Re: debugging lack of link events

[Dan Williams <dcbw redhat com>]

On Wed, 2005-08-10 at 11:19 -0400, Derek Atkins wrote:
> Dan,
> 
> Any suggestions for how to debug the fact that NM isn't receiving
> link-up/link-down events from my e1000 after suspend/resume?  I really don't
> know enough of the udev/hal/dbus interaction to know where to start looking,
> nor do I understand the underlying protocols well enough to know how to insert
> myself and watch all the traffic...
> 
> Any (1st grade, even) suggestions would be greatly appreciated.  I find it quite
> hard to live with losing network after a suspend/resume.

Ok, my debugging with e1000 (2.6.12-1.1448_FC5) indicates that it only
notices carrier ON events after 25 - 30s, and carrier OFF events after
50s.  This is, frankly, suboptimal.

If you want a really, really quick and dirty way to figure this out:

watch -n 1 "cat /sys/class/net/eth0/carrier"

And time it with a wall clock from when you plug the cable in to when
the output changes to a '1'.  Same for unplug, look for '0'.  I found
there isn't a difference between my netlink socket testcase and
monitoring the drivers's carrier file in sysfs (they both actually come
from the same place in the driver anyway).

Dan