From 2c4d9de8ab1434336248bbc01ee8e64d7e6b8a4f Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Thu, 10 Dec 2009 21:19:31 -0300 Subject: V4L/DVB (13829): uvcvideo: Fix alternate setting selection in isochronous mode Unlike assumed by the driver, alternate settings are not sorted by endpoint max packet size. Iterate over all alternate settings to find the one with the smallest compatible max packet size. Signed-off-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/uvc/uvc_video.c | 31 ++++++++++++++++++++++--------- 1 file changed, 22 insertions(+), 9 deletions(-) (limited to 'drivers/media/video/uvc/uvc_video.c') 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], -- cgit v1.2.3