Subject: Re: Problem with OF interrupt parsing code

From: Scott Wood <[email-masked]>
Date: Mon, 01 Oct 2007 16:37:56 -0500

Scott Wood wrote:
>> The problem occurs now, if there is no device node defined for another
>> PCI device. In this case, of_irq_map_pci() checks for an interrupt pin,
>> searches again for the host bridge node and calls of_irq_map_raw() with
>> the device node of the host bridge. The function finds the
>> #interrupt-cells, #address-cells, interrupt-controller properties, but
>> fails to find the interrupt-map property (because it's missing in the
>> device tree). Therefore the function then tries to find a new parent,
>> which leads to an endless loop (it always selects the PCI2ISA southbridge
>> in the device tree).
> 
> That seems likely... there should probably be some loop detection.

Actually, it doesn't -- it should stop when it sees the 
interrupt-controller property in the i8259 node, at which point it'll be 
trying to use the raw PCI IRQ pin number as an i8259 IRQ.  This is 
Unlikely To Work(tm).

-Scott