diff options
Diffstat (limited to 'drivers/media/usb/uvc/uvc_video.c')
| -rw-r--r-- | drivers/media/usb/uvc/uvc_video.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c index a777b389a66e..e16464606b14 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -127,10 +127,37 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit, static void uvc_fixup_video_ctrl(struct uvc_streaming *stream, struct uvc_streaming_control *ctrl) { + static const struct usb_device_id elgato_cam_link_4k = { + USB_DEVICE(0x0fd9, 0x0066) + }; struct uvc_format *format = NULL; struct uvc_frame *frame = NULL; unsigned int i; + /* + * The response of the Elgato Cam Link 4K is incorrect: The second byte + * contains bFormatIndex (instead of being the second byte of bmHint). + * The first byte is always zero. The third byte is always 1. + * + * The UVC 1.5 class specification defines the first five bits in the + * bmHint bitfield. The remaining bits are reserved and should be zero. + * Therefore a valid bmHint will be less than 32. + * + * Latest Elgato Cam Link 4K firmware as of 2021-03-23 needs this fix. + * MCU: 20.02.19, FPGA: 67 + */ + if (usb_match_one_id(stream->dev->intf, &elgato_cam_link_4k) && + ctrl->bmHint > 255) { + u8 corrected_format_index = ctrl->bmHint >> 8; + + uvc_dbg(stream->dev, VIDEO, + "Correct USB video probe response from {bmHint: 0x%04x, bFormatIndex: %u} to {bmHint: 0x%04x, bFormatIndex: %u}\n", + ctrl->bmHint, ctrl->bFormatIndex, + 1, corrected_format_index); + ctrl->bmHint = 1; + ctrl->bFormatIndex = corrected_format_index; + } + for (i = 0; i < stream->nformats; ++i) { if (stream->format[i].index == ctrl->bFormatIndex) { format = &stream->format[i]; |