Thank you very much.
I have tried as following:
I tried "ifconfig" ,but always log running both plug into and plug out the network cable!
I tried "cat /sys/class/net/carrier" ,the log is no change when plug into and plug out the network cable!
I tested use ioctl(fd,SIOCGIFFLAGS,&ifreq) , it 's right only exec command "ifconfig eth0 down /up", but always "RUNNING" both plug into/out the network cable!
I checked my board's schematic diagram, maybe reason is not connect INT pin of phy to IRQ pin of p1010 ?