[PATCH v2 2/2] Documentation: ABI: sysfs-bus-pci: Add description for IRQ entry

[Barry Song]

From: Barry Song <song.bao.hua@xxxxxxxxxxxxx>

/sys/bus/pci/devices/.../irq has been there for many years but it
has never been documented. This patch is trying to document it.

Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Barry Song <song.bao.hua@xxxxxxxxxxxxx>
---
 Documentation/ABI/testing/sysfs-bus-pci | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index 793cbb7..8d42385 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -96,6 +96,14 @@ 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:	Barry Song <song.bao.hua@xxxxxxxxxxxxx>
+Description:
+		Historically this attribute represent the IRQ line which runs
+		from the PCI device to the Interrupt controller. With MSI and
+		MSI-X, this attribute is the first IRQ number of IRQ vectors.
+
 What:		/sys/bus/pci/devices/.../remove
 Date:		January 2009
 Contact:	Linux PCI developers <linux-pci@xxxxxxxxxxxxxxx>
-- 
1.8.3.1