* Fix device identification for n800. patch from Robert Schuster

- Looks like n770 and n800 have different USB identifiers on the
    bootloader and the operating system.

* Print oops message and exit when the use has no permissions to
  access to the usb.

src/devices.c

@@ -24,6 +24,7 @@
 #include <stdlib.h>
 
 struct devices supported_devices[SUPPORTED_DEVICES] = {
+  { "FFFF", 0x000, 0x0000, 0x0000 },  // dummy
   { "unkn", 0x421, 0x3f00, 0x0000 },  // probably a development board
   { "n770", 0x421, 0x0105, 0x0001 },  // my n770 
   { "n800", 0x421, 0x04c3, 0x0001 },  // a n800 
@@ -31,17 +32,22 @@ struct devices supported_devices[SUPPORTED_DEVICES] = {
   { 0 }
 };
 
+/** Returns 0 when no device was found and a positive
+  * non-zero value when one was found.
+  *
+  * The return value is the index into the supported_devices
+  * array which denotes the device which was found.
+  */
 int is_valid_device(struct usb_device_descriptor *udd)
 {
 	int i;
-	struct devices ptr = supported_devices[0];
+	struct devices ptr = supported_devices[1];
 
-	for(i=0 ; ptr.vendor_id; ptr = supported_devices[++i])
+	for(i=1 ; ptr.vendor_id; ptr = supported_devices[++i])
 		if ((udd->idVendor  == ptr.vendor_id)
 		&&  (udd->idProduct == ptr.product_id)) {
-			printf("found %s (%04x:%04x)\n",
-				ptr.name, ptr.vendor_id, ptr.product_id);
-			return 1;
+                        D printf("found %s\n", supported_devices[i]);
+			return i;
 		}
 
 	return 0;
@@ -50,23 +56,29 @@ int is_valid_device(struct usb_device_descriptor *udd)
 void list_valid_devices()
 {
 	int i;
-	struct devices ptr = supported_devices[0];
+	struct devices ptr = supported_devices[1];
 
-	for(i=0; ptr.vendor_id; ptr = supported_devices[++i])
+	for(i=1; ptr.vendor_id; ptr = supported_devices[++i])
 		printf("%04x:%04x  %s\n", ptr.vendor_id, ptr.product_id, ptr.name);
 }
 
-int usb_device_found(struct usb_device_descriptor *udd)
+int usb_device_found(struct usb_device_descriptor *udd, struct devices *it_device)
 {
-	if (usb_find_busses() < 0) {
-		fprintf(stderr, "error: no usb busses found.\n");
-		exit(1);
-	} else {
-		if (usb_find_devices() < 0) {
-			fprintf(stderr, "error: no devices found.\n");
-			exit(1);
-		} else {
 	struct usb_bus *bus;
+        int dev_index = 0;
+
+	if (usb_find_busses() < 0) {
+		fprintf(stderr, "\nerror: no usb busses found.\n");
+		exit(1);
+	} else {
+		switch(usb_find_devices()) {
+		case -1:
+			fprintf(stderr, "\nerror: no devices found.\n");
+			exit(1);
+		case 0:
+			fprintf(stderr, "\noops: no permission to usb. got root?\n");
+			exit(1);
+		default:
 			for (bus = usb_busses; bus; bus = bus->next) {
 				struct usb_device *dev = bus->devices;
 				D printf("bus: \n");
@@ -75,8 +87,9 @@ int usb_device_found(struct usb_device_descriptor *udd)
 					D printf(" dev (%s) - ", dev->filename);
 					D printf("vendor: %04x product: %04x\n", udd->idVendor, udd->idProduct);
 
-					if (is_valid_device(udd)) {
+					if ((dev_index = is_valid_device(udd))) {
 						device = dev;
+                                                *it_device = supported_devices[dev_index];
 						return 1;
 					}
 				}

src/main.c

@@ -112,35 +112,69 @@ void unpack_fiasco_image(char *file)
 
 int connect_via_usb()
 {
-	int c=0;
         struct usb_device_descriptor udd;
+        struct devices it_device;
+	int    c = 0;
+	static char pbc[]={'/','-','\\', '|'};
+
 	// usb_set_debug(5);
 	usb_init();
 
-	while(!usb_device_found(&udd)) {
-		char pbc[]={'/','-','\\', '|'};
+        /* Tries to get access to the Internet Tablet and retries
+         * if any of the neccessary steps fail.
+         *
+         * Note: While a proper device may be found on the bus it may
+         * not be in the right state to be accessed (e.g. the Nokia is
+         * not in the boot stage any more).
+         */
+	while(!dev) {
 		usleep(0xc350); // 0.5s
+                
+                if(!usb_device_found(&udd, &it_device)) {
 			printf("\rWaiting for device... %c", pbc[++c%4]);
 			fflush(stdout);
+			continue;
 		}
 
-	/*/ open device */
-	dev = usb_open(device);
-	if (dev == NULL) {
+        	/* open device */
+        	if(!(dev = usb_open(device))) {
 	        	perror("usb_open");
                         return 1;
 	        }
-	// TODO
+
         	if ( usb_claim_interface(dev, 2) < 0) { // 2 or 0
-		perror("usb_claim_interface");
+	        	D perror("usb_claim_interface");
+
+                        // Something is broken if closing fails.
+                        if(usb_close(dev)) {
+                          perror("usb_close");
                           return 1;
                         }
 
+                        dev = NULL;
+
+                        // Try again later.
+                        continue;
+        	}
+
         	if (usb_set_altinterface(dev, 1) < 0) {
-		perror("usb_set_altinterface");
+	        	D perror("usb_set_altinterface");
+
+                        // Something is broken if closing fails.
+                        if(usb_close(dev)) {
+                          perror("usb_close");
                           return 1;
                         }
 
+                        dev = NULL;
+                        // Try again later.
+                        continue;
+        	}
+        }
+
+        printf("found %s (%04x:%04x)\n", it_device.name,
+		it_device.vendor_id, it_device.product_id);
+
 	/* go go go! */
 	while(get_status());
 
@@ -258,7 +292,10 @@ int main(int argc, char **argv)
 		return 0;
 	}
 
-	connect_via_usb();
+        if (connect_via_usb()) {
+                fprintf(stderr, "Cannot connect to device. It is possibly not in boot stage.\n");
+                return 0;
+        }
 
 	// if (info)
 	cmd_info("");

src/main.h

@@ -5,6 +5,8 @@
 #define _FILE_OFFSET_BITS 64
 #define _GNU_SOURCE
 
+// Forward declaration for use in function arguments.
+struct devices;
 
 int reverse_extract_pieces(char *dir);
 void flash_image(char *filename, char *piece, char *version);
@@ -22,7 +24,7 @@ extern struct usb_device *device;
 extern struct usb_dev_handle *dev;
 int is_valid_device(struct usb_device_descriptor *udd);
 void list_valid_devices();
-int usb_device_found(struct usb_device_descriptor *udd);
+int usb_device_found(struct usb_device_descriptor *udd, struct devices *it_device);
 int console(const char *device);
 int connect_via_usb();
 int console_prompt();
@@ -54,7 +56,8 @@ struct devices {
   unsigned short product_id;
   unsigned short flags;
 };
-#define SUPPORTED_DEVICES 5
+
+#define SUPPORTED_DEVICES 6
 extern struct devices supported_devices[SUPPORTED_DEVICES];
 
 extern int pcs_n;