My first real attempt at kernel hacking!
Matthew Dillon
dillon at apollo.backplane.com
Fri Mar 5 22:52:25 PST 2004
:Ever since Matt added systimers, my DragonFly console has been lacking
:something: an audible bell. I'm sure many people don't miss it, but I
:got used to it, especially as feedback when tab-completion fails. So I
:added a way to make syscons use my soundcard for ringing the bell.
:
:The theory of operation is very simple. Every time the bell rings, the
:syscons driver makes a byte available on /dev/consolectl. A userland
:daemon, belld, opens /dev/consolectl and reads from it, which blocks
:until a byte becomes available. When it does, belld spawns a
:user-specified program (in my case, "/usr/local/bin/madplay ding.mp3"),
:then waits for the next byte in an infinite loop.
:
:Dead simple, but effective, and a good starter project for cutting my
:teeth in the wild and woolly world of kernel programming.
:
:The files are available here:
:
: http://catseye.webhop.net/projects/belld/
:
:If I get some positive feedback, I'll clean it up and send it to
:submit at .
:
:Thanks to Emiel, Rob, and Samy for the help and encouragement :)
:
:-Chris
I like the idea! I'll take a look at the patch tomorrow. One thing
I might do (if the code doesn't already do it) is limit the number
of bells that can build up in the device driver to something reasonable,
like 2.
-Matt
Matthew Dillon
<dillon at xxxxxxxxxxxxx>
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