Re: [PATCH v4] media: uvcvideo: Fix bandwidth error for Alcor camera

From: Ricardo Ribalda
Date: Wed Nov 23 2022 - 03:20:24 EST


Hi Ai

On Tue, 22 Nov 2022 at 09:49, Ai Chao <aichao@xxxxxxxxxx> wrote:
>
> 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 fieldsby the fireware. For some device, it requested
nit:s/fireware/firmware/
> 2752512 B/frame bandwidth. For normally device, it requested 3072 or 1024
> 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@xxxxxxxxxx>
Reviewed-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
>
> ---
> change for v4
> - Change usb_match_one_id to usb_match_id
> - Modify the discription
>
> 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 | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> index d2eb9066e4dc..75bdd71d0e5a 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -135,6 +135,11 @@ 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(0x2017, 0x0011) },
> + { USB_DEVICE(0x1b17, 0x6684) },
> + { }
> + };
> struct uvc_format *format = NULL;
> struct uvc_frame *frame = NULL;
> unsigned int i;
> @@ -234,6 +239,13 @@ 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_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
>


--
Ricardo Ribalda