Hi Linus !
Please, revert commit dc9372808412edbc653a675a526c2ee6c0c14a91
"of/irq: of_irq_find_parent: check for parent equal to child"
This breaks some powerpc platforms at least. The practice of having a
node provide an explicit "interrupt-parent" property pointing to itself
is an old trick that we've used in the past to allow a device-node to
have interrupts routed to different controllers.
In that case, the node also contains an interrupt-map, so the node is
its own parent, the interrupt resolution hits the map, which then can
route each individual interrupt to a different parent.
Cheers,
Ben.
On Tue, Nov 22, 2011 at 3:11 PM, Benjamin Herrenschmidt
[off-list ref] wrote:
Hi Linus !
Please, revert commit dc9372808412edbc653a675a526c2ee6c0c14a91
"of/irq: of_irq_find_parent: check for parent equal to child"
This breaks some powerpc platforms at least. The practice of having a
node provide an explicit "interrupt-parent" property pointing to itself
is an old trick that we've used in the past to allow a device-node to
have interrupts routed to different controllers.
In that case, the node also contains an interrupt-map, so the node is
its own parent, the interrupt resolution hits the map, which then can
route each individual interrupt to a different parent.
Ah, nuts, yes that is broken then. Yes, please revert the commit and
Rob & I will come up with a better solution.
Rob, I think it can be done by explicitly checking for np ==
desc->interrupt_parent in of_irq_init() instead of relying on
of_irq_find_parent() returning NULL.
g.