Hi Deren, FYI, the error/warning still remains. tree: https://chromium.googlesource.com/chromiumos/third_party/kernel chromeos-5.4 head: 35c5b82640fd5f825e85c5cc6d8f6101c24d817f commit: 5f94a0c31e951c4196789d4b377d3806ff5bd4d0 [33/69] FROMLIST: mt76: mt7921: introduce PCIe ASPM support (L0s/L1/L1ss) config: x86_64-randconfig-a006-20210620 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project e1adf90826a57b674eee79b071fb46c1f5683cd0) 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 # install x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu git remote add chrome-os https://chromium.googlesource.com/chromiumos/third_party/kernel git fetch --no-tags chrome-os chromeos-5.4 git checkout 5f94a0c31e951c4196789d4b377d3806ff5bd4d0 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): void mt7921_pci_enable_aspm(struct pci_dev *pdev) ^ drivers/net/wireless/mediatek/mt76/mt7921/pci.c:151:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void mt7921_pci_enable_aspm(struct pci_dev *pdev) ^ static 1 warning generated. vim +/mt7921_pci_enable_aspm +151 drivers/net/wireless/mediatek/mt76/mt7921/pci.c 150 152 { 153 mt7921_pci_config_L1ss(pdev, true); 154 mt7921_pci_config_L1(pdev, true); 155 } 156 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org