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    SubjectRe: down_interruptible and timers

    On Sat, 23 Jan 1999, Tim Waugh wrote:

    > Here's a code snippet from a module I'm compiling against the 2.2.0-pre9
    > source:

    > false_alarm:
    > timer.expires = jiffies + HZ;
    > = (unsigned long) port;
    > timer.function = (timer_fn) parport_ieee1284_wakeup;
    > add_timer (&timer);

    > printk (KERN_DEBUG "No signal pending\n");
    > if (!time_before (jiffies, expire)) {
    > /* Timed out. */
    > printk (KERN_DEBUG "Timed out\n");
    > break;
    > }
    > ecrval = inb (ecr);
    > if (!(ecrval & (1<<2)))
    > goto false_alarm;
    > continue;
    > }

    i think here is your problem. You've returned from down_interruptible
    without having a signal, this means you _got_ the semaphore. In this case
    you should not do the 'goto false_alarm' because you will down() forever.

    also, you say the timer wakes you up, but only if everything is OK. You
    should rather have a timer for the case that the hardware doesnt respond,
    this will then up() your process, and the process might retry 5 times if
    the hardware is not yet OK.

    -- mingo

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