[patches 6/8] pcmcia: remove racy try_irq()

David Hinds dhinds at sonic.net
Tue Jan 11 19:15:40 EST 2005

On Tue, Jan 11, 2005 at 11:20:16PM +0100, Dominik Brodowski wrote:
> It depends on whether the first card is activated before the second one is
> set up, whether the respective sockets have the same lowest bit in their
> irq_mask and whether the user blocked ceratin IRQs on certain sockets (my
> patch 7/8 allows the user to do this on a per-socket basis).

By default irq_mask will generally be the same for all sockets so I
think this collision is likely to happen often; it will happen
whenever anyone boots with two cards inserted, where a serial card is
in the first-probed socket.

> Also, what's the problem of sharing IRQs in general? On my notebook, at
> least 6 devices share IRQ 10 without a problem.

That's a PCI interrupt, level triggered.  Drivers expect these to be
sharable.  Interrupt sharing --generally-- does not work with edge
triggered (ISA style) interrupts.

-- Dave

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