Hi Hao, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on robh/for-next] [also build test WARNING on linus/master v6.3-rc2 next-20230316] [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/Hao-Zhang/Coresight-Add-coresight-dummy-driver/20230316-112827 base: https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next patch link: https://lore.kernel.org/r/20230316032005.6509-2-quic_hazha%40quicinc.com patch subject: [PATCH v1 1/3] Coresight: Add coresight dummy driver config: arm-allyesconfig (https://download.01.org/0day-ci/archive/20230316/202303161702.oIkvUip5-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/140cd28ed9031020826cfb5e62e80e28f7504895 git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Hao-Zhang/Coresight-Add-coresight-dummy-driver/20230316-112827 git checkout 140cd28ed9031020826cfb5e62e80e28f7504895 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=arm olddefconfig COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash drivers/hwtracing/coresight/ If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot <lkp@xxxxxxxxx> | Link: https://lore.kernel.org/oe-kbuild-all/202303161702.oIkvUip5-lkp@xxxxxxxxx/ All warnings (new ones prefixed by >>): >> drivers/hwtracing/coresight/coresight-dummy.c:163:12: warning: no previous prototype for 'dummy_init' [-Wmissing-prototypes] 163 | int __init dummy_init(void) | ^~~~~~~~~~ >> drivers/hwtracing/coresight/coresight-dummy.c:169:13: warning: no previous prototype for 'dummy_exit' [-Wmissing-prototypes] 169 | void __exit dummy_exit(void) | ^~~~~~~~~~ vim +/dummy_init +163 drivers/hwtracing/coresight/coresight-dummy.c 162 > 163 int __init dummy_init(void) 164 { 165 return platform_driver_register(&dummy_driver); 166 } 167 module_init(dummy_init); 168 > 169 void __exit dummy_exit(void) 170 { 171 platform_driver_unregister(&dummy_driver); 172 } 173 module_exit(dummy_exit); 174 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests