tree 1c7701d1d9d8ec9dd6ff0d692501e6850032abef
parent 661d04c6f08c16ae63fb3be05d59ee99c6f3de52
author Dominik Brodowski <linux@dominikbrodowski.net> 1122538047 -0700
committer Linus Torvalds <torvalds@g5.osdl.org> 1122565141 -0700

[PATCH] pcmcia: fix sharing IRQs and request_irq without IRQ_HANDLE_PRESENT

Debugging and description from: Noah Misch <noah@cs.caltech.edu>

When a driver calls pcmcia_request_irq with IRQ_HANDLE_PRESENT unset, it looks
for an open IRQ by request_irq()ing with a dummy handler and NULL dev_info.
free_irq uses dev_info as a key for identifying the handler to free among
those sharing an IRQ, so request_irq returns -EINVAL if dev_info is NULL and
the IRQ may be shared.  That unknown error code is the -EINVAL.

It looks like only pcnet_cs and axnet_cs are affected.  Most other drivers let
pcmcia_request_irq install their interrupt handlers.  sym53c500_cs requests
its IRQ manually, but it cannot share an IRQ.

The appended patch changes pcmcia_request_irq to pass an arbitrary, unique,
non-NULL dev_info with the dummy handler.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>