Re: [PARPORT] parport irq handler test w/ 3 devices

Andrea Arcangeli (
Wed, 2 Sep 1998 19:48:41 +0200 (CEST)

On Wed, 2 Sep 1998, Philip Blundell wrote:

>> "parport0: irq7 happened with irq_func NULL with pda as cad"
>> message appeared ~10 times. While reading back the file I got the
>> same message some times and once I got the
>I imagine this happens because the devices get swapped when the printer is
>just about to generate an interrupt. It's harmless; we could avoid it by


>doing disable_irq() if the device that's about to be selected doesn't want
>interrupts. Alternatively we could just remove the message.

I had to remove the message with cad == NULL because after the disable_irq() I
need to run enable_irq() with cad == NULL to discard the eventually
pending IRQ.

Now irqs will happen only if the pardevice will use it and the eventually
generated irq will be discarded after the parport release. IRQ happening while
the cad is a polled pardevice will be reported as kernel error.

Andrea[s] Arcangeli

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This archive was generated by hypermail 2.0b3 on Wed 30 Dec 1998 - 10:18:13 EST