Re: [PATCH] PCI/MSI: Clarify the irq sysfs ABI for PCI devices

[Greg KH]

On Sat, Aug 14, 2021 at 12:26:50AM +1200, Barry Song wrote:
> 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. Plus, irq ABI is very
> confusing at this moment especially for MSI and MSI-x cases. MSI sets irq
> to the first number in the vector, but MSI-X does nothing for this though
> it saves default_irq in msix_setup_entries(). Weird the saved default_irq
> for MSI-X is never used in pci_msix_shutdown(), which is quite different
> with pci_msi_shutdown(). Thus, this patch also moves to show the first IRQ
> number which is from the first msi_entry for MSI-X. Hopefully, this can
> make irq ABI more clear and more consistent.
> 
> Signed-off-by: Barry Song <song.bao.hua@xxxxxxxxxxxxx>
> ---
>  Documentation/ABI/testing/sysfs-bus-pci | 8 ++++++++
>  drivers/pci/msi.c                       | 6 ++++++
>  2 files changed, 14 insertions(+)

Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>