Linux网卡异常问题：ethernet eth0: no PHY
平台：IMX6Q
系统：Linux V3.14.28
异常日志信息如下：
Configuring network interfaces... [ 7.228356] fec 2188000.ethernet eth0: no PHY, assuming direct connection to switch [ 7.236055] libphy: PHY fixed-0:00 not found [ 7.240334] fec 2188000.ethernet eth0: could not attach to PHY ifconfig: SIOCSIFFLAGS: No such device [ 7.261377] fec 2188000.ethernet eth0: no PHY, assuming direct connection to switch [ 7.269110] libphy: PHY fixed-0:00 not found [ 7.273390] fec 2188000.ethernet eth0: could not attach to PHY ifconfig: SIOCSIFFLAGS: No such device
route: SIOCADDRT: Network is unreachable
这个总是说找不到phy，但是我ifconfig -a 有能找到eth0
root@M6708-T:~# ifconfig -a can0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 NOARP MTU:16 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:10 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:142 can1 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 NOARP MTU:16 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:10 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:143 eth0 Link encap:Ethernet HWaddr 00:14:97:1A:2A:28 inet addr:192.168.1.136 Bcast:192.168.1.255 Mask:255.255.255.0 BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:10 errors:0 dropped:0 overruns:0 frame:0 TX packets:10 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:700 (700.0 B) TX bytes:700 (700.0 B) sit0 Link encap:IPv6-in-IPv4 NOARP MTU:1480 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
解决办法：
网卡分为两个层次：MAC+PHY 一般说来，MAC就是网络控制器，如果该驱动OK，就能看到ifconfig信息； PHY是物理层，负责发送和传输的底层，如果PHY发生问题，ifconfig同样有信息，只有up时才会连接PHY。 MAC和PHY通过MII接口传输以太网数据，通过MDIO接口访问PHY的配置寄存器。 PHY连不上 第一可能是硬件问题，拿给做硬件的，检查一下PHY结果所有信号都很正常。。。。
待更新。
