Tim Waugh (tim@cyberelk.demon.co.uk)
Wed, 1 Apr 1998 00:51:57 +0100 (BST)


The behaviour of the printer driver has changed between 2.0 and 2.1 in
that it now defaults to being interrupt-driven if parport can find out the
IRQ to use. It's been suggested that this is a bad thing, since it can
cause clashes that previously would have caused no harm.

So, my plan is to utilise tunelp. lp defaults to polling until given a
non-zero IRQ by tunelp -i. Then it uses whatever IRQ parport found, or
returns -EINVAL if there was none. (Currently, tunelp -i will always
get -EINVAL.)

This has the obvious nasty of completely ignoring the number specified to
tunelp. The correct thing to do to specify the IRQ, of course, is to tell
parport all about it.

That way, tunelp provides a means of enabling/disabling interrupt-driven
operation, but cannot specify which IRQ to actually use.

It would also be good to have a module parameter to enable
interrupt-driven operation from the outset. A kernel parameter would be
good too, but I can't think of a good syntax for it (anyone?).

What do people think?


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This archive was generated by hypermail 2.0b3 on Wed 30 Dec 1998 - 10:17:34 EST