. It looks as a workaround, not a fix.


Right. It's a reasonable work-around, however, so people shouldn't be
afraid of using it. Here is my original message on this subject:


In reply to...

> It doesn't only run into timeouts, during some of these timeout the
> machine or at least the keyboard hangs for about a minute.
>
> Is there anything I can do to help debug this?

I ran into this problem recently as well and spent some time diagnosing
it. It's not that the cable isn't plugged in - rather it happens whenever
the traffic levels are low.
The problem is that the nvidia-supplied portion of the driver is defering
the releasing of the completed transmit buffers and this occasionally
results in if_timer expiring, causing the driver watchdog routine to be
called ("device timeout"). The watchdog routine resets the card and the
nvidia-supplied code sits in a high-priority loop waiting for the card
to reset. This can take many seconds and your system will be hung until
it completes.
I have a work-around patch for the problem that I've attached to this
email. It simply disables the watchdog. A real fix would involve accounting
for the outstanding transmit buffers differently (or perhaps not at all -
e.g. always attempt to call the nvidia-supplied code and if a queue-full
error occurs, then wait for an interrupt before trying to queue more
transmit packets).

What about the patch just posted to amd64@? It looks like a patch for
this issue. It changes the watchdog() routine to detect this condition
and if it happens exit the routine early without emitting a printf or
resetting the chip.

--
John Baldwin <jhb@xxxxxxxxxxx> <>< http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve" = http://www.FreeBSD.org
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