X-Git-Url: https://git.ao2.it/libam7xxx.git/blobdiff_plain/d584df17e94b4b6e0cf14a716cf5194811df2d92..c6f209c200de5b6e3611cdfe7003ad2e6f5f19e1:/examples/am7xxx-modeswitch.c

diff --git a/examples/am7xxx-modeswitch.c b/examples/am7xxx-modeswitch.c
index b431084..793130e 100644
--- a/examples/am7xxx-modeswitch.c
+++ b/examples/am7xxx-modeswitch.c
@@ -29,12 +29,13 @@
 
 static unsigned char switch_command[] =
 	"\x55\x53\x42\x43\x08\x70\x52\x89\x00\x00\x00\x00\x00\x00"
-	"\x0c\xff\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00";
+	"\x10\xff\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00";
 
 int main(void)
 {
 	int ret;
 	libusb_device_handle *usb_device;
+	int current_configuration;
 	unsigned int len;
 	int transferred;
 
@@ -56,27 +57,57 @@ int main(void)
 		goto out;
 	}
 
-	ret = libusb_set_configuration(usb_device, AM7XXX_STORAGE_CONFIGURATION);
+	current_configuration = -1;
+	ret = libusb_get_configuration(usb_device, &current_configuration);
 	if (ret < 0) {
-		fprintf(stderr, "libusb_set_configuration failed: %s\n",
+		fprintf(stderr, "libusb_get_configuration failed: %s\n",
 			libusb_error_name(ret));
-		fprintf(stderr, "Cannot set configuration %hhu\n",
-			AM7XXX_STORAGE_CONFIGURATION);
 		goto out_libusb_close;
 	}
 
+	if (current_configuration != AM7XXX_STORAGE_CONFIGURATION) {
+		ret = libusb_set_configuration(usb_device,
+					       AM7XXX_STORAGE_CONFIGURATION);
+		if (ret < 0) {
+			fprintf(stderr, "libusb_set_configuration failed: %s\n",
+				libusb_error_name(ret));
+			fprintf(stderr, "Cannot set configuration %d\n",
+				AM7XXX_STORAGE_CONFIGURATION);
+			goto out_libusb_close;
+		}
+	}
+
 	libusb_set_auto_detach_kernel_driver(usb_device, 1);
 
 	ret = libusb_claim_interface(usb_device, AM7XXX_STORAGE_INTERFACE);
 	if (ret < 0) {
 		fprintf(stderr, "libusb_claim_interface failed: %s\n",
 			libusb_error_name(ret));
-		fprintf(stderr, "Cannot claim interface %hhu\n",
+		fprintf(stderr, "Cannot claim interface %d\n",
 			AM7XXX_STORAGE_INTERFACE);
 		goto out_libusb_close;
 	}
 
+	/* Checking that the configuration has not changed, as suggested in
+	 * http://libusb.sourceforge.net/api-1.0/caveats.html
+	 */
+	current_configuration = -1;
+	ret = libusb_get_configuration(usb_device, &current_configuration);
+	if (ret < 0) {
+		fprintf(stderr, "libusb_get_configuration after claim failed: %s\n",
+			libusb_error_name(ret));
+		goto out_libusb_release_interface;
+	}
+
+	if (current_configuration != AM7XXX_STORAGE_CONFIGURATION) {
+		fprintf(stderr, "libusb configuration changed (expected: %d, current: %d\n",
+			AM7XXX_STORAGE_CONFIGURATION, current_configuration);
+		ret = -EINVAL;
+		goto out_libusb_release_interface;
+	}
+
 	len = sizeof(switch_command);
+
 	transferred = 0;
 	ret = libusb_bulk_transfer(usb_device, AM7XXX_STORAGE_OUT_EP,
 				   switch_command, len, &transferred, 0);