However, I have suggested in the past that new platforms _should_ avoid
not just IRQ0 but IRQ0-15 (for a completely different reason to that of
'IRQ0 means no IRQ'.)  But such comments just get ignored, so I just
don't see the point in doing anything about this.  If people experience
breakage, so be it.  I too will have little sympathy but not for the same
reason.

The one I can think of that is capable of taking EISA/ISA cards but has
differently IRQ plumbing arrangements is PA-RISC, and they do exactly
this.

Beyond that it probably doesn't come up except in the weird world of PCI
legacy compatibility for legacy IDE and VGA vertical interrupt routing.
In those cases we fix up the PCI config space so the platform in turn can
do proper IRQ plumbing.

Alan