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From:   Ricardo Ribalda <ribalda@chromium.org>
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        tfiga@chromium.org
Cc:     Ricardo Ribalda <ribalda@chromium.org>
Subject: [PATCH v7 10/17] media: uvcvideo: Increase the size of UVC_METADATA_BUF_SIZE
Date:   Thu, 18 Mar 2021 21:29:21 +0100
Message-Id: <20210318202928.166955-11-ribalda@chromium.org>
In-Reply-To: <20210318202928.166955-1-ribalda@chromium.org>
References: <20210318202928.166955-1-ribalda@chromium.org>
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Hans has discovered that in his test device, for the H264 format
bytesused goes up to about 570, for YUYV it will actually go up
to a bit over 5000 bytes, and for MJPG up to about 2706 bytes.

We should also, according to V4L2_META_FMT_UVC docs, drop headers when
the buffer is full.

Credit-to: Hans Verkuil <hverkuil@xs4all.nl>
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
 drivers/media/usb/uvc/uvc_video.c | 8 +++++---
 drivers/media/usb/uvc/uvcvideo.h  | 2 +-
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index 25fd8aa23529..ea2903dc3252 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -1244,11 +1244,13 @@ static void uvc_video_decode_meta(struct uvc_streaming *stream,
 	if (!meta_buf || length == 2)
 		return;
 
+	/*
+	 * According to V4L2_META_FMT_UVC docs, we should drop headers when
+	 * the buffer is full.
+	 */
 	if (meta_buf->length - meta_buf->bytesused <
-	    length + sizeof(meta->ns) + sizeof(meta->sof)) {
-		meta_buf->error = 1;
+	    length + sizeof(meta->ns) + sizeof(meta->sof))
 		return;
-	}
 
 	has_pts = mem[1] & UVC_STREAM_PTS;
 	has_scr = mem[1] & UVC_STREAM_SCR;
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index b81d3f65e52e..a26bbec8d37b 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -527,7 +527,7 @@ struct uvc_stats_stream {
 	unsigned int max_sof;		/* Maximum STC.SOF value */
 };
 
-#define UVC_METADATA_BUF_SIZE 1024
+#define UVC_METADATA_BUF_SIZE 10240
 
 /**
  * struct uvc_copy_op: Context structure to schedule asynchronous memcpy
-- 
2.31.0.rc2.261.g7f71774620-goog