Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> writes:
> So looking at this, I wonder...
>
> Why is that FLAG_LINK_INTR thing not just always used?
>
> The _only_ thing that FLAG_LINK_INTR does is to cause
>
> usbnet_link_change(dev, 0, 0);
>
> to be called after network device attach. That doesn't seem to be controversial.
Not all usbnet drivers support carrier detection, which is required to
ever bring the link up again.
> Looking at some examples, we have ax88179_178a.c that doesn't set the
> flag, but instead does that usbnet_link_change() call at the end of
> ax88179_bind().
>
> There are a few drivers that seem to never call that
> usbnet_link_change() at all, and don't have that FLAG_LINK_INTR flag.
> Would they break?
Yes. Drivers without carrier detection will be "down" forever.
> Why is it called "FLAG_LINK_INTR" anyway? There doesn't seem to be
> anything "INTR" about it.
Beats me. I can only say that I always find naming difficult...
We could ask Ben, who introduced it in:
commit 37e8273cd30592d3a82bcb70cbb1bdc4eaeb6b71
Author: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Date: Wed Nov 4 15:29:52 2009 +0000
usbnet: Set link down initially for drivers that update link state
Some usbnet drivers update link state while others do not due to
hardware limitations. Add a flag to distinguish those that do, and
set the link down initially for their devices.
This is intended to fix this bug: http://bugs.debian.org/444043
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
But I guess it doesn't really matter.
Bjørn
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