tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 92510a7fd93c64ca3e3564b041051e9a17860a65 commit: 394679649e9093adb63f8d8c4cedd10f6e80dd2d [14576/14788] drm/amdgpu/display: add support for multiple backlights config: x86_64-randconfig-a013-20210709 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 8d69635ed9ecf36fd0ca85906bfde17949671cbe) 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 # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commi... git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git fetch --no-tags linux-next master git checkout 394679649e9093adb63f8d8c4cedd10f6e80dd2d # 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 >>): if (dm->backlight_dev) ~~ ~~~~^~~~~~~~~~~~~ 1 warning generated. vim +857 drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c d38ceaf99ed015 Alex Deucher 2015-04-20 837 d38ceaf99ed015 Alex Deucher 2015-04-20 838 /* Call all ACPI methods here */ d38ceaf99ed015 Alex Deucher 2015-04-20 839 /** d38ceaf99ed015 Alex Deucher 2015-04-20 840 * amdgpu_acpi_init - init driver acpi support d38ceaf99ed015 Alex Deucher 2015-04-20 841 * d38ceaf99ed015 Alex Deucher 2015-04-20 842 * @adev: amdgpu_device pointer d38ceaf99ed015 Alex Deucher 2015-04-20 843 * d38ceaf99ed015 Alex Deucher 2015-04-20 844 * Verifies the AMD ACPI interfaces and registers with the acpi d38ceaf99ed015 Alex Deucher 2015-04-20 845 * notifier chain (all asics). d38ceaf99ed015 Alex Deucher 2015-04-20 846 * Returns 0 on success, error on failure. d38ceaf99ed015 Alex Deucher 2015-04-20 847 */ d38ceaf99ed015 Alex Deucher 2015-04-20 848 int amdgpu_acpi_init(struct amdgpu_device *adev) d38ceaf99ed015 Alex Deucher 2015-04-20 849 { f9b7f3703ff977 Alex Deucher 2021-05-25 850 struct amdgpu_atif *atif = &amdgpu_acpi_priv.atif; d38ceaf99ed015 Alex Deucher 2015-04-20 851 97d798b276e94a Alex Deucher 2020-05-05 852 #if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) || defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE) 9c27bc97aff8bb Ye Bin 2020-10-09 853 if (atif->notifications.brightness_change) { 97d798b276e94a Alex Deucher 2020-05-05 854 if (amdgpu_device_has_dc_support(adev)) { 97d798b276e94a Alex Deucher 2020-05-05 855 #if defined(CONFIG_DRM_AMD_DC) 97d798b276e94a Alex Deucher 2020-05-05 856 struct amdgpu_display_manager *dm = &adev->dm; 77bf762f8b3011 Alex Deucher 2021-05-19 @857 if (dm->backlight_dev) 394679649e9093 Alex Deucher 2021-07-08 858 atif->bd = dm->backlight_dev[0]; 97d798b276e94a Alex Deucher 2020-05-05 859 #endif 97d798b276e94a Alex Deucher 2020-05-05 860 } else { d38ceaf99ed015 Alex Deucher 2015-04-20 861 struct drm_encoder *tmp; d38ceaf99ed015 Alex Deucher 2015-04-20 862 d38ceaf99ed015 Alex Deucher 2015-04-20 863 /* Find the encoder controlling the brightness */ 4a580877bdcb83 Luben Tuikov 2020-08-24 864 list_for_each_entry(tmp, &adev_to_drm(adev)->mode_config.encoder_list, d38ceaf99ed015 Alex Deucher 2015-04-20 865 head) { d38ceaf99ed015 Alex Deucher 2015-04-20 866 struct amdgpu_encoder *enc = to_amdgpu_encoder(tmp); d38ceaf99ed015 Alex Deucher 2015-04-20 867 d38ceaf99ed015 Alex Deucher 2015-04-20 868 if ((enc->devices & (ATOM_DEVICE_LCD_SUPPORT)) && d38ceaf99ed015 Alex Deucher 2015-04-20 869 enc->enc_priv) { d38ceaf99ed015 Alex Deucher 2015-04-20 870 struct amdgpu_encoder_atom_dig *dig = enc->enc_priv; d38ceaf99ed015 Alex Deucher 2015-04-20 871 if (dig->bl_dev) { 97d798b276e94a Alex Deucher 2020-05-05 872 atif->bd = dig->bl_dev; d38ceaf99ed015 Alex Deucher 2015-04-20 873 break; d38ceaf99ed015 Alex Deucher 2015-04-20 874 } d38ceaf99ed015 Alex Deucher 2015-04-20 875 } d38ceaf99ed015 Alex Deucher 2015-04-20 876 } d38ceaf99ed015 Alex Deucher 2015-04-20 877 } 97d798b276e94a Alex Deucher 2020-05-05 878 } 97d798b276e94a Alex Deucher 2020-05-05 879 #endif f9b7f3703ff977 Alex Deucher 2021-05-25 880 adev->acpi_nb.notifier_call = amdgpu_acpi_event; f9b7f3703ff977 Alex Deucher 2021-05-25 881 register_acpi_notifier(&adev->acpi_nb); f9b7f3703ff977 Alex Deucher 2021-05-25 882 f9b7f3703ff977 Alex Deucher 2021-05-25 883 return 0; f9b7f3703ff977 Alex Deucher 2021-05-25 884 } f9b7f3703ff977 Alex Deucher 2021-05-25 885 :::::: The code at line 857 was first introduced by commit :::::: 77bf762f8b3011b2d00eb49098071952956da892 drm/amdgpu/acpi: unify ATCS handling (v3) :::::: TO: Alex Deucher <alexander.deucher(a)amd.com&gt; :::::: CC: Alex Deucher <alexander.deucher(a)amd.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org