1 files changed, 22 insertions, 9 deletions

diff --git a/drivers/media/video/uvc/uvc_video.c b/drivers/media/video/uvc/uvc_video.c
index 9a9802830d41..e8cc0a9ddadd 100644
--- a/drivers/media/video/uvc/uvc_video.c
+++ b/drivers/media/video/uvc/uvc_video.c
@@ -924,10 +924,8 @@ static int uvc_init_video_bulk(struct uvc_streaming *stream,
 static int uvc_init_video(struct uvc_streaming *stream, gfp_t gfp_flags)
 {
         struct usb_interface *intf = stream->intf;
-        struct usb_host_interface *alts;
-        struct usb_host_endpoint *ep = NULL;
-        int intfnum = stream->intfnum;
-        unsigned int bandwidth, psize, i;
+        struct usb_host_endpoint *ep;
+        unsigned int i;
         int ret;
 
         stream->last_fid = -1;
@@ -936,6 +934,12 @@ static int uvc_init_video(struct uvc_streaming *stream, gfp_t gfp_flags)
         stream->bulk.payload_size = 0;
 
         if (intf->num_altsetting > 1) {
+                struct usb_host_endpoint *best_ep = NULL;
+                unsigned int best_psize = 3 * 1024;
+                unsigned int bandwidth;
+                unsigned int uninitialized_var(altsetting);
+                int intfnum = stream->intfnum;
+
                 /* Isochronous endpoint, select the alternate setting. */
                 bandwidth = stream->ctrl.dwMaxPayloadTransferSize;
 
@@ -949,6 +953,9 @@ static int uvc_init_video(struct uvc_streaming *stream, gfp_t gfp_flags)
                 }
 
                 for (i = 0; i < intf->num_altsetting; ++i) {
+                        struct usb_host_interface *alts;
+                        unsigned int psize;
+
                         alts = &intf->altsetting[i];
                         ep = uvc_find_endpoint(alts,
                                 stream->header.bEndpointAddress);
@@ -958,21 +965,27 @@ static int uvc_init_video(struct uvc_streaming *stream, gfp_t gfp_flags)
                         /* Check if the bandwidth is high enough. */
                         psize = le16_to_cpu(ep->desc.wMaxPacketSize);
                         psize = (psize & 0x07ff) * (1 + ((psize >> 11) & 3));
-                        if (psize >= bandwidth)
-                                break;
+                        if (psize >= bandwidth && psize <= best_psize) {
+                                altsetting = i;
+                                best_psize = psize;
+                                best_ep = ep;
+                        }
                 }
 
-                if (i >= intf->num_altsetting) {
+                if (best_ep == NULL) {
                         uvc_trace(UVC_TRACE_VIDEO, "No fast enough alt setting "
                                 "for requested bandwidth.\n");
                         return -EIO;
                 }
 
-                ret = usb_set_interface(stream->dev->udev, intfnum, i);
+                uvc_trace(UVC_TRACE_VIDEO, "Selecting alternate setting %u "
+                        "(%u B/frame bandwidth).\n", altsetting, best_psize);
+
+                ret = usb_set_interface(stream->dev->udev, intfnum, altsetting);
                 if (ret < 0)
                         return ret;
 
-                ret = uvc_init_video_isoc(stream, ep, gfp_flags);
+                ret = uvc_init_video_isoc(stream, best_ep, gfp_flags);
         } else {
                 /* Bulk endpoint, proceed to URB initialization. */
                 ep = uvc_find_endpoint(&intf->altsetting[0],