From 8dbf9c7abefd5c1434a956d5c6b25e11183061a3 Mon Sep 17 00:00:00 2001
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Date: Fri, 10 Aug 2018 15:44:57 +0300
Subject: [PATCH] usb: gadget: uvc: Only halt video streaming endpoint in bulk mode
Git-commit: 8dbf9c7abefd5c1434a956d5c6b25e11183061a3
Patch-mainline: v4.20-rc1
References: bsc#1051510

When USB requests for video data fail to be submitted, the driver
signals a problem to the host by halting the video streaming endpoint.
This is only valid in bulk mode, as isochronous transfers have no
handshake phase and can't thus report a stall. The usb_ep_set_halt()
call returns an error when using isochronous endpoints, which we happily
ignore, but some UDCs complain in the kernel log. Fix this by only
trying to halt the endpoint in bulk mode.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Tested-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/usb/gadget/function/uvc_video.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
index a95c8e2364ed..2c9821ec836e 100644
--- a/drivers/usb/gadget/function/uvc_video.c
+++ b/drivers/usb/gadget/function/uvc_video.c
@@ -132,7 +132,9 @@ static int uvcg_video_ep_queue(struct uvc_video *video, struct usb_request *req)
 	ret = usb_ep_queue(video->ep, req, GFP_ATOMIC);
 	if (ret < 0) {
 		printk(KERN_INFO "Failed to queue request (%d).\n", ret);
-		usb_ep_set_halt(video->ep);
+		/* Isochronous endpoints can't be halted. */
+		if (usb_endpoint_xfer_bulk(video->ep->desc))
+			usb_ep_set_halt(video->ep);
 	}
 
 	return ret;
-- 
2.16.4