tree: https://git.kernel.org/pub/scm/linux/kernel/git/kbingham/rcar.git vsp1/v3u head: 15890c07a0b56cea8221557f4c28a2052c1b3d14 commit: 7708982fa60fe0d474f68d42d0354e1973df954d [17/69] drm: rcar-du: Add R-Car DSI driver config: arm64-randconfig-r034-20210519 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project ceb1ac9812cb0972cfa34cecc5e5704ae2a22063) 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 arm64 cross compiling tool for clang build # apt-get install binutils-aarch64-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/kbingham/rcar.git/commit/... git remote add rcar https://git.kernel.org/pub/scm/linux/kernel/git/kbingham/rcar.git git fetch --no-tags rcar vsp1/v3u git checkout 7708982fa60fe0d474f68d42d0354e1973df954d # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64 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 >>): int rcar_mipi_dsi_clk_enable(struct drm_bridge *bridge) ^ drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c:613:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int rcar_mipi_dsi_clk_enable(struct drm_bridge *bridge) ^ static void rcar_mipi_dsi_clk_disable(struct drm_bridge *bridge) ^ drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c:636:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void rcar_mipi_dsi_clk_disable(struct drm_bridge *bridge) ^ static 2 warnings generated. vim +/rcar_mipi_dsi_clk_enable +613 drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c 608 609 /* ----------------------------------------------------------------------------- 610 * Clock Setting 611 */ 612 614 { 615 struct rcar_mipi_dsi *mipi_dsi = bridge_to_rcar_mipi_dsi(bridge); 616 int ret; 617 618 reset_control_deassert(mipi_dsi->rstc); 619 620 ret = clk_prepare_enable(mipi_dsi->clocks.mod); 621 if (ret < 0) 622 return ret; 623 624 ret = clk_prepare_enable(mipi_dsi->clocks.dsi); 625 if (ret < 0) 626 return ret; 627 628 ret = rcar_mipi_dsi_startup(mipi_dsi); 629 if (ret < 0) 630 return ret; 631 632 return 0; 633 } 634 EXPORT_SYMBOL_GPL(rcar_mipi_dsi_clk_enable); 635 637 { 638 struct rcar_mipi_dsi *mipi_dsi = bridge_to_rcar_mipi_dsi(bridge); 639 640 rcar_mipi_dsi_shutdown(mipi_dsi); 641 642 /* Disable DSI clock and reset HW */ 643 clk_disable_unprepare(mipi_dsi->clocks.dsi); 644 645 clk_disable_unprepare(mipi_dsi->clocks.mod); 646 647 reset_control_assert(mipi_dsi->rstc); 648 } 649 EXPORT_SYMBOL_GPL(rcar_mipi_dsi_clk_disable); 650 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org