Hi Biju, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on drm-tip/drm-tip] [also build test WARNING on next-20220726] [cannot apply to drm-intel/for-linux-next pinchartl-media/drm/du/next linus/master v5.19-rc8] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Biju-Das/Add-RCar-DU-lib-support/20220727-004502 base: git://anongit.freedesktop.org/drm/drm-tip drm-tip config: arm-randconfig-r035-20220724 (https://download.01.org/0day-ci/archive/20220727/202207270934.Cq65wqcE-lkp@xxxxxxxxx/config) compiler: arm-linux-gnueabi-gcc (GCC) 12.1.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/intel-lab-lkp/linux/commit/a703859b5858b11c89202731a2eba345dcbe1057 git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Biju-Das/Add-RCar-DU-lib-support/20220727-004502 git checkout a703859b5858b11c89202731a2eba345dcbe1057 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash drivers/gpu/drm/rcar-du/ If you fix the issue, kindly add following tag where applicable Reported-by: kernel test robot <lkp@xxxxxxxxx> All warnings (new ones prefixed by >>): >> drivers/gpu/drm/rcar-du/rcar_du_encoder.c:20:5: warning: no previous prototype for 'rcar_du_encoder_init' [-Wmissing-prototypes] 20 | int rcar_du_encoder_init(struct rcar_du_device *rcdu, | ^~~~~~~~~~~~~~~~~~~~ vim +/rcar_du_encoder_init +20 drivers/gpu/drm/rcar-du/rcar_du_encoder.c 4bf8e1962f91eed drivers/gpu/drm/rcar-du/rcar_du_lvds.c Laurent Pinchart 2013-06-19 15 6978f123776594b drivers/gpu/drm/rcar-du/rcar_du_encoder.c Laurent Pinchart 2013-06-15 16 /* ----------------------------------------------------------------------------- 6978f123776594b drivers/gpu/drm/rcar-du/rcar_du_encoder.c Laurent Pinchart 2013-06-15 17 * Encoder 6978f123776594b drivers/gpu/drm/rcar-du/rcar_du_encoder.c Laurent Pinchart 2013-06-15 18 */ 6978f123776594b drivers/gpu/drm/rcar-du/rcar_du_encoder.c Laurent Pinchart 2013-06-15 19 6978f123776594b drivers/gpu/drm/rcar-du/rcar_du_encoder.c Laurent Pinchart 2013-06-15 @20 int rcar_du_encoder_init(struct rcar_du_device *rcdu, -- 0-DAY CI Kernel Test Service https://01.org/lkp