platform: detect missing firmware on IFF_UP change

src/platform/nm-linux-platform.c

@@ -886,6 +886,14 @@ link_change (NMPlatform *platform, int ifindex, struct rtnl_link *change)
 
 	nle = rtnl_link_change (priv->nlh, rtnllink, change, 0);
 
+	/* When netlink returns this error, it usually means it failed to find
+	 * firmware for the device, especially on nm_platform_link_set_up ().
+	 * This is basically the same check as in the original code and could
+	 * potentially be improved.
+	 */
+	if (nle == -NLE_NOT_FOUND)
+		return NM_PLATFORM_ERROR_NO_FIRMWARE;
+
 	return refresh_object (platform, (struct nl_object *) rtnllink, nle);
 }
 

src/platform/nm-platform.c

@@ -177,6 +177,8 @@ nm_platform_get_error_msg (void)
 		return "object already exists";
 	case NM_PLATFORM_ERROR_NOT_SLAVE:
 		return "link not a slave";
+	case NM_PLATFORM_ERROR_NO_FIRMWARE:
+		return "firmware not found";
 	default:
 		return "invalid error number";
 	}

src/platform/nm-platform.h

@@ -43,6 +43,8 @@ typedef enum {
 	NM_PLATFORM_ERROR_EXISTS,
 	/* object is not a slave */
 	NM_PLATFORM_ERROR_NOT_SLAVE
+	/* firmware is not found */
+	NM_PLATFORM_ERROR_NO_FIRMWARE
 } NMPlatformError;
 
 typedef enum {