Messages in this thread Patch in this message | | | Date | Fri, 26 Jan 2007 11:50:50 +0100 | Subject | Bugfixes: PCI devices get assigned redundant IRQs | From | "Andreas Block" <> |
| |
Hi,
I'm currently working on a port to a CPCI board with a MPC5200. When testing the PCI interrupt routing, I discovered the following: Even devices which don't use interrupts (-> PCI Spec.: Interrupt Pin Register is zero), get an interrupt assigned (this is at least true for most of the PPC-targets I looked at). The cause is pretty obvious in drivers/pci/setup-irq.c. I guess at least in an ideal world with correctly designed hardware, the code should rather look as in the patch below. Of course it doesn't hurt anybody to have an unuseable IRQ assigned to a PCI-to-PCI-bridge (or something alike), but to me it seems a bit strange. Please correct me, if I'm mislead.
The patch below is tested on the above mentioned CPCI-MPC5200 board and is compiler tested with the latest git-repository kernel on x86.
Best regards, Andreas
---
Don't assign IRQs to devices, which don't need any
--- commit 2133d61f0bc119d4a06d453b8e79980912a151f0 tree 59ff1b5f7c1ec41780907edd90a35c10a64e3996 parent 99abfeafb5f2eea1bb481330ff37343e1133c924 author Andreas Block <andreas.block@esd-electronics.com> Thu, 25 Jan 2007 17:12:48 +0100 committer Andreas Block <andreas.block@esd-electronics.com> Thu, 25 Jan 2007 17:12:48 +0100
drivers/pci/setup-irq.c | 18 ++++++++++-------- 1 files changed, 10 insertions(+), 8 deletions(-)
diff --git a/drivers/pci/setup-irq.c b/drivers/pci/setup-irq.c index a251289..568f187 100644 --- a/drivers/pci/setup-irq.c +++ b/drivers/pci/setup-irq.c @@ -24,7 +24,7 @@ pdev_fixup_irq(struct pci_dev *dev, int (*map_irq)(struct pci_dev *, u8, u8)) { u8 pin, slot; - int irq; + int irq = 0;
/* If this device is not on the primary bus, we need to figure out which interrupt pin it will come in on. We know which slot it @@ -33,16 +33,18 @@ pdev_fixup_irq(struct pci_dev *dev, apply the swizzle function. */
pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin); - /* Cope with 0 and illegal. */ - if (pin == 0 || pin > 4) + /* Cope with illegal. */ + if (pin > 4) pin = 1;
- /* Follow the chain of bridges, swizzling as we go. */ - slot = (*swizzle)(dev, &pin); + if (pin != 0) { + /* Follow the chain of bridges, swizzling as we go. */ + slot = (*swizzle)(dev, &pin);
- irq = (*map_irq)(dev, slot, pin); - if (irq == -1) - irq = 0; + irq = (*map_irq)(dev, slot, pin); + if (irq == -1) + irq = 0; + } dev->irq = irq;
pr_debug("PCI: fixup irq: (%s) got %d\n", - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |