blob: a1de501a27299bdd7856979e71baa4aa641e9a0a [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
* PCI IRQ handling code
* Copyright (c) 2008 James Bottomley <>
* Copyright (C) 2017 Christoph Hellwig.
#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/export.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);
pci_err(pdev, "Potentially misrouted IRQ (Bridge %s %04x:%04x)\n",
dev_name(&parent->dev), parent->vendor, parent->device);
pci_err(pdev, "%s\n", reason);
pci_err(pdev, "Please report to\n");
* 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");
} else {
pci_note_irq_problem(pdev, "MSI routing failure");
return ret;
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 */
pci_note_irq_problem(pdev, "unknown cause (not MSI or ACPI)");
* pci_request_irq - allocate an interrupt line for a PCI device
* @dev: PCI device to operate on
* @nr: device-relative interrupt vector index (0-based).
* @handler: Function to be called when the IRQ occurs.
* Primary handler for threaded interrupts.
* If NULL and thread_fn != NULL the default primary handler is
* installed.
* @thread_fn: Function called from the IRQ handler thread
* If NULL, no IRQ thread is created
* @dev_id: Cookie passed back to the handler function
* @fmt: Printf-like format string naming the handler
* This call allocates interrupt resources and enables the interrupt line and
* IRQ handling. From the point this call is made @handler and @thread_fn may
* be invoked. All interrupts requested using this function might be shared.
* @dev_id must not be NULL and must be globally unique.
int pci_request_irq(struct pci_dev *dev, unsigned int nr, irq_handler_t handler,
irq_handler_t thread_fn, void *dev_id, const char *fmt, ...)
va_list ap;
int ret;
char *devname;
unsigned long irqflags = IRQF_SHARED;
if (!handler)
irqflags |= IRQF_ONESHOT;
va_start(ap, fmt);
devname = kvasprintf(GFP_KERNEL, fmt, ap);
ret = request_threaded_irq(pci_irq_vector(dev, nr), handler, thread_fn,
irqflags, devname, dev_id);
if (ret)
return ret;
* pci_free_irq - free an interrupt allocated with pci_request_irq
* @dev: PCI device to operate on
* @nr: device-relative interrupt vector index (0-based).
* @dev_id: Device identity to free
* Remove an interrupt handler. The handler is removed and if the interrupt
* line is no longer in use by any driver it is disabled. The caller must
* ensure the interrupt is disabled on the device before calling this function.
* The function does not return until any executing interrupts for this IRQ
* have completed.
* This function must not be called from interrupt context.
void pci_free_irq(struct pci_dev *dev, unsigned int nr, void *dev_id)
kfree(free_irq(pci_irq_vector(dev, nr), dev_id));