Commit 69dd3d8e authored by Linus Torvalds's avatar Linus Torvalds

Revert "irq: Always set IRQF_ONESHOT if no primary handler is specified"

This reverts commit f3637a5f.

It turns out that this breaks several drivers, one example being OMAP
boards which use the on-board OMAP UARTs and the omap-serial driver that
will not boot to userspace after the commit.

Paul Walmsley reports that enabling CONFIG_DEBUG_SHIRQ reveals 'IRQ
handler type mismatch' errors:

  IRQ handler type mismatch for IRQ 74
  current handler: serial idle
  ...

and the reason is that setting IRQF_ONESHOT will now result in those
interrupt handlers having different IRQF flags, and thus being
unsharable.  So the commit log in the reverted commit:

                            "Since it is required for those users and
    there is no difference for others it makes sense to add this flag
    unconditionally."

is simply not true: there may not be any difference from a "actions at
irq time", but there is a *big* difference wrt this flag testing irq
management (see __setup_irq() in kernel/irq/manage.c).

One solution may be to stop verifying IRQF_ONESHOT in __setup_irq(), but
right now the safe course of action is to revert the change.  Let's
revisit this in a later merge window.
Reported-by: default avatarPaul Walmsley <paul@pwsan.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Requested-by: default avatarAlan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent fcb8ce5c
......@@ -1331,7 +1331,6 @@ int request_threaded_irq(unsigned int irq, irq_handler_t handler,
if (!thread_fn)
return -EINVAL;
handler = irq_default_primary_handler;
irqflags |= IRQF_ONESHOT;
}
action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment