> > Zero is "no IRQ", please use that for polling not "< 0" > > > However, platform_get_irq() will happily return IRQ#0, and it's a valid > vector on plenty of machines. NO_IRQ is also < 0 on at least FR-V, ARM, > blackin, PA-RISC, some PowerPC, and even IDE. No it is not. The platform IRQ code is responsible for ensuring that 0 is not a real IRQ and doing any neccessary remapping. Large parts of the kernel assume that - IRQ 0 is "no IRQ assigned" (serial, pci, ide etc ) - IRQ is *unsigned* > We do have some devices that are physically on IRQ#0 that otherwise work > fine, they aren't ATA devices mind you, but to claim that IRQ#0 isn't a > valid vector is not in line with what hardware actually does, whether > it's a good idea or not. In our case the IRQ vector maps to an exception > offset, which we bump down to zero. We could force an off-by-1 there so > that the math that indexes IRQ#0 is bumped up one, but that entails > fixing up every one of our IRQ numbers for no obvious gain. > > I don't really see any value in purposely crippling the range of > allowable vectors for these machines. Though I don't mind switching to a > NO_IRQ comparison instead of the < 0 case, so both can be handled. NO_IRQ is an obsolete old-IDE hack. http://www.uwsg.indiana.edu/hypermail/linux/kernel/0511.2/2197.html http://www.uwsg.indiana.edu/hypermail/linux/kernel/0511.2/1789.html Alan - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
