On Sun, Jul 28, 2013 at 6:45 PM, Alexander Holler <hol...@ahsoftware.de> wrote: > Am 28.07.2013 18:25, schrieb Linus Walleij: >> On Sun, Jul 28, 2013 at 4:25 PM, Alexander Holler <hol...@ahsoftware.de> >> wrote: >> >>> By the way, if someone decides to touch omap_hsmmc, the driver wrongly >>> assumes that 0 is not a valid IRQ number and it doesn't check if >>> gpio_to_irq() returns a negative value. ;) >> >> Zero *is* *not* a valid IRQ number. > > Where is that mentioned?
This has been a major debate in the kernel in recent months, and we are agreed to remove 0 as a valid Linux IRQ number. The fact that up until two years ago the ARM kernel allowed it is a historical artifact. Please see this article for background: http://lwn.net/Articles/470820/ Which falls back to this posting from Torvalds: http://linux.derkeiler.com/Mailing-Lists/Kernel/2005-11/7628.html > gpio.txt states: > > ---- > Non-error values returned from gpio_to_irq() can be passed to request_irq() > or free_irq(). They will often be stored into IRQ resources for platform While IRQ 0 is not an error, it means that this particular GPIO line does not have an IRQ, or cannot be translated into an IRQ, and should not be passed to request_irq(). Patches to the documentation is welcome. > With the new patches gpio_to_irq() returns 0. This is not good. Under which circumstances does that happen? > Documentation/IRQ-domain.txt: > ---- > The legacy map should only be used if fixed IRQ mappings must be > supported. For example, ISA controllers would use the legacy map for > mapping Linux IRQs 0-15 so that existing ISA drivers get the correct IRQ > numbers. > ---- > > You see the 0 too? Is OMAP still using the legacy map? I don't think that works on any system utilizing the GIC driver. It is called legacy because it is not supposed to be used :-/ > Of ourse, I might be wrong, but you just stated that 0 isn't valid, and > I would be happy to find a source for your statement. See above. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
