From: Adam Goode agoode@google.com
[ 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@google.com Signed-off-by: Laurent Pinchart laurent.pinchart@ideasonboard.com Signed-off-by: Mauro Carvalho Chehab mchehab+huawei@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 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;