On Wed, Nov 07, 2007 at 09:09:30AM -0500, Mark Lord wrote: > Paul Mundt wrote: > >On Wed, Nov 07, 2007 at 01:09:40PM +0000, Alan Cox wrote: > >>On Wed, 7 Nov 2007 17:10:52 +0900 > >>Paul Mundt <lethal@xxxxxxxxxxxx> wrote: > >>>By default ata_host_activate() expects a valid IRQ in order to > >>>successfully register the host. This patch enables a special case > >>>for registering polling-only hosts that either don't have IRQs > >>>or have buggy IRQ generation (either in terms of handling or > >>>sensing), which otherwise work fine. > >>> > >>>Hosts that want to use polling mode can simply set ATA_FLAG_PIO_POLLING > >>>and pass in a NULL IRQ handler or invalid (< 0) IRQ. > >>NAK > >> > >>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. > > Too bad. The Penultimate Penguin wants zero to continue to mean "no IRQ". > > Dig into the archives for multiple threads on this exact topic. > The end result is that "0" means "no IRQ". If your physical IRQ actually > is the number 0, then reencode it to some other value for this purpose. > I've read the threads, but this does little to do with the fact it's still a perfectly valid vector, and I'm not about to force every IRQ vector on my platform off-by-1 in order to satisfy a religious point of view with zero reflection on what the hardware actually looks like. So I'll change the check to IRQ#0 == invalid, but if that's to be enforced kernel-wide, then all of the existing NO_IRQ cases should be ripped out and set to 0. This way at least people are getting screwed consistently, rather than just in particular subsystems. > Yes, a bit of pain, but that's how many parts of the kernel expect it, Just as many parts of the kernel make no such assumption. > and in the end it's no more overall hassle than doing it differently might > have been. > Spoken like someone who doesn't have to contend with off-by-1 IRQ vectors as a result of an entirely cosmetic change. It's certainly easier to parrot a party line when you aren't being bitten by it. So again, I'll make the change, but it's utter nonsense. - 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
