On Oct 23, 2006, at 11:35 AM, Scott Wood wrote:
> This patch causes ipic_set_irq_type to set the handler directly rather
> than call set_irq_handler, which causes spinlock recursion because
> the lock is already held when ipic_set_irq_type is called.
>
> I'm also not convinced that ipic_set_irq_type should be changing the
> handler at all. There seem to be several controllers that don't and
> several that do. Those that do would break what appears to be a
> common
> usage of calling set_irq_chip_and_handler followed by set_irq_type,
> if a
> non-standard handler were to be used. OTOH, irq_create_of_mapping()
> doesn't set the handler, but only calls set_irq_type().
>
> This patch gets things working in the spinlock-debugging-enabled case,
> but I'm curious as to where the handler setting is ideally supposed
> to be
> done. I don't see any documentation on set_irq_type() that clarifies
> what the semantics are supposed to be.
Guys, Scott pointed this problem out on a PPC interrupt controller,
and wanted to raise it in a larger forum since it appears to exist on
at least one ARM interrupt controller I looked at (ixp4xx). What is
the proper solution to handle this.
The callers of set_type() I found all grab desc->lock.
- kumar
>
> Signed-off-by: Scott Wood <[email protected]>
> ---
> arch/powerpc/sysdev/ipic.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/sysdev/ipic.c b/arch/powerpc/sysdev/ipic.c
> index bc4d4a7..746f78c 100644
> --- a/arch/powerpc/sysdev/ipic.c
> +++ b/arch/powerpc/sysdev/ipic.c
> @@ -473,9 +473,9 @@ static int ipic_set_irq_type(unsigned in
> desc->status |= flow_type & IRQ_TYPE_SENSE_MASK;
> if (flow_type & IRQ_TYPE_LEVEL_LOW) {
> desc->status |= IRQ_LEVEL;
> - set_irq_handler(virq, handle_level_irq);
> + desc->handle_irq = handle_level_irq;
> } else {
> - set_irq_handler(virq, handle_edge_irq);
> + desc->handle_irq = handle_edge_irq;
> }
>
> /* only EXT IRQ senses are programmable on ipic
> --
> 1.4.2.3
>
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