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>
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>