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From:   Ai Chao <aichao@kylinos.cn>
To:     laurent.pinchart@ideasonboard.com, mchehab@kernel.org
Cc:     linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        aichao@kylinos.cn
Subject: [PATCH] media: uvcvideo: Fix bandwidth error for Alcor camera
Date:   Thu, 10 Nov 2022 16:12:59 +0800
Message-Id: <20221110081259.947269-1-aichao@kylinos.cn>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

For Alcor Corp. Slave camera(1b17:6684), it support to
output compressed video data, and it return a wrong
 dwMaxPayloadTransferSize fields. This is a fireware issue,
but the manufacturer cannot provide a const return fields
by the fireware. so we check the dwMaxPayloadTransferSize fields,
if it large than 0x1000, reset dwMaxPayloadTransferSize to 1024.

Signed-off-by: Ai Chao <aichao@kylinos.cn>
---
 drivers/media/usb/uvc/uvc_video.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index d2eb9066e4dc..49226c3f423c 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -234,6 +234,14 @@ static void uvc_fixup_video_ctrl(struct uvc_streaming *stream,
 
 		ctrl->dwMaxPayloadTransferSize = bandwidth;
 	}
+
+	/*Alcor Corp. Slave camera return wrong dwMaxPayloadTransferSize*/
+	if ((format->flags & UVC_FMT_FLAG_COMPRESSED) &&
+	    (ctrl->dwMaxPayloadTransferSize > 0x1000) &&
+	    (le16_to_cpu(stream->dev->udev->descriptor.idVendor) == 0x1b17) &&
+	    (le16_to_cpu(stream->dev->udev->descriptor.idProduct) == 0x6684)) {
+		ctrl->dwMaxPayloadTransferSize = 1024;
+	}
 }
 
 static size_t uvc_video_ctrl_size(struct uvc_streaming *stream)
-- 
2.25.1