From: Krzysztof Kozlowski <krzk@xxxxxxxxxx> commit 7be0d19c751b02db778ca95e3274d5ea7f31891c upstream. Selecting CONFIG_SAMSUNG_PM_DEBUG (depending on CONFIG_DEBUG_LL) but without CONFIG_MMU leads to build errors: arch/arm/plat-samsung/pm-debug.c: In function ‘s3c_pm_uart_base’: arch/arm/plat-samsung/pm-debug.c:57:2: error: implicit declaration of function ‘debug_ll_addr’ [-Werror=implicit-function-declaration] Fixes: 99b2fc2b8b40 ("ARM: SAMSUNG: Use debug_ll_addr() to get UART base address") Reported-by: kernel test robot <lkp@xxxxxxxxx> Signed-off-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20200910154150.3318-1-krzk@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/arm/plat-samsung/Kconfig | 1 + 1 file changed, 1 insertion(+) --- a/arch/arm/plat-samsung/Kconfig +++ b/arch/arm/plat-samsung/Kconfig @@ -241,6 +241,7 @@ config SAMSUNG_PM_DEBUG depends on PM && DEBUG_KERNEL depends on PLAT_S3C24XX || ARCH_S3C64XX || ARCH_S5PV210 depends on DEBUG_EXYNOS_UART || DEBUG_S3C24XX_UART || DEBUG_S3C2410_UART + depends on DEBUG_LL && MMU help Say Y here if you want verbose debugging from the PM Suspend and Resume code. See <file:Documentation/arm/samsung-s3c24xx/suspend.rst>