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authorRicardo Ribalda <ribalda@chromium.org>2025-07-16 10:43:44 +0000
committerHans Verkuil <hverkuil+cisco@kernel.org>2025-09-13 18:34:58 +0200
commite8e65d9237e590a953e17beb15bfd13dcfbe3ebf (patch)
tree6614d016edcd0bef46a37b5df8adade5cd6200a3 /drivers/media/usb
parentmedia: uvcvideo: Avoid variable shadowing in uvc_ctrl_cleanup_fh (diff)
downloadlinux-e8e65d9237e590a953e17beb15bfd13dcfbe3ebf.tar.gz
linux-e8e65d9237e590a953e17beb15bfd13dcfbe3ebf.zip
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 <laurent.pinchart@ideasonboard.com> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org> Signed-off-by: Hans de Goede <hansg@kernel.org> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
Diffstat (limited to 'drivers/media/usb')
-rw-r--r--drivers/media/usb/uvc/uvc_metadata.c13
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));