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From:   Ai Chao <aichao@kylinos.cn>
To:     laurent.pinchart@ideasonboard.com, mchehab@kernel.org,
        ribalda@chromium.org
Cc:     linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        Ai Chao <aichao@kylinos.cn>
Subject: [PATCH v3] media: uvcvideo: Fix bandwidth error for Alcor camera
Date:   Fri, 18 Nov 2022 10:23:02 +0800
Message-Id: <20221118022302.112121-1-aichao@kylinos.cn>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

For Alcor Corp. Slave camera(1b17:6684/2017:0011), 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. For some device, device requested 2752512
 B/frame bandwidth. For some device, device requested 3072
 B/frame bandwidth. so we check the dwMaxPayloadTransferSize
 fields,if it large than 0x1000, reset dwMaxPayloadTransferSize
to 1024, and the camera preview normally.

Signed-off-by: Ai Chao <aichao@kylinos.cn>

---
change for v3
- Add VID/PID 2017:0011

change for v2
- Used usb_match_one_id to check VID and PID
---
---
 drivers/media/usb/uvc/uvc_video.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index d2eb9066e4dc..1260800ef8bd 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -135,6 +135,10 @@ static void uvc_fixup_video_ctrl(struct uvc_streaming *stream,
 	static const struct usb_device_id elgato_cam_link_4k = {
 		USB_DEVICE(0x0fd9, 0x0066)
 	};
+	static const struct usb_device_id alcor_corp_slave_cam = {
+		USB_DEVICE(0x1b17, 0x6684),
+		USB_DEVICE(0x2017, 0x0011),
+	};
 	struct uvc_format *format = NULL;
 	struct uvc_frame *frame = NULL;
 	unsigned int i;
@@ -234,6 +238,13 @@ 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) &&
+	     usb_match_one_id(stream->dev->intf, &alcor_corp_slave_cam)) {
+		ctrl->dwMaxPayloadTransferSize = 1024;
+	}
 }
 
 static size_t uvc_video_ctrl_size(struct uvc_streaming *stream)
-- 
2.25.1