From: Ricardo Ribalda Date: Wed, 16 Jul 2025 10:43:44 +0000 (+0000) Subject: media: uvcvideo: Fix comments in uvc_meta_detect_msxu X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e8e65d9237e590a953e17beb15bfd13dcfbe3ebf;p=thirdparty%2Fkernel%2Fstable.git media: uvcvideo: Fix comments in uvc_meta_detect_msxu The comments can be more precise. Let's fix them. Fixes: 6cb786f040ad ("media: uvcvideo: Auto-set UVC_QUIRK_MSXU_META") Cc: stable+noautosel@kernel.org # Coment change only, no need to backport Reviewed-by: Laurent Pinchart Signed-off-by: Ricardo Ribalda Signed-off-by: Hans de Goede Signed-off-by: Laurent Pinchart Signed-off-by: Hans Verkuil --- diff --git a/drivers/media/usb/uvc/uvc_metadata.c b/drivers/media/usb/uvc/uvc_metadata.c index 3b0b392895119..b0960f0553cfc 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));