linux-kernel - [PATCH] usb: gadget: uvc: remove pause flag use

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Date:   Wed, 13 Apr 2022 14:24:02 -0500
From:   Dan Vacura <w36195@...orola.com>
To:     linux-usb@...r.kernel.org
Cc:     Michael Grzeschik <mgr@...gutronix.de>,
        Dan Vacura <w36195@...orola.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Felipe Balbi <balbi@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] usb: gadget: uvc: remove pause flag use

The pause flag doesn't appear to serve a purpose as it is possible for
the pump worker thread to not be running when new buffers are queued.
Before the following change was introduced: "43cd0023872e usb: gadget:
uvc_video: add worker to handle the frame pumping", the pause flag
status was discarded and never returned. This masked a current issues of
the userspace receiving non-zero values (considered unsuccessful) and
prevents trace_v4l2_qbuf() from being called.

Signed-off-by: Dan Vacura <w36195@...orola.com>
---
 drivers/usb/gadget/function/uvc_queue.c | 15 +--------------
 drivers/usb/gadget/function/uvc_queue.h |  1 -
 2 files changed, 1 insertion(+), 15 deletions(-)

diff --git a/drivers/usb/gadget/function/uvc_queue.c b/drivers/usb/gadget/function/uvc_queue.c
index d852ac9e47e7..8fd2f4a3dc4c 100644
--- a/drivers/usb/gadget/function/uvc_queue.c
+++ b/drivers/usb/gadget/function/uvc_queue.c
@@ -185,18 +185,7 @@ int uvcg_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
 
 int uvcg_queue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
 {
-	unsigned long flags;
-	int ret;
-
-	ret = vb2_qbuf(&queue->queue, NULL, buf);
-	if (ret < 0)
-		return ret;
-
-	spin_lock_irqsave(&queue->irqlock, flags);
-	ret = (queue->flags & UVC_QUEUE_PAUSED) != 0;
-	queue->flags &= ~UVC_QUEUE_PAUSED;
-	spin_unlock_irqrestore(&queue->irqlock, flags);
-	return ret;
+	return vb2_qbuf(&queue->queue, NULL, buf);
 }
 
 /*
@@ -362,8 +351,6 @@ struct uvc_buffer *uvcg_queue_head(struct uvc_video_queue *queue)
 	if (!list_empty(&queue->irqqueue))
 		buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 				       queue);
-	else
-		queue->flags |= UVC_QUEUE_PAUSED;
 
 	return buf;
 }
diff --git a/drivers/usb/gadget/function/uvc_queue.h b/drivers/usb/gadget/function/uvc_queue.h
index 05360a0767f6..42aaf8b227dd 100644
--- a/drivers/usb/gadget/function/uvc_queue.h
+++ b/drivers/usb/gadget/function/uvc_queue.h
@@ -43,7 +43,6 @@ struct uvc_buffer {
 
 #define UVC_QUEUE_DISCONNECTED		(1 << 0)
 #define UVC_QUEUE_DROP_INCOMPLETE	(1 << 1)
-#define UVC_QUEUE_PAUSED		(1 << 2)
 
 struct uvc_video_queue {
 	struct vb2_queue queue;
-- 
2.32.0