Patch "media: uvcvideo: Ensure all probed info is returned to v4l2" has been added to the 4.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    media: uvcvideo: Ensure all probed info is returned to v4l2

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     media-uvcvideo-ensure-all-probed-info-is-returned-to.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 57e4b3d24c887d9a50f8fe31c4eec0ca96503976
Author: Adam Goode <agoode@xxxxxxxxxx>
Date:   Sun Aug 23 03:21:33 2020 +0200

    media: uvcvideo: Ensure all probed info is returned to v4l2
    
    [ Upstream commit 8a652a17e3c005dcdae31b6c8fdf14382a29cbbe ]
    
    bFrameIndex and bFormatIndex can be negotiated by the camera during
    probing, resulting in the camera choosing a different format than
    expected. v4l2 can already accommodate such changes, but the code was
    not updating the proper fields.
    
    Without such a change, v4l2 would potentially interpret the payload
    incorrectly, causing corrupted output. This was happening on the
    Elgato HD60 S+, which currently always renegotiates to format 1.
    
    As an aside, the Elgato firmware is buggy and should not be renegotating,
    but it is still a valid thing for the camera to do. Both macOS and Windows
    will properly probe and read uncorrupted images from this camera.
    
    With this change, both qv4l2 and chromium can now read uncorrupted video
    from the Elgato HD60 S+.
    
    [Add blank lines, remove periods at the of messages]
    
    Signed-off-by: Adam Goode <agoode@xxxxxxxxxx>
    Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
    Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index 0e7d16fe84d42..a0a544628053d 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -242,11 +242,41 @@ static int uvc_v4l2_try_format(struct uvc_streaming *stream,
 	if (ret < 0)
 		goto done;
 
+	/* After the probe, update fmt with the values returned from
+	 * negotiation with the device.
+	 */
+	for (i = 0; i < stream->nformats; ++i) {
+		if (probe->bFormatIndex == stream->format[i].index) {
+			format = &stream->format[i];
+			break;
+		}
+	}
+
+	if (i == stream->nformats) {
+		uvc_trace(UVC_TRACE_FORMAT, "Unknown bFormatIndex %u\n",
+			  probe->bFormatIndex);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < format->nframes; ++i) {
+		if (probe->bFrameIndex == format->frame[i].bFrameIndex) {
+			frame = &format->frame[i];
+			break;
+		}
+	}
+
+	if (i == format->nframes) {
+		uvc_trace(UVC_TRACE_FORMAT, "Unknown bFrameIndex %u\n",
+			  probe->bFrameIndex);
+		return -EINVAL;
+	}
+
 	fmt->fmt.pix.width = frame->wWidth;
 	fmt->fmt.pix.height = frame->wHeight;
 	fmt->fmt.pix.field = V4L2_FIELD_NONE;
 	fmt->fmt.pix.bytesperline = format->bpp * frame->wWidth / 8;
 	fmt->fmt.pix.sizeimage = probe->dwMaxVideoFrameSize;
+	fmt->fmt.pix.pixelformat = format->fcc;
 	fmt->fmt.pix.colorspace = format->colorspace;
 	fmt->fmt.pix.priv = 0;