On Thu, Oct 13, 2022, at 12:08 AM, Michael S. Tsirkin wrote:

On Wed, Oct 12, 2022 at 11:06:54PM +0200, Arnd Bergmann wrote:

quoted

On Wed, Oct 12, 2022, at 7:22 PM, Linus Torvalds wrote:

quoted

The NO_IRQ thing is mainly actually defined by a few drivers that just
never got converted to the proper world order, and even then you can
see the confusion (ie some drivers use "-1", others use "0", and yet
others use "((unsigned int)(-1)".

The last time I looked at removing it for arch/arm/, one problem was
that there were a number of platforms using IRQ 0 as a valid number.
We have converted most of them in the meantime, leaving now only
mach-rpc and mach-footbridge. For the other platforms, we just
renumbered all interrupts to add one, but footbridge apparently
relies on hardcoded ISA interrupts in device drivers. For rpc,
it looks like IRQ 0 (printer) already wouldn't work, and it
looks like there was never a driver referencing it either.

Do these two boxes even have pci?

Footbridge/netwinder has PCI and PC-style ISA on-board devices
(floppy, ps2 mouse/keyboard, parport, soundblaster, ...), RiscPC
has neither.

    Arnd