[ Old code... ]
Hello Linus Walleij,
The patch 9ab12e88a0b4: "drm/tve200: Clean up panel bridging" from Sep 11, 2017, leads to the following Smatch static checker warning:
drivers/gpu/drm/tve200/tve200_drv.c:96 tve200_modeset_init() warn: missing error code here? '_dev_err()' failed. 'ret' = '0'
drivers/gpu/drm/tve200/tve200_drv.c 62 static int tve200_modeset_init(struct drm_device *dev) 63 { 64 struct drm_mode_config *mode_config; 65 struct tve200_drm_dev_private *priv = dev->dev_private; 66 struct drm_panel *panel; 67 struct drm_bridge *bridge; 68 int ret = 0; 69 70 drm_mode_config_init(dev); 71 mode_config = &dev->mode_config; 72 mode_config->funcs = &mode_config_funcs; 73 mode_config->min_width = 352; 74 mode_config->max_width = 720; 75 mode_config->min_height = 240; 76 mode_config->max_height = 576; 77 78 ret = drm_of_find_panel_or_bridge(dev->dev->of_node, 79 0, 0, &panel, &bridge); 80 if (ret && ret != -ENODEV) 81 return ret;
There is a return check here.
82 if (panel) { 83 bridge = drm_panel_bridge_add_typed(panel, 84 DRM_MODE_CONNECTOR_Unknown); 85 if (IS_ERR(bridge)) { 86 ret = PTR_ERR(bridge); 87 goto out_bridge; 88 } 89 } else { 90 /* 91 * TODO: when we are using a different bridge than a panel 92 * (such as a dumb VGA connector) we need to devise a different 93 * method to get the connector out of the bridge. 94 */ 95 dev_err(dev->dev, "the bridge is not a panel\n"); --> 96 goto out_bridge;
From reading this code without looking deeply into the context it looks
like ret can be either 0 or -ENODEV. Smatch does cross function analysis (sometimes badly) and says that drm_of_find_panel_or_bridge() only returns -EINVAL, zero, and -EPROBE_DEFER so it must be zero here.
97 } 98 99 ret = tve200_display_init(dev); 100 if (ret) { 101 dev_err(dev->dev, "failed to init display\n"); 102 goto out_bridge; 103 } 104 105 ret = drm_simple_display_pipe_attach_bridge(&priv->pipe, 106 bridge); 107 if (ret) { 108 dev_err(dev->dev, "failed to attach bridge\n"); 109 goto out_bridge; 110 } 111 112 priv->panel = panel; 113 priv->connector = drm_panel_bridge_connector(bridge); 114 priv->bridge = bridge; 115 116 dev_info(dev->dev, "attached to panel %s\n", 117 dev_name(panel->dev)); 118 119 ret = drm_vblank_init(dev, 1); 120 if (ret) { 121 dev_err(dev->dev, "failed to init vblank\n"); 122 goto out_bridge; 123 } 124 125 drm_mode_config_reset(dev); 126 drm_kms_helper_poll_init(dev); 127 128 goto finish; 129 130 out_bridge: 131 if (panel) 132 drm_panel_bridge_remove(bridge); 133 drm_mode_config_cleanup(dev); 134 finish: 135 return ret; 136 }
regards, dan carpenter