[PATCH v3 1/3] Documentation/ABI: document /sys/class/net/*/dev_port

Arseny Maslennikov
2018-09-03T16:13:14Z

The sysfs field was introduced 4 years ago along with fixes to various
drivers that erroneously used `dev_id' for that purpose, but it was not
properly documented anywhere.
See commit v3.14-rc3-739-g3f85944fe207.

Signed-off-by: Arseny Maslennikov <ar@cs.msu.ru>
---
Documentation/ABI/testing/sysfs-class-net | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-class-net b/Documentation/ABI/testing/sysfs-class-net
index 2f1788111cd9..ec2232f6a949 100644
--- a/Documentation/ABI/testing/sysfs-class-net
+++ b/Documentation/ABI/testing/sysfs-class-net
@@ -91,6 +91,24 @@ Description:
stacked (e.g: VLAN interfaces) but still have the same MAC
address as their parent device.

+What: /sys/class/net/<iface>/dev_port
+Date: February 2014
+KernelVersion: 3.15
+Contact: netdev@vger.kernel.org
+Description:
+ Indicates the port number of this network device, formatted
+ as a decimal value. Some NICs have multiple independent ports
+ on the same PCI bus, device and function. This attribute allows
+ userspace to distinguish the respective interfaces.
+
+ Note: some device drivers started to use 'dev_id' for this
+ purpose since long before 3.15 and have not adopted the new
+ attribute ever since. To query the port number, some tools look
+ exclusively at 'dev_port', while others only consult 'dev_id'.
+ If a network device has multiple client adapter ports as
+ described in the previous paragraph and does not set this
+ attribute to its port number, it's a kernel bug.
+
What: /sys/class/net/<iface>/dormant
Date: March 2006
KernelVersion: 2.6.17
--
2.19.0.rc1