patch: i8259.c & PCI int ack

hollis at hollis at
Wed Dec 5 02:46:00 EST 2001

On Mon, Dec 03, 2001 at 04:09:23PM -0600, hollis at wrote:
> - i8259_irq has been renamed to i8259_poll
> - a new i8259_irq has been added, which uses the PCI int ack address
> - both i8259_irq and i8259_poll are no longer passed the unused 'int cpu'
> - i8259_init now takes a 'long intack_addr', which on PReP is 0xbffffff0.
>   For platforms that only poll, this argument is irrelevant and can be 0x0
> - IO resources 0x20-0x21, 0xA0-0xA1, and 0x4D0-0x4D1 are now reserved
> - ISR selection is done once at initialization rather than on every irq
> This patch works on my (PReP) PowerSeries 830 and fixes the interrupt death
> problems I and others have seen.
> If this is the right idea, I intend to change all 8259 users:
> - ppc_md.get_irq = i8259_irq       ->   ppc_md.get_irq = i8259_poll
> - i8259_init()                     ->   i8259_init(0x0)
> - i8259_irq(smp_processor_id())    ->   i8259_poll()

Here is the complete patch. I have not compile-tested all N embedded targets.
The only arch actually using i8259_irq (rather than i8259_poll) right now is
PReP. From the last 8259 thread, I think all current boards *could* use it if
they wanted to.

I noticed that quite a few boards have code like this:
	/* Resolves the open_pic.c build without including i8259.c */
	int i8259_irq(int cpu)
		return 0;
That and the #ifndef CONFIG_GEMINI (maybe Gemini should have a dummy function
too to remove #ifdefs) suggests there's something wrong with open_pic.c, but I
guess everyone already knows that.


** Sent via the linuxppc-dev mail list. See

More information about the Linuxppc-dev mailing list