[lug] Looking for Linux device-driver course

[Rob Nagler]

Hi Jeff,

> No idea.  Could you recommend something that provides good information about
> user-level drivers, how to write them, and how to choose when to use them?

Tough call.  What's the problem?  I've done everything without books.
I bought the standard books (Embedded Linux, etc.), and they were
worthless for my application (freiker.org).  Art at NetEqualizer (who
is the author of the open source bandwidth arbitrator, btw) just
whacked on it until it worked.  He initially picked up the ethernet
bridge driver and inserted a user-level driver callback into that.
Once he did that, he wrote everything else in Perl.  The cool thing is
that he can shuffle and filter with Perl regexs on a 10mbps on a 1ghz
CPU without a problem.

> Can we expect a Linux device-driver course to cover this?

Not a big fan of courses.  I hadn't built a embedded device (Linux or
otherwise) before the Freikometer, and I haven't had a problem which I
couldn't solve with Google or the occassional message to this list.
It's all just a little bit of software, really.  You just gotta figure
out which bits. ;-)

What I would do if I was in your shoes is simply send a guy off to try
whatever it is you are going to try and do, and see what the problems
are.  Let him or her focus on the problem for a week.  The person has
to have lots of courage, because there will be oodles of gumption
traps.

I'm in the field right now upgrading all the Freikmeters in Boulder
County with an extra WiFi antenna and new software that doesn't rely
on port 22, which is blocked at most schools.  I've run into all kinds
of problems today from loading the incorrect configuration to talking
too much with people I meet on the street -- in the hope that they
donate to freiker.org.

After the week is up, have the guy email me with the problems he
couldn't solve.  I'll be happy to give some free advice on solving
them.  I personally don't think there will be many, and I can help you
evaluate whether it makes sense to continue on the path of hacking
away, or to switch to another path...

That's my $0.02...

Rob