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From: Michael Grzeschik <m.grzeschik@pengutronix.de>
Date: Wed, 14 Feb 2024 00:37:54 +0100
Subject: [PATCH 1/2] usb: gadget: uvc: dont drop frames if zero length
 packages are late
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Message-Id: <20240214-uvc-error-tag-v1-1-37659a3877fe@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 the request that was missed was zero bytes long, it
is likely that the overall transferred frame was not affected.
So don't flag the frame incomplete in that case.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
---
 drivers/usb/gadget/function/uvc_video.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
index dd3241fc6939d..c288aceee92ac 100644
--- a/drivers/usb/gadget/function/uvc_video.c
+++ b/drivers/usb/gadget/function/uvc_video.c
@@ -397,7 +397,8 @@ uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
 
 	case -EXDEV:
 		uvcg_dbg(&video->uvc->func, "VS request missed xfer.\n");
-		queue->flags |= UVC_QUEUE_DROP_INCOMPLETE;
+		if (req->length != 0)
+			queue->flags |= UVC_QUEUE_DROP_INCOMPLETE;
 		break;
 
 	case -ESHUTDOWN:	/* disconnect from host. */

-- 
2.39.2