Commit 5e3be666 authored Aug 25, 2021 by Barry Song Committed by Bjorn Helgaas Oct 18, 2021

PCI: Document /sys/bus/pci/devices/.../irq

Document /sys/bus/pci/devices/.../irq.

This file contains the IRQ of the INTx interrupt (or zero if the device
doesn't support INTx interrupts).

If the device has enabled MSI (not MSI-X), it contains the first MSI IRQ
instead.  This is a historical mistake because devices may support several
MSI or MSI-X vectors, and this file can't contain them all.  But we
preserve this behavior to avoid breaking userspace.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20210825102636.52757-2-21cnbao@gmail.com


Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent e4e737bb

Documentation/ABI/testing/sysfs-bus-pci

+11 −0

Original line number	Diff line number	Diff line
		@@ -96,6 +96,17 @@ Description:
		This attribute indicates the mode that the irq vector named by
		the file is in (msi vs. msix)

		What: /sys/bus/pci/devices/.../irq
		Date: August 2021
		Contact: Linux PCI developers <linux-pci@vger.kernel.org>
		Description:
		If a driver has enabled MSI (not MSI-X), "irq" contains the
		IRQ of the first MSI vector. Otherwise "irq" contains the
		IRQ of the legacy INTx interrupt.

		"irq" being set to 0 indicates that the device isn't
		capable of generating legacy INTx interrupts.

		What: /sys/bus/pci/devices/.../remove
		Date: January 2009
		Contact: Linux PCI developers <linux-pci@vger.kernel.org>