tree: https://chromium.googlesource.com/chromiumos/third_party/kernel chromeos-4.14 head: 6f8992e59d85c46b0273cd2a3a9ab9cea8ddb4a1 commit: 999225d0e44ef997ab7f8965b2ffb262864dae35 [17/19] CHROMIUM: drm/evdi: Create sysfs link from evdi to its parent device and unlink on detach config: arm64-chromiumos-arm64-customedconfig-chrome-os:chromeos-4.14:1bf13820918c8ea2f8d01d646008dbc3c1cb5bee (attached as .config) compiler: aarch64-linux-gcc (GCC) 7.5.0 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 git remote add chrome-os https://chromium.googlesource.com/chromiumos/third_party/kernel git fetch --no-tags chrome-os chromeos-4.14 git checkout 999225d0e44ef997ab7f8965b2ffb262864dae35 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-7.5.0 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 errors (new ones prefixed by >>): drivers/gpu/drm/evdi/evdi_drv.c:83:6: error: no previous prototype for 'evdi_platform_device_is_free' [-Werror=missing-prototypes] bool evdi_platform_device_is_free(struct platform_device *pdev) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ void evdi_platform_device_link(struct platform_device *pdev, ^~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/evdi/evdi_drv.c: In function 'add_device_with_usb_path': drivers/gpu/drm/evdi/evdi_drv.c:442:8: error: variable 'itf_token' set but not used [-Werror=unused-but-set-variable] char *itf_token = NULL; ^~~~~~~~~ cc1: all warnings being treated as errors vim +/evdi_platform_device_link +95 drivers/gpu/drm/evdi/evdi_drv.c 82 84 { 85 struct evdi_platform_device_data *data = 86 (struct evdi_platform_device_data *)platform_get_drvdata(pdev); 87 struct evdi_device *evdi = data->drm_dev->dev_private; 88 89 if (evdi && !evdi_painter_is_connected(evdi) && 90 !data->symlinked) 91 return true; 92 return false; 93 } 94 96 struct device *parent) 97 { 98 struct evdi_platform_device_data *data = NULL; 99 int ret = 0; 100 101 if (!parent || !pdev) 102 return; 103 104 data = (struct evdi_platform_device_data *)platform_get_drvdata(pdev); 105 if (!evdi_platform_device_is_free(pdev)) { 106 EVDI_FATAL("Device is already attached can't symlink again\n"); 107 return; 108 } 109 110 ret = sysfs_create_link(&pdev->dev.kobj, &parent->kobj, "device"); 111 if (ret) { 112 EVDI_FATAL("Failed to create sysfs link to parent device\n"); 113 } else { 114 data->symlinked = true; 115 data->parent = parent; 116 } 117 } 118 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org