[clue] [tech] How to get explicit notification from a network device driver?

[Michael J. Hammel]

On Mon, 2012-04-23 at 14:19 -0600, Jim Ockers wrote:
> It seems like it would be more deterministic, and less resource
> intensive, to just have the network card device driver DO something
> (or cause something to be done) when the link state changes.

I designed something like this for a driver at work but we never got
around to completing the implementation so can't say how well it works.
The driver was a PCIe driver that just needed to notify user space when
incoming data had arrived.

You can use an ioctl in the driver to have a process register its desire
to be notified an then have the driver raise a signal (in the top half
of an interrupt routine) for any process id that is registered.

I read that there are probably better ways to do this, and for a network
driver that is moving lots of data its probably not too good an idea,
but I think it can be done.
-- 
Michael J. Hammel                               
mjhammel at graphics-muse.org / http://www.graphics-muse.org
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