Re: [PARPORT] Questions with ppdev

From: Michael Reinelt (
Date: Fri Mar 16 2001 - 18:29:25 EST

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    Philip Blundell wrote:
    > In message <>, Tim Waugh writes:
    > >On Thu, Mar 15, 2001 at 08:45:35AM +0100, Michael Reinelt wrote:
    > >> Maybe ppdev should provide an interface to the kernel udelay()
    > >> function?
    > >
    > >Not sure. I'd rather not. Anyone else know the answer to the timing
    > >issue?
    > I don't remember what the original problem was, but I agree that ppdev
    > probably should not have a udelay function. Does nanosleep not do what's
    > needed?

    Yes, it does, but only if you run the process with SCHED_RR or
    SCHED_FIFO. And this is dangerous. If the process hangs (maybe because
    of a buggy endless loop), wo can't even kill it, because the process
    will use up all of your CPU, and you cannot type something (unless you
    have a shell running with SCHED_RR and a higher static priority than the
    hanging process).

    bye, Michael

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