Re: pcmcia oops on 2.6.17-rc[12]

[Rogier Wolff <R.E.Wolff@BitWizard.nl>]

On Tue, May 16, 2006 at 12:00:26AM +0100, Alan Cox wrote:
> > So I would strongly argue that any driver that depends on getting an 
> > exclusive IRQ is buggy, not the PCMCIA layer itself, and that it would be 
> > a lot more productive to try to fix those drivers.
> 
> It would certainly be a lot cleaner than this sort of code in the pcmcia
> core right now. Want me to send a patch which only allows for SA_SHIRQ
> and WARN_ON()'s for any driver not asking for shared IRQ ?

The question I'm stuck with is: When is it valid to ask for a non-shared
IRQ, and get back a shared one. 

Drivers that know that they don't work well if they are called by the
"other" interrupt?

I happen to know (ISA) hardware that CANNOT share an interrupt: It
drives the IRQ line either high or low, and has a driver that will
overpower anything else on that line. This sounds like a good place to
me to have the driver request no sharing (*), and to prevent the IRQ
line drivers getting in eachothers way, it would be nice if the kernel
refused "early on" (i.e. before the stronger driver asserts: No IRQ
pending, and the weaker one keeps trying to assert: "YES, I have an
IRQ", and the weaker one slowly burning out).

Or am I talking nonsense again?

	Roger. 

(*) The driver knows to allow sharing when it's talking to the PCI
version of the card.

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