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Commit 388c8c16 authored by James Bottomley's avatar James Bottomley Committed by Jesse Barnes
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PCI: add routines for debugging and handling lost interrupts 



We're getting a lot of storage drivers blamed for interrupt misrouting
issues.  This patch provides a standard way of reporting the problem
... and, if possible, correcting it.

Signed-off-by: default avatarJames Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent 18b341b7

drivers/pci/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -3,7 +3,8 @@ 
#



obj-y		+= access.o bus.o probe.o remove.o pci.o quirks.o slot.o \

			pci-driver.o search.o pci-sysfs.o rom.o setup-res.o

			pci-driver.o search.o pci-sysfs.o rom.o setup-res.o \

			irq.o

obj-$(CONFIG_PROC_FS) += proc.o



# Build PCI Express stuff if needed

drivers/pci/irq.c

0 → 100644
+60 −0
Original line number Diff line number Diff line 
/*

 * PCI IRQ failure handing code

 *

 * Copyright (c) 2008 James Bottomley <James.Bottomley@HansenPartnership.com>

 */



#include <linux/acpi.h>

#include <linux/device.h>

#include <linux/kernel.h>

#include <linux/pci.h>



static void pci_note_irq_problem(struct pci_dev *pdev, const char *reason)

{

	struct pci_dev *parent = to_pci_dev(pdev->dev.parent);



	dev_printk(KERN_ERR, &pdev->dev,

		   "Potentially misrouted IRQ (Bridge %s %04x:%04x)\n",

		   parent->dev.bus_id, parent->vendor, parent->device);

	dev_printk(KERN_ERR, &pdev->dev, "%s\n", reason);

	dev_printk(KERN_ERR, &pdev->dev, "Please report to linux-kernel@vger.kernel.org\n");

	WARN_ON(1);

}



/**

 * pci_lost_interrupt - reports a lost PCI interrupt

 * @pdev:	device whose interrupt is lost

 * 

 * The primary function of this routine is to report a lost interrupt

 * in a standard way which users can recognise (instead of blaming the

 * driver).

 *

 * Returns:

 *  a suggestion for fixing it (although the driver is not required to

 * act on this).

 */

enum pci_lost_interrupt_reason pci_lost_interrupt(struct pci_dev *pdev)

{

	if (pdev->msi_enabled || pdev->msix_enabled) {

		enum pci_lost_interrupt_reason ret;



		if (pdev->msix_enabled) {

			pci_note_irq_problem(pdev, "MSIX routing failure");

			ret = PCI_LOST_IRQ_DISABLE_MSIX;

		} else {

			pci_note_irq_problem(pdev, "MSI routing failure");

			ret = PCI_LOST_IRQ_DISABLE_MSI;

		}

		return ret;

	}

#ifdef CONFIG_ACPI

	if (!(acpi_disabled || acpi_noirq)) {

		pci_note_irq_problem(pdev, "Potential ACPI misrouting please reboot with acpi=noirq");

		/* currently no way to fix acpi on the fly */

		return PCI_LOST_IRQ_DISABLE_ACPI;

	}

#endif

	pci_note_irq_problem(pdev, "unknown cause (not MSI or ACPI)");

	return PCI_LOST_IRQ_NO_INFORMATION;

}

EXPORT_SYMBOL(pci_lost_interrupt);

include/linux/pci.h

+7 −0
Original line number Diff line number Diff line
@@ -546,6 +546,13 @@ struct pci_dev __deprecated *pci_find_slot(unsigned int bus, 
					   unsigned int devfn);

#endif /* CONFIG_PCI_LEGACY */



enum pci_lost_interrupt_reason {

	PCI_LOST_IRQ_NO_INFORMATION = 0,

	PCI_LOST_IRQ_DISABLE_MSI,

	PCI_LOST_IRQ_DISABLE_MSIX,

	PCI_LOST_IRQ_DISABLE_ACPI,

};

enum pci_lost_interrupt_reason pci_lost_interrupt(struct pci_dev *dev);

int pci_find_capability(struct pci_dev *dev, int cap);

int pci_find_next_capability(struct pci_dev *dev, u8 pos, int cap);

int pci_find_ext_capability(struct pci_dev *dev, int cap);