我正在开发一个定制板，配备 iMX28 模块和 LAN9500A USB 转以太网控制器，不带用于网络接口的 EEPROM。操作系统是Linux（内核v3.16）。 LAN9500A 连接到带有集成磁性元件和 LED 的 RJ45 插孔。
我根据我的设计检查了 Microchip 的参考原理图。 http://ww1.microchip.com/downloads/en/DeviceDoc/9500a_sch.pdf
我可以看到 LAN9500A 已被检测到并且正确的驱动程序已加载...，
# dmesg | grep -i smsc
[ 1.549126] usbcore: registered new interface driver smsc95xx
[ 2.186356] smsc95xx v1.0.4
[ 2.258622] smsc95xx 1-1:1.0 eth2: register 'smsc95xx' at usb-ci_hdrc.1-1, smsc95xx USB 2.0 Ethernet, 62:94:6a:f1:ec:26
[ 9.588663] fec 800f0000.ethernet eth0: Freescale FEC PHY driver [SMSC LAN8710/LAN8720] (mii_bus:phy_addr=800f0000.etherne:00, irq=-1)
系统打开后，链接和活动 LED 指示灯亮起...
# ifconfig eth2 up
IPv6: ADDRCONF(NETDEV_UP): eth2: link is not ready
root@imx28evk:~# IPv6: ADDRCONF(NETDEV_CHANGE): eth2: link becomes ready
smsc95xx 1-1:1.0 eth2: link up, 100Mbps, full-duplex, lpa 0x4DE1
IPv6: eth2: IPv6 duplicate address fe80::fa:25ff:fe59:cf38 detected!
# ifconfig eth2 down
LED 仍然亮着...
# ifconfig eth2 up
smsc95xx 1-1:1.0 eth2: link up, 100Mbps, full-duplex, lpa 0xC5E1
# ifconfig eth2 down
LED 仍然亮着...
$ ifconfig eth2 up
现在 LED 熄灭了...
# ethtool eth2
Settings for eth2:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Advertised pause frame use: Symmetric Receive-only
Advertised auto-negotiation: Yes
Speed: 10Mb/s
Duplex: Half
Port: MII
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: pumbag
Wake-on: d
Current message level: 0x00000007 (7)
drv probe link
Link detected: no
# mii-tool eth2
eth2: no link
# ifconfig eth2 down
$ ifconfig eth2 up
smsc95xx 1-1:1.0 eth2: link up, 100Mbps, full-duplex, lpa 0xC5E1
LED 灯亮起
ethtool eth2
Settings for eth2:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Advertised pause frame use: Symmetric Receive-only
Advertised auto-negotiation: Yes
Link partner advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Link partner advertised pause frame use: Symmetric
Link partner advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: MII
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: pumbag
Wake-on: d
Current message level: 0x00000007 (7)
drv probe link
Link detected: yes
# mii-tool eth2
eth2: negotiated 1000baseT-HD flow-control, link ok
另一个问题是，当我从 RJ45 插座拔出并插入以太网电缆时，Linux 无法检测到它，...
还有其他人看过这个吗？我非常感谢您提供的任何帮助。
答案1
我意识到这个问题已经在一定程度上得到解决Linux 内核 3.16.48。