From 8a652a17e3c005dcdae31b6c8fdf14382a29cbbe Mon Sep 17 00:00:00 2001 From: Adam Goode Date: Sun, 23 Aug 2020 03:21:33 +0200 Subject: [PATCH] media: uvcvideo: Ensure all probed info is returned to v4l2 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 Signed-off-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab --- drivers/media/usb/uvc/uvc_v4l2.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c index 0335e69..5e6f315 100644 --- a/drivers/media/usb/uvc/uvc_v4l2.c +++ b/drivers/media/usb/uvc/uvc_v4l2.c @@ -247,11 +247,41 @@ 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 = uvc_v4l2_get_bytesperline(format, frame); fmt->fmt.pix.sizeimage = probe->dwMaxVideoFrameSize; + fmt->fmt.pix.pixelformat = format->fcc; fmt->fmt.pix.colorspace = format->colorspace; if (uvc_format != NULL) -- 2.7.4