V4L/DVB (11835): uvcvideo: Parse frame descriptors with non-continuous indexes.

The UVC specification requires frame descriptors indexes to range from 1 to
the number of frame descriptors. At least some Hercules Dualpix Infinite
webcams erroneously use non-continuous index ranges. Make the driver support
them.
Signed-off-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/uvc/uvc_driver.c

@@ -289,10 +289,8 @@ static int uvc_parse_format(struct uvc_device *dev,
 	struct uvc_format_desc *fmtdesc;
 	struct uvc_frame *frame;
 	const unsigned char *start = buffer;
-	unsigned char *_buffer;
 	unsigned int interval;
 	unsigned int i, n;
-	int _buflen;
 	__u8 ftype;
 
 	format->type = buffer[2];
@@ -413,20 +411,11 @@ static int uvc_parse_format(struct uvc_device *dev,
 	buflen -= buffer[0];
 	buffer += buffer[0];
 
-	/* Count the number of frame descriptors to test the bFrameIndex
-	 * field when parsing the descriptors. We can't rely on the
-	 * bNumFrameDescriptors field as some cameras don't initialize it
-	 * properly.
-	 */
-	for (_buflen = buflen, _buffer = buffer;
-	     _buflen > 2 && _buffer[2] == ftype;
-	     _buflen -= _buffer[0], _buffer += _buffer[0])
-		format->nframes++;
-
 	/* Parse the frame descriptors. Only uncompressed, MJPEG and frame
 	 * based formats have frame descriptors.
 	 */
 	while (buflen > 2 && buffer[2] == ftype) {
+		frame = &format->frame[format->nframes];
 		if (ftype != VS_FRAME_FRAME_BASED)
 			n = buflen > 25 ? buffer[25] : 0;
 		else
@@ -441,16 +430,6 @@ static int uvc_parse_format(struct uvc_device *dev,
 			return -EINVAL;
 		}
 
-		if (buffer[3] - 1 >= format->nframes) {
-			uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming"
-			       "interface %d frame index %u out of range\n",
-			       dev->udev->devnum, alts->desc.bInterfaceNumber,
-			       buffer[3]);
-			return -EINVAL;
-		}
-
-		frame = &format->frame[buffer[3] - 1];
-
 		frame->bFrameIndex = buffer[3];
 		frame->bmCapabilities = buffer[4];
 		frame->wWidth = get_unaligned_le16(&buffer[5]);
@@ -507,6 +486,7 @@ static int uvc_parse_format(struct uvc_device *dev,
 			10000000/frame->dwDefaultFrameInterval,
 			(100000000/frame->dwDefaultFrameInterval)%10);
 
+		format->nframes++;
 		buflen -= buffer[0];
 		buffer += buffer[0];
 	}

drivers/media/video/uvc/uvc_video.c

@@ -65,7 +65,8 @@ static void uvc_fixup_video_ctrl(struct uvc_video_device *video,
 	struct uvc_streaming_control *ctrl)
 {
 	struct uvc_format *format;
-	struct uvc_frame *frame;
+	struct uvc_frame *frame = NULL;
+	unsigned int i;
 
 	if (ctrl->bFormatIndex <= 0 ||
 	    ctrl->bFormatIndex > video->streaming->nformats)
@@ -73,11 +74,15 @@ static void uvc_fixup_video_ctrl(struct uvc_video_device *video,
 
 	format = &video->streaming->format[ctrl->bFormatIndex - 1];
 
-	if (ctrl->bFrameIndex <= 0 ||
-	    ctrl->bFrameIndex > format->nframes)
-		return;
+	for (i = 0; i < format->nframes; ++i) {
+		if (format->frame[i].bFrameIndex == ctrl->bFrameIndex) {
+			frame = &format->frame[i];
+			break;
+		}
+	}
 
-	frame = &format->frame[ctrl->bFrameIndex - 1];
+	if (frame == NULL)
+		return;
 
 	if (!(format->flags & UVC_FMT_FLAG_COMPRESSED) ||
 	     (ctrl->dwMaxVideoFrameSize == 0 &&
@@ -1089,7 +1094,7 @@ int uvc_video_init(struct uvc_video_device *video)
 	/* Zero bFrameIndex might be correct. Stream-based formats (including
 	 * MPEG-2 TS and DV) do not support frames but have a dummy frame
 	 * descriptor with bFrameIndex set to zero. If the default frame
-	 * descriptor is not found, use the first avalable frame.
+	 * descriptor is not found, use the first available frame.
 	 */
 	for (i = format->nframes; i > 0; --i) {
 		frame = &format->frame[i-1];