Hi Dave, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: b0523c7b1c9d0edcd6c0fe6d2cb558a9ad5c60a8 commit: 26bfe3d0b227ab6d38692640b44ce48f2d857602 [2571/12912] ntb: intel: Add Icelake (gen4) support for Intel NTB config: x86_64-randconfig-r002-20200526 (attached as .config) compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 3393cc4cebf9969db94dc424b7a2b6195589c33b) 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 checkout 26bfe3d0b227ab6d38692640b44ce48f2d857602 # 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: kbuild test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>, old ones prefixed by <<): int intel_ntb4_link_disable(struct ntb_dev *ntb) ^ drivers/ntb/hw/intel/ntb_hw_gen4.c:449:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int intel_ntb4_link_disable(struct ntb_dev *ntb) ^ static 1 warning generated. vim +/intel_ntb4_link_disable +449 drivers/ntb/hw/intel/ntb_hw_gen4.c 448 450 { 451 struct intel_ntb_dev *ndev; 452 u32 ntb_cntl; 453 u16 lnkctl; 454 455 ndev = container_of(ntb, struct intel_ntb_dev, ntb); 456 457 dev_dbg(&ntb->pdev->dev, "Disabling link\n"); 458 459 /* clear the snoop bits */ 460 ntb_cntl = ioread32(ndev->self_mmio + ndev->reg->ntb_ctl); 461 ntb_cntl &= ~(NTB_CTL_E2I_BAR23_SNOOP | NTB_CTL_I2E_BAR23_SNOOP); 462 ntb_cntl &= ~(NTB_CTL_E2I_BAR45_SNOOP | NTB_CTL_I2E_BAR45_SNOOP); 463 iowrite32(ntb_cntl, ndev->self_mmio + ndev->reg->ntb_ctl); 464 465 lnkctl = ioread16(ndev->self_mmio + GEN4_LINK_CTRL_OFFSET); 466 lnkctl |= GEN4_LINK_CTRL_LINK_DISABLE; 467 iowrite16(lnkctl, ndev->self_mmio + GEN4_LINK_CTRL_OFFSET); 468 469 ndev->dev_up = 0; 470 471 return 0; 472 } 473 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org