MTK modem使用cdc_ether驱动，使用udhcpc无法获取IP地址

yang-kiki

使用2.6.36内核，使用cdc_ether,usbserial驱动MTK modem。启动后，发现usb0接口并没有up，于是手动up。
拨号成功后，开启udhcpc。一直获取不到iP地址，于是使用tcpdump 抓包，发现不停的在发广播包。就是获取不到地址。
# tcpdump -i usb0
device usb0 entered promiscuous mode
tcpdump: WARNING: usb0: no IPv4 address assigned
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on usb0, link-type EN10MB (Ethernet), capture size 68 bytes
00:28:13.848500 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request [|bootp]
00:28:16.852220 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request [|bootp]
00:28:19.856220 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request [|bootp]
00:28:43.052240 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request [|bootp]
00:28:46.056200 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request [|bootp]
00:28:49.060200 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request [|bootp]
00:29:12.236240 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request [|bootp]
00:29:15.240200 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request [|bootp]

yang-kiki

竟然没人回答，看来还是得靠自己。

wickyl

某些modem需要初始化完成操作才能进入获取地址状态。
先确保初始化完成(at手册有说明)，信号OK。再试试。