When CONFIG_NOP_USB_XCEIV is as 'm', usb_nop_xceiv_register() will be exported when the related module is loaded. So for built-in source code, still need use the empty one. Or it will can not pass compiling, the related error (for arm, with allmodconfig): arch/arm/mach-omap2/built-in.o: In function `omap3_evm_init': arch/arm/mach-omap2/board-omap3evm.c:703: undefined reference to `usb_nop_xceiv_register' Signed-off-by: Chen Gang <gang.chen@xxxxxxxxxxx> --- include/linux/usb/usb_phy_gen_xceiv.h | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/include/linux/usb/usb_phy_gen_xceiv.h b/include/linux/usb/usb_phy_gen_xceiv.h index f9a7e7b..8515958 100644 --- a/include/linux/usb/usb_phy_gen_xceiv.h +++ b/include/linux/usb/usb_phy_gen_xceiv.h @@ -12,7 +12,8 @@ struct usb_phy_gen_xceiv_platform_data { unsigned int needs_reset:1; }; -#if IS_ENABLED(CONFIG_NOP_USB_XCEIV) +#if IS_BUILTIN(CONFIG_NOP_USB_XCEIV) || \ + (IS_MODULE(CONFIG_NOP_USB_XCEIV) && defined(MODULE)) /* sometimes transceivers are accessed only through e.g. ULPI */ extern void usb_nop_xceiv_register(void); extern void usb_nop_xceiv_unregister(void); -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html