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From: Michael Grzeschik <m.grzeschik@pengutronix.de>
Date: Wed, 14 Feb 2024 00:37:55 +0100
Subject: [PATCH 2/2] usb: gadget: uvc: mark incomplete frames with
 UVC_STREAM_ERR
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Message-Id: <20240214-uvc-error-tag-v1-2-37659a3877fe@pengutronix.de>
References: <20240214-uvc-error-tag-v1-0-37659a3877fe@pengutronix.de>
In-Reply-To: <20240214-uvc-error-tag-v1-0-37659a3877fe@pengutronix.de>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>, 
 Daniel Scally <dan.scally@ideasonboard.com>, 
 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, 
 Michael Grzeschik <m.grzeschik@pengutronix.de>

If an frame was transmitted incomplete to the host, we set the
UVC_STREAM_ERR bit in the header for the last request that is going
to be queued. This way the host will know that it should drop the
frame instead of trying to display the corrupted content.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
---
 drivers/usb/gadget/function/uvc_video.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
index c288aceee92ac..af99958e6abf8 100644
--- a/drivers/usb/gadget/function/uvc_video.c
+++ b/drivers/usb/gadget/function/uvc_video.c
@@ -35,6 +35,9 @@ uvc_video_encode_header(struct uvc_video *video, struct uvc_buffer *buf,
 
 	data[1] = UVC_STREAM_EOH | video->fid;
 
+	if (video->queue.flags & UVC_QUEUE_DROP_INCOMPLETE)
+		data[1] |= UVC_STREAM_ERR;
+
 	if (video->queue.buf_used == 0 && ts.tv_sec) {
 		/* dwClockFrequency is 48 MHz */
 		u32 pts = ((u64)ts.tv_sec * USEC_PER_SEC + ts.tv_nsec / NSEC_PER_USEC) * 48;

-- 
2.39.2