linux内核外部驱动模块编译报错ERROR: "******" [drivers/**.ko] undefined!

我往linux内核里添加一个驱动模块，根据《linux设备驱动》第三版，修改Makefile如下：

   obj-m := GobiNet.o  
   GobiNet-objs :=  GobiUSBNet.o QMIDevice.o QMI.o  

/home/sylvain/Projects/android_gingerbread_realv210_ver_1_0/kernel  
   CHK     include/linux/version.h  
   CHK     include/generated/utsrelease.h  
make[1]: `include/generated/mach-types.h‘ is up to date.  
   CALL    scripts/checksyscalls.sh  
   CHK     include/generated/compile.h  
   LD      drivers/cell/OptionGobiNet/built-in.o  
   CC [M]  drivers/cell/OptionGobiNet/GobiUSBNet.o  
   CC [M]  drivers/cell/OptionGobiNet/QMIDevice.o  
   CC [M]  drivers/cell/OptionGobiNet/QMI.o  
   LD [M]  drivers/cell/OptionGobiNet/GobiNet.o  
   Kernel: arch/arm/boot/Image is ready  
   SHIPPED arch/arm/boot/compressed/lib1funcs.S  
   AS      arch/arm/boot/compressed/lib1funcs.o  
   LD      arch/arm/boot/compressed/vmlinux  
   OBJCOPY arch/arm/boot/zImage  
   Kernel: arch/arm/boot/zImage is ready       
   Building modules, stage 2.  
   MODPOST 5 modules  
ERROR: "usbnet_suspend" [drivers/cell/OptionGobiNet/GobiNet.ko] undefined!  
ERROR: "usbnet_resume" [drivers/cell/OptionGobiNet/GobiNet.ko] undefined!  
ERROR: "usbnet_disconnect" [drivers/cell/OptionGobiNet/GobiNet.ko] undefined!  
ERROR: "usbnet_probe" [drivers/cell/OptionGobiNet/GobiNet.ko] undefined!  
make[1]: *** [__modpost] Error 1  
make: *** [modules] Error 2   

我误解了错误信息，没有清楚ko生成过程。编译模块在链接过程中查找外部符号表，但并没有找到，因为该外部符号表并没有编译。

根据以上分析，我查看了外部符号在drivers/net/usb/usbnet.c文件，这就需要配置.config文件中设置CONFIG_USBNET=y。

希望对大家有所帮助。

英文地址：http://stackoverflow.com/questions/7812418/kernel-driver-external-modules-not-building-completely

linux内核外部驱动模块编译报错ERROR: "******" [drivers/**.ko] undefined!

原文：http://blog.csdn.net/liumangxiong/article/details/18710927