diff options
| -rw-r--r-- | drivers/media/usb/uvc/uvc_metadata.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/media/usb/uvc/uvc_metadata.c b/drivers/media/usb/uvc/uvc_metadata.c index 3b0b39289511..b0960f0553cf 100644 --- a/drivers/media/usb/uvc/uvc_metadata.c +++ b/drivers/media/usb/uvc/uvc_metadata.c @@ -196,7 +196,10 @@ static int uvc_meta_detect_msxu(struct uvc_device *dev) if (!data) return -ENOMEM; - /* Check if the metadata is already enabled. */ + /* + * Check if the metadata is already enabled, or if the device always + * returns metadata. + */ ret = uvc_query_ctrl(dev, UVC_GET_CUR, entity->id, dev->intfnum, MSXU_CONTROL_METADATA, data, sizeof(*data)); if (ret) @@ -208,9 +211,11 @@ static int uvc_meta_detect_msxu(struct uvc_device *dev) } /* - * We have seen devices that require 1 to enable the metadata, others - * requiring a value != 1 and others requiring a value >1. Luckily for - * us, the value from GET_MAX seems to work all the time. + * Set the value of MSXU_CONTROL_METADATA to the value reported by + * GET_MAX to enable production of MSXU metadata. The GET_MAX request + * reports the maximum size of the metadata, if its value is 0 then MSXU + * metadata is not supported. For more information, see + * https://learn.microsoft.com/en-us/windows-hardware/drivers/stream/uvc-extensions-1-5#2229-metadata-control */ ret = uvc_query_ctrl(dev, UVC_GET_MAX, entity->id, dev->intfnum, MSXU_CONTROL_METADATA, data, sizeof(*data)); |