Re: [PARPORT] Help needed: Reenabling IRQ after IRQ-Handling with parport

Tim Waugh (
Thu, 28 Oct 1999 21:23:37 +0100 (BST)

On Tue, 26 Oct 1999, Levent [iso-8859-1] GŁndogdu wrote:

> After the irq handler is called by the parport implementation, I can
> read data from my device. Unfortunaly the irq handler gets called only
> once. I am able to read the rest of my data after reloading my module,
> because it is queued in the midi hardware. I think I need a way of
> reenabling irqs after irq processing. Is that right?

No, that shouldn't be the case. You can try calling
port->ops->enable_irq() to see if it makes a difference though. (I'm
assuming you're talking about the development branch.)

> At module initialization I probe for the midi interface using a
> specifed protocol. AFAIK I must not do something with the port until I
> claimed it. After I claim the device, IRQs get enabled and I receive
> the data BEFORE the probing. So I need a way to claim the device,
> probe for the midi interface and (after success) enable the IRQs. Do
> you know a way to achieve this?

You can call port->ops->disable_irq() to disable IRQs before probing, and
then enable them afterwards when you're ready. You can't rely on the
state of the port hardware before you've claimed the port though.


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This archive was generated by hypermail 2.0b3 on Thu 28 Oct 1999 - 17:00:25 EDT