From 5e3be666f46b43169e80041657c4b63eaf1ae8de Mon Sep 17 00:00:00 2001 From: Barry Song Date: Wed, 25 Aug 2021 18:26:34 +0800 Subject: [PATCH] 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 Signed-off-by: Bjorn Helgaas Acked-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-bus-pci | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci index d4ae032..fef498c 100644 --- a/Documentation/ABI/testing/sysfs-bus-pci +++ b/Documentation/ABI/testing/sysfs-bus-pci @@ -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 +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 -- 2.7.4