X-Git-Url: https://git.ao2.it/libam7xxx.git/blobdiff_plain/9e24b798ba1376655756c55fd157661148799422..0ff36a0da0e0a1d8936e050231bfad118d92606b:/examples/am7xxx-modeswitch.c

diff --git a/examples/am7xxx-modeswitch.c b/examples/am7xxx-modeswitch.c
index fd2be6d..d5bd304 100644
--- a/examples/am7xxx-modeswitch.c
+++ b/examples/am7xxx-modeswitch.c
@@ -17,6 +17,7 @@
  */
 
 #include <stdio.h>
+#include <string.h>
 #include <errno.h>
 #include <libusb.h>
 
@@ -28,46 +29,86 @@
 
 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;
-	int transferred;
-	libusb_device_handle *usb_device = NULL;
-
+	libusb_device_handle *usb_device;
+	int current_configuration;
 	unsigned int len;
+	int transferred;
 
 	ret = libusb_init(NULL);
-	if (ret < 0)
+	if (ret < 0) {
+		fprintf(stderr, "libusb_init failed: %s\n",
+			libusb_error_name(ret));
 		goto out;
+	}
 
-	libusb_set_debug(NULL, 3);
+	libusb_set_debug(NULL, LIBUSB_LOG_LEVEL_INFO);
 
 	usb_device = libusb_open_device_with_vid_pid(NULL,
 						     AM7XXX_STORAGE_VID,
 						     AM7XXX_STORAGE_PID);
 	if (usb_device == NULL) {
-		fprintf(stderr, "cannot open the device: %d.\n", errno);
+		fprintf(stderr, "libusb_open failed: %s\n", strerror(errno));
 		ret = -errno;
 		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, "cannot set configuration.\n");
+		fprintf(stderr, "libusb_get_configuration failed: %s\n",
+			libusb_error_name(ret));
 		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, "cannot claim interface.\n");
+		fprintf(stderr, "libusb_claim_interface failed: %s\n",
+			libusb_error_name(ret));
+		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);