Hi Laurent, First bad commit (maybe != root cause): tree: git://linuxtv.org/pinchartl/media.git drm/du/compile-test head: 660500b4c311c0e60c5a05c603767cb4cac44751 commit: e112c91ed85ff80dd6731b9eb7ded6c34e0b854a [9/14] drm/imx/dcss: Enable COMPILE_TEST on all architectures config: i386-buildonly-randconfig-r004-20210804 (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): git remote add pinchartl-media git://linuxtv.org/pinchartl/media.git git fetch --no-tags pinchartl-media drm/du/compile-test git checkout e112c91ed85ff80dd6731b9eb7ded6c34e0b854a # save the attached .config to linux build tree make W=1 ARCH=i386 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All errors (new ones prefixed by >>): drivers/gpu/drm/imx/dcss/dcss-kms.c: In function 'dcss_kms_bridge_connector_init': >> drivers/gpu/drm/imx/dcss/dcss-kms.c:94:8: error: implicit declaration of function 'drm_bridge_attach' [-Werror=implicit-function-declaration] 94 | ret = drm_bridge_attach(encoder, bridge, NULL, | ^~~~~~~~~~~~~~~~~ >> drivers/gpu/drm/imx/dcss/dcss-kms.c:95:5: error: 'DRM_BRIDGE_ATTACH_NO_CONNECTOR' undeclared (first use in this function) 95 | DRM_BRIDGE_ATTACH_NO_CONNECTOR); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/imx/dcss/dcss-kms.c:95:5: note: each undeclared identifier is reported only once for each function it appears in cc1: some warnings being treated as errors vim +/drm_bridge_attach +94 drivers/gpu/drm/imx/dcss/dcss-kms.c 9021c317b77024f Laurentiu Palcu 2020-07-31 64 e7033bdfd43b852 Laurentiu Palcu 2020-07-31 65 static int dcss_kms_bridge_connector_init(struct dcss_kms_dev *kms) 9021c317b77024f Laurentiu Palcu 2020-07-31 66 { 9021c317b77024f Laurentiu Palcu 2020-07-31 67 struct drm_device *ddev = &kms->base; 9021c317b77024f Laurentiu Palcu 2020-07-31 68 struct drm_encoder *encoder = &kms->encoder; 9021c317b77024f Laurentiu Palcu 2020-07-31 69 struct drm_crtc *crtc = (struct drm_crtc *)&kms->crtc; 9021c317b77024f Laurentiu Palcu 2020-07-31 70 struct drm_panel *panel; 9021c317b77024f Laurentiu Palcu 2020-07-31 71 struct drm_bridge *bridge; 9021c317b77024f Laurentiu Palcu 2020-07-31 72 int ret; 9021c317b77024f Laurentiu Palcu 2020-07-31 73 9021c317b77024f Laurentiu Palcu 2020-07-31 74 ret = drm_of_find_panel_or_bridge(ddev->dev->of_node, 0, 0, 9021c317b77024f Laurentiu Palcu 2020-07-31 75 &panel, &bridge); 9021c317b77024f Laurentiu Palcu 2020-07-31 76 if (ret) 9021c317b77024f Laurentiu Palcu 2020-07-31 77 return ret; 9021c317b77024f Laurentiu Palcu 2020-07-31 78 9021c317b77024f Laurentiu Palcu 2020-07-31 79 if (!bridge) { 9021c317b77024f Laurentiu Palcu 2020-07-31 80 dev_err(ddev->dev, "No bridge found %d.\n", ret); 9021c317b77024f Laurentiu Palcu 2020-07-31 81 return -ENODEV; 9021c317b77024f Laurentiu Palcu 2020-07-31 82 } 9021c317b77024f Laurentiu Palcu 2020-07-31 83 9021c317b77024f Laurentiu Palcu 2020-07-31 84 encoder->possible_crtcs = drm_crtc_mask(crtc); 9021c317b77024f Laurentiu Palcu 2020-07-31 85 9021c317b77024f Laurentiu Palcu 2020-07-31 86 ret = drm_encoder_init(&kms->base, encoder, 9021c317b77024f Laurentiu Palcu 2020-07-31 87 &dcss_kms_simple_encoder_funcs, 9021c317b77024f Laurentiu Palcu 2020-07-31 88 DRM_MODE_ENCODER_NONE, NULL); 9021c317b77024f Laurentiu Palcu 2020-07-31 89 if (ret) { 9021c317b77024f Laurentiu Palcu 2020-07-31 90 dev_err(ddev->dev, "Failed initializing encoder %d.\n", ret); 9021c317b77024f Laurentiu Palcu 2020-07-31 91 return ret; 9021c317b77024f Laurentiu Palcu 2020-07-31 92 } 9021c317b77024f Laurentiu Palcu 2020-07-31 93 e7033bdfd43b852 Laurentiu Palcu 2020-07-31 @94 ret = drm_bridge_attach(encoder, bridge, NULL, e7033bdfd43b852 Laurentiu Palcu 2020-07-31 @95 DRM_BRIDGE_ATTACH_NO_CONNECTOR); fb8d617f8fd64f5 Laurent Pinchart 2021-03-23 96 if (ret < 0) e7033bdfd43b852 Laurentiu Palcu 2020-07-31 97 return ret; e7033bdfd43b852 Laurentiu Palcu 2020-07-31 98 e7033bdfd43b852 Laurentiu Palcu 2020-07-31 99 kms->connector = drm_bridge_connector_init(ddev, encoder); e7033bdfd43b852 Laurentiu Palcu 2020-07-31 100 if (IS_ERR(kms->connector)) { e7033bdfd43b852 Laurentiu Palcu 2020-07-31 101 dev_err(ddev->dev, "Unable to create bridge connector.\n"); e7033bdfd43b852 Laurentiu Palcu 2020-07-31 102 return PTR_ERR(kms->connector); e7033bdfd43b852 Laurentiu Palcu 2020-07-31 103 } e7033bdfd43b852 Laurentiu Palcu 2020-07-31 104 e7033bdfd43b852 Laurentiu Palcu 2020-07-31 105 drm_connector_attach_encoder(kms->connector, encoder); e7033bdfd43b852 Laurentiu Palcu 2020-07-31 106 e7033bdfd43b852 Laurentiu Palcu 2020-07-31 107 return 0; 9021c317b77024f Laurentiu Palcu 2020-07-31 108 } 9021c317b77024f Laurentiu Palcu 2020-07-31 109 :::::: The code at line 94 was first introduced by commit :::::: e7033bdfd43b85281b63d281b4dad3b9119f4427 drm/imx/dcss: use drm_bridge_connector API :::::: TO: Laurentiu Palcu :::::: CC: Lucas Stach --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org