From 051cf386b5b7485c85787897177e70d599f503dd Mon Sep 17 00:00:00 2001
From: Solomon Peachy <pizza@shaftnet.org>
Date: Wed, 24 Jul 2013 20:54:14 -0400
Subject: [PATCH] common: Claim the device before calling the backend's
 query_serno() call.

---
 backend_common.c | 33 +++++++++++++++++++++++----------
 backend_common.h |  2 +-
 2 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/backend_common.c b/backend_common.c
index 2aefa27..e1c752f 100644
--- a/backend_common.c
+++ b/backend_common.c
@@ -27,7 +27,7 @@
 
 #include "backend_common.h"
 
-#define BACKEND_VERSION "0.16"
+#define BACKEND_VERSION "0.17"
 #ifndef URI_PREFIX
 #define URI_PREFIX "gutenprint+usb"
 #endif
@@ -38,12 +38,10 @@
 static char *get_device_id(struct libusb_device_handle *dev)
 {
 	int length;
-	int claimed = 0;
 	int iface = 0;
 	char *buf = malloc(ID_BUF_SIZE + 1);
 
-	claimed = libusb_kernel_driver_active(dev, iface);
-	if (claimed)
+	if (libusb_kernel_driver_active(dev, iface))
 		libusb_detach_kernel_driver(dev, iface);
 
 	libusb_claim_interface(dev, iface);
@@ -82,10 +80,7 @@ static char *get_device_id(struct libusb_device_handle *dev)
 
 done:
 	libusb_release_interface(dev, iface);
-#if 0
-	if (claimed)
-		libusb_attach_kernel_driver(dev, iface);
-#endif
+
 	return buf;
 }
 
@@ -159,8 +154,26 @@ static int print_scan_output(struct libusb_device *device,
 	if (desc->iSerialNumber) {
 		libusb_get_string_descriptor_ascii(dev, desc->iSerialNumber, serial, STR_LEN_MAX);
 		sanitize_string((char*)serial);
-	} else if (backend->query_serno) {
-		backend->query_serno(dev, (char*)serial, STR_LEN_MAX);
+	} else if (backend->query_serno) { /* XXX this is ... a cut-n-paste hack */
+		uint8_t endp_up, endp_down;
+		int i, iface = 0;
+		struct libusb_config_descriptor *config;
+
+		if (libusb_kernel_driver_active(dev, iface))
+			libusb_detach_kernel_driver(dev, iface);
+		libusb_claim_interface(dev, iface);
+		libusb_get_active_config_descriptor(device, &config);
+		for (i = 0 ; i < config->interface[0].altsetting[0].bNumEndpoints ; i++) {
+			if ((config->interface[0].altsetting[0].endpoint[i].bmAttributes & 3) == LIBUSB_TRANSFER_TYPE_BULK) {
+				if (config->interface[0].altsetting[0].endpoint[i].bEndpointAddress & LIBUSB_ENDPOINT_IN)
+					endp_up = config->interface[0].altsetting[0].endpoint[i].bEndpointAddress;
+				else
+					endp_down = config->interface[0].altsetting[0].endpoint[i].bEndpointAddress;				
+			}
+		}
+
+		backend->query_serno(dev, endp_up, endp_down, (char*)serial, STR_LEN_MAX);
+		libusb_release_interface(dev, iface);
 	}
 	
 	if (!strlen((char*)serial)) {
diff --git a/backend_common.h b/backend_common.h
index 31f1f71..0038763 100644
--- a/backend_common.h
+++ b/backend_common.h
@@ -115,7 +115,7 @@ struct dyesub_backend {
 	int  (*early_parse)(void *ctx, int data_fd);
 	int  (*read_parse)(void *ctx, int data_fd);
 	int  (*main_loop)(void *ctx, int copies);
-	int  (*query_serno)(struct libusb_device_handle *dev, char *buf, int buf_len);
+	int  (*query_serno)(struct libusb_device_handle *dev, uint8_t endp_up, uint8_t endp_down, char *buf, int buf_len);
 	struct device_id devices[];
 };