media: uvcvideo: Introduce V4L2_META_FMT_UVC_MSXU_1_5

The UVC driver provides two metadata types V4L2_META_FMT_UVC, and
V4L2_META_FMT_D4XX. The only difference between the two of them is that
V4L2_META_FMT_UVC only copies PTS, SCR, size and flags, and
V4L2_META_FMT_D4XX copies the whole metadata section.

Now we only enable V4L2_META_FMT_D4XX for the Intel D4xx family of
devices, but it is useful to have the whole metadata payload for any
device where vendors include other metadata, such as the one described by
Microsoft:
https://learn.microsoft.com/en-us/windows-hardware/drivers/stream/mf-capture-metadata

This patch introduces a new format V4L2_META_FMT_UVC_MSXU_1_5, that is
identical to V4L2_META_FMT_D4XX.

Let the user enable this format with a quirk for now. This way they can
test if their devices provide useful metadata without rebuilding the
kernel. They can later contribute patches to auto-quirk their devices.
We will also work in methods to auto-detect devices compatible with this
new metadata format.

Suggested-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Hans de Goede <hansg@kernel.org>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Link: https://lore.kernel.org/r/20250707-uvc-meta-v8-4-ed17f8b1218b@chromium.org
Signed-off-by: Hans de Goede <hansg@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

Documentation/userspace-api/media/v4l/meta-formats.rst

@@ -20,6 +20,7 @@ These formats are used for the :ref:`metadata` interface only.
     metafmt-pisp-fe
     metafmt-rkisp1
     metafmt-uvc
+    metafmt-uvc-msxu-1-5
     metafmt-vivid
     metafmt-vsp1-hgo
     metafmt-vsp1-hgt

Documentation/userspace-api/media/v4l/metafmt-uvc-msxu-1-5.rst

@@ -0,0 +1,23 @@
+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+
+.. _v4l2-meta-fmt-uvc-msxu-1-5:
+
+***********************************
+V4L2_META_FMT_UVC_MSXU_1_5 ('UVCM')
+***********************************
+
+Microsoft(R)'s UVC Payload Metadata.
+
+
+Description
+===========
+
+V4L2_META_FMT_UVC_MSXU_1_5 buffers follow the metadata buffer layout of
+V4L2_META_FMT_UVC with the only difference that it includes all the UVC
+metadata in the `buffer[]` field, not just the first 2-12 bytes.
+
+The metadata format follows the specification from Microsoft(R) [1].
+
+.. _1:
+
+[1] https://docs.microsoft.com/en-us/windows-hardware/drivers/stream/uvc-extensions-1-5

MAINTAINERS

@@ -25837,6 +25837,7 @@ S:	Maintained
 W:	http://www.ideasonboard.org/uvc/
 T:	git git://linuxtv.org/media.git
 F:	Documentation/userspace-api/media/drivers/uvcvideo.rst
+F:	Documentation/userspace-api/media/v4l/metafmt-uvc-msxu-1-5.rst
 F:	Documentation/userspace-api/media/v4l/metafmt-uvc.rst
 F:	drivers/media/common/uvc.c
 F:	drivers/media/usb/uvc/

drivers/media/usb/uvc/uvc_metadata.c

@@ -189,6 +189,10 @@ void uvc_meta_init(struct uvc_device *dev)
 	    !WARN_ON(dev->info->meta_format == V4L2_META_FMT_UVC))
 		dev->meta_formats[i++] = dev->info->meta_format;
 
+	if (dev->quirks & UVC_QUIRK_MSXU_META &&
+	    !WARN_ON(dev->info->meta_format == V4L2_META_FMT_UVC_MSXU_1_5))
+		dev->meta_formats[i++] = V4L2_META_FMT_UVC_MSXU_1_5;
+
 	 /* IMPORTANT: for new meta-formats update UVC_MAX_META_DATA_FORMATS. */
 	dev->meta_formats[i++] = 0;
 }

drivers/media/usb/uvc/uvcvideo.h

@@ -77,6 +77,7 @@
 #define UVC_QUIRK_DISABLE_AUTOSUSPEND	0x00008000
 #define UVC_QUIRK_INVALID_DEVICE_SOF	0x00010000
 #define UVC_QUIRK_MJPEG_NO_EOF		0x00020000
+#define UVC_QUIRK_MSXU_META		0x00040000
 
 /* Format flags */
 #define UVC_FMT_FLAG_COMPRESSED		0x00000001

drivers/media/v4l2-core/v4l2-ioctl.c

@@ -1463,6 +1463,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
 	case V4L2_META_FMT_VSP1_HGO:	descr = "R-Car VSP1 1-D Histogram"; break;
 	case V4L2_META_FMT_VSP1_HGT:	descr = "R-Car VSP1 2-D Histogram"; break;
 	case V4L2_META_FMT_UVC:		descr = "UVC Payload Header Metadata"; break;
+	case V4L2_META_FMT_UVC_MSXU_1_5:	descr = "UVC MSXU Metadata"; break;
 	case V4L2_META_FMT_D4XX:	descr = "Intel D4xx UVC Metadata"; break;
 	case V4L2_META_FMT_VIVID:       descr = "Vivid Metadata"; break;
 	case V4L2_META_FMT_RK_ISP1_PARAMS:	descr = "Rockchip ISP1 3A Parameters"; break;

include/uapi/linux/videodev2.h

@@ -867,6 +867,7 @@ struct v4l2_pix_format {
 #define V4L2_META_FMT_VSP1_HGT    v4l2_fourcc('V', 'S', 'P', 'T') /* R-Car VSP1 2-D Histogram */
 #define V4L2_META_FMT_UVC         v4l2_fourcc('U', 'V', 'C', 'H') /* UVC Payload Header metadata */
 #define V4L2_META_FMT_D4XX        v4l2_fourcc('D', '4', 'X', 'X') /* D4XX Payload Header metadata */
+#define V4L2_META_FMT_UVC_MSXU_1_5  v4l2_fourcc('U', 'V', 'C', 'M') /* UVC MSXU metadata */
 #define V4L2_META_FMT_VIVID	  v4l2_fourcc('V', 'I', 'V', 'D') /* Vivid Metadata */
 
 /* Vendor specific - used for RK_ISP1 camera sub-system */