Re: [PATCH pci-next v1 0/1] PCI/sysfs: Expose PCIe device serial number

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Sat, 12 Jul 2025 18:17:12 -0700
Matthew Wood <thepacketgeek@gmail.com> wrote:

> Add a single sysfs read-only interface for reading PCIe device serial
> numbers from userspace in a programmatic way. This device attribute
> uses the same 2-byte dashed formatting as lspci serial number capability
> output:
> 
>     more /sys/devices/pci0000:c0/0000:c0:01.1/0000:c1:00.0/0000:c2:1f.0/0000:cc:00.0/device_serial_number
>     00-80-ee-00-00-00-41-80
> 

What is the use case for this? I can think of some possibilities but good to
see why you care here.


> Accompanying lspci output:
> 
>     sudo lspci -vvv -s cc:00.0
>         cc:00.0 Serial Attached SCSI controller: Broadcom / LSI PCIe Switch management endpoint (rev b0)
>             Subsystem: Broadcom / LSI Device 0144
>             ...
>             Capabilities: [100 v1] Device Serial Number 00-80-ee-00-00-00-41-80
>             ...
> 
> If a device doesn't support the serial number capability, userspace will receive
> an empty read:

Better if possible to not expose the sysfs attribute if no such capability.
We already have pcie_dev_attrs_are_visible() so easy to extend that.


> 
>     more /sys/devices/pci0000:00/0000:00:07.1/device_serial_number
>     echo $?
>     0
> 
> 
> Matthew Wood (1):
>   PCI/sysfs: Expose PCIe device serial number
> 
>  drivers/pci/pci-sysfs.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
>