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 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> --- 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