From c88e4017f109ac4c5e28663b817f21f56ffd1e47 Mon Sep 17 00:00:00 2001
From: Matthew Wilcox <matthew@wil.cx>
Date: Wed, 15 Dec 2010 15:44:05 -0500
Subject: [PATCH] --- yaml --- r: 227030 b: refs/heads/master c:
 89dc29051b626756e69db12f3ffb22e49a817bfe h: refs/heads/master v: v3

---
 [refs]                          |  2 +-
 trunk/drivers/usb/storage/uas.c | 37 ++++++++++++++++++++++++++-------
 2 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/[refs] b/[refs]
index e5acc2784ac1..f14245d12294 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 92a3f767f5cd079351ae04a337c40266e9c6048f
+refs/heads/master: 89dc29051b626756e69db12f3ffb22e49a817bfe
diff --git a/trunk/drivers/usb/storage/uas.c b/trunk/drivers/usb/storage/uas.c
index 06409a6ca2f4..52e5ec1b2e8a 100644
--- a/trunk/drivers/usb/storage/uas.c
+++ b/trunk/drivers/usb/storage/uas.c
@@ -582,6 +582,34 @@ static struct usb_device_id uas_usb_ids[] = {
 };
 MODULE_DEVICE_TABLE(usb, uas_usb_ids);
 
+static int uas_is_interface(struct usb_host_interface *intf)
+{
+	return (intf->desc.bInterfaceClass == USB_CLASS_MASS_STORAGE &&
+		intf->desc.bInterfaceSubClass == USB_SC_SCSI &&
+		intf->desc.bInterfaceProtocol == USB_PR_UAS);
+}
+
+static int uas_switch_interface(struct usb_device *udev,
+						struct usb_interface *intf)
+{
+	int i;
+
+	if (uas_is_interface(intf->cur_altsetting))
+		return 0;
+
+	for (i = 0; i < intf->num_altsetting; i++) {
+		struct usb_host_interface *alt = &intf->altsetting[i];
+		if (alt == intf->cur_altsetting)
+			continue;
+		if (uas_is_interface(alt))
+			return usb_set_interface(udev,
+						alt->desc.bInterfaceNumber,
+						alt->desc.bAlternateSetting);
+	}
+
+	return -ENODEV;
+}
+
 static void uas_configure_endpoints(struct uas_dev_info *devinfo)
 {
 	struct usb_host_endpoint *eps[4] = { };
@@ -655,13 +683,8 @@ static int uas_probe(struct usb_interface *intf, const struct usb_device_id *id)
 	struct uas_dev_info *devinfo;
 	struct usb_device *udev = interface_to_usbdev(intf);
 
-	if (id->bInterfaceProtocol == 0x50) {
-		int ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
-/* XXX: Shouldn't assume that 1 is the alternative we want */
-		int ret = usb_set_interface(udev, ifnum, 1);
-		if (ret)
-			return -ENODEV;
-	}
+	if (uas_switch_interface(udev, intf))
+		return -ENODEV;
 
 	devinfo = kmalloc(sizeof(struct uas_dev_info), GFP_KERNEL);
 	if (!devinfo)