This patch exports the link-speed (in Mbps) and duplex of an interface
via sysfs. This eliminates the need to use ethtool just to check the
link-speed. Not requiring 'ethtool' and not relying on the SIOCETHTOOL
ioctl should be helpful in an embedded environment where space is at a
premium as well.
NOTE: This patch also intentionally allows non-root users to check the link
speed and duplex -- something not possible with ethtool.
Here's some sample output:
# cat /sys/class/net/eth0/speed
100
# cat /sys/class/net/eth0/duplex
half
# ethtool eth0
Settings for eth0:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: Not reported
Advertised auto-negotiation: No
Speed: 100Mb/s
Duplex: Half
Port: Twisted Pair
PHYAD: 1
Transceiver: internal
Auto-negotiation: off
Supports Wake-on: g
Wake-on: g
Current message level: 0x000000ff (255)
Link detected: yes
Signed-off-by: David S. Miller <davem@davemloft.net>
d519e17e2d