media: uvcvideo: Implement dual stream quirk to fix loss of usb packets

Some cameras, such as the Sonix Technology Co. 292A, exhibit issues when
running two parallel streams, causing USB packets to be dropped when an
H.264 stream posts a keyframe while an MJPEG stream is running
simultaneously. This occasionally causes the driver to erroneously
output two consecutive JPEG images as a single frame.

To fix this, we inspect the buffer, and trigger a new frame when we
find an SOI.

Signed-off-by: Isaac Scott <[email protected]>
Reviewed-by: Ricardo Ribalda <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Laurent Pinchart <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>

Author: ijgs02

drivers/media/usb/uvc/uvc_video.c

@@ -20,6 +20,7 @@
 #include <linux/atomic.h>
 #include <linux/unaligned.h>
 
+#include <media/jpeg.h>
 #include <media/v4l2-common.h>
 
 #include "uvcvideo.h"
@@ -1142,6 +1143,7 @@ static void uvc_video_stats_stop(struct uvc_streaming *stream)
 static int uvc_video_decode_start(struct uvc_streaming *stream,
 		struct uvc_buffer *buf, const u8 *data, int len)
 {
+	u8 header_len;
 	u8 fid;
 
 	/*
@@ -1155,6 +1157,7 @@ static int uvc_video_decode_start(struct uvc_streaming *stream,
 		return -EINVAL;
 	}
 
+	header_len = data[0];
 	fid = data[1] & UVC_STREAM_FID;
 
 	/*
@@ -1236,9 +1239,31 @@ static int uvc_video_decode_start(struct uvc_streaming *stream,
 		return -EAGAIN;
 	}
 
+	/*
+	 * Some cameras, when running two parallel streams (one MJPEG alongside
+	 * another non-MJPEG stream), are known to lose the EOF packet for a frame.
+	 * We can detect the end of a frame by checking for a new SOI marker, as
+	 * the SOI always lies on the packet boundary between two frames for
+	 * these devices.
+	 */
+	if (stream->dev->quirks & UVC_QUIRK_MJPEG_NO_EOF &&
+	    (stream->cur_format->fcc == V4L2_PIX_FMT_MJPEG ||
+	    stream->cur_format->fcc == V4L2_PIX_FMT_JPEG)) {
+		const u8 *packet = data + header_len;
+
+		if (len >= header_len + 2 &&
+		    packet[0] == 0xff && packet[1] == JPEG_MARKER_SOI &&
+		    buf->bytesused != 0) {
+			buf->state = UVC_BUF_STATE_READY;
+			buf->error = 1;
+			stream->last_fid ^= UVC_STREAM_FID;
+			return -EAGAIN;
+		}
+	}
+
 	stream->last_fid = fid;
 
-	return data[0];
+	return header_len;
 }
 
 static inline enum dma_data_direction uvc_stream_dir(

drivers/media/usb/uvc/uvcvideo.h

@@ -76,6 +76,7 @@
 #define UVC_QUIRK_NO_RESET_RESUME	0x00004000
 #define UVC_QUIRK_DISABLE_AUTOSUSPEND	0x00008000
 #define UVC_QUIRK_INVALID_DEVICE_SOF	0x00010000
+#define UVC_QUIRK_MJPEG_NO_EOF		0x00020000
 
 /* Format flags */
 #define UVC_FMT_FLAG_COMPRESSED		0x00000001