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authorJames Bottomley <James.Bottomley@HansenPartnership.com>2008-08-03 13:02:12 -0500
committerJesse Barnes <jbarnes@virtuousgeek.org>2008-10-23 14:54:18 -0700
commit388c8c16abafc2e74dff173b5de9ee519ea8d32f (patch)
treeed1197dcbff33881b7e285c066f1e4260be6c7a4
parent18b341b76cd99ce949806ccf5565900465ec2e7f (diff)
downloadlinux-linaro-388c8c16abafc2e74dff173b5de9ee519ea8d32f.tar.gz
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: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
-rw-r--r--drivers/pci/Makefile3
-rw-r--r--drivers/pci/irq.c60
-rw-r--r--include/linux/pci.h7
3 files changed, 69 insertions, 1 deletions
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 4b47f4ece5b..af3bfe22847 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -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
diff --git a/drivers/pci/irq.c b/drivers/pci/irq.c
new file mode 100644
index 00000000000..6441dfa969a
--- /dev/null
+++ b/drivers/pci/irq.c
@@ -0,0 +1,60 @@
+/*
+ * 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);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 752def8a2ef..c75b82bda32 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -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);