linux-kernel - [PATCH v6 4/4] media: uvcvideo: Auto-set UVC_QUIRK_MSXU

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Message-Id: <20250604-uvc-meta-v6-4-7141d48c322c@chromium.org>
Date: Wed, 04 Jun 2025 12:16:05 +0000
From: Ricardo Ribalda <ribalda@...omium.org>
To: Laurent Pinchart <laurent.pinchart@...asonboard.com>, 
 Hans de Goede <hdegoede@...hat.com>, 
 Mauro Carvalho Chehab <mchehab@...nel.org>, 
 Guennadi Liakhovetski <guennadi.liakhovetski@...el.com>, 
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: linux-media@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-usb@...r.kernel.org, Ricardo Ribalda <ribalda@...omium.org>, 
 Hans de Goede <hansg@...nel.org>
Subject: [PATCH v6 4/4] media: uvcvideo: Auto-set UVC_QUIRK_MSXU_META

If the camera supports the MSXU_CONTROL_METADATA control, auto set the
MSXU_META quirk.

Reviewed-by: Hans de Goede <hansg@...nel.org>
Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
---
 drivers/media/usb/uvc/uvc_metadata.c | 72 ++++++++++++++++++++++++++++++++++++
 include/linux/usb/uvc.h              |  3 ++
 2 files changed, 75 insertions(+)

diff --git a/drivers/media/usb/uvc/uvc_metadata.c b/drivers/media/usb/uvc/uvc_metadata.c
index df3f259271c675feb590c4534dad95b3b786f082..cd58427578ff413591b60abe0a210b90802dddc7 100644
--- a/drivers/media/usb/uvc/uvc_metadata.c
+++ b/drivers/media/usb/uvc/uvc_metadata.c
@@ -10,6 +10,7 @@
 #include <linux/list.h>
 #include <linux/module.h>
 #include <linux/usb.h>
+#include <linux/usb/uvc.h>
 #include <linux/videodev2.h>
 
 #include <media/v4l2-ioctl.h>
@@ -188,11 +189,82 @@ static const struct v4l2_file_operations uvc_meta_fops = {
 	.mmap = vb2_fop_mmap,
 };
 
+static const u8 uvc_msxu_guid[16] = UVC_GUID_MSXU_1_5;
+
+static struct uvc_entity *uvc_meta_find_msxu(struct uvc_device *dev)
+{
+	struct uvc_entity *entity;
+
+	list_for_each_entry(entity, &dev->entities, list) {
+		if (!memcmp(entity->guid, uvc_msxu_guid, sizeof(entity->guid)))
+			return entity;
+	}
+
+	return NULL;
+}
+
+#define MSXU_CONTROL_METADATA 0x9
+static int uvc_meta_detect_msxu(struct uvc_device *dev)
+{
+	u32 *data __free(kfree) = NULL;
+	struct uvc_entity *entity;
+	int ret;
+
+	entity = uvc_meta_find_msxu(dev);
+	if (!entity)
+		return 0;
+
+	/*
+	 * USB requires buffers aligned in a special way, simplest way is to
+	 * make sure that query_ctrl will work is to kmalloc() them.
+	 */
+	data = kmalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	/* Check if the metadata is already enabled. */
+	ret = uvc_query_ctrl(dev, UVC_GET_CUR, entity->id, dev->intfnum,
+			     MSXU_CONTROL_METADATA, data, sizeof(*data));
+	if (ret)
+		return 0;
+
+	if (*data) {
+		dev->quirks |= UVC_QUIRK_MSXU_META;
+		return 0;
+	}
+
+	/*
+	 * 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.
+	 */
+	ret = uvc_query_ctrl(dev, UVC_GET_MAX, entity->id, dev->intfnum,
+			     MSXU_CONTROL_METADATA, data, sizeof(*data));
+	if (ret || !*data)
+		return 0;
+
+	/*
+	 * If we can set MSXU_CONTROL_METADATA, the device will report
+	 * metadata.
+	 */
+	ret = uvc_query_ctrl(dev, UVC_SET_CUR, entity->id, dev->intfnum,
+			     MSXU_CONTROL_METADATA, data, sizeof(*data));
+	if (!ret)
+		dev->quirks |= UVC_QUIRK_MSXU_META;
+
+	return 0;
+}
+
 int uvc_meta_register(struct uvc_streaming *stream)
 {
 	struct uvc_device *dev = stream->dev;
 	struct video_device *vdev = &stream->meta.vdev;
 	struct uvc_video_queue *queue = &stream->meta.queue;
+	int ret;
+
+	ret = uvc_meta_detect_msxu(dev);
+	if (ret)
+		return ret;
 
 	stream->meta.format = V4L2_META_FMT_UVC;
 
diff --git a/include/linux/usb/uvc.h b/include/linux/usb/uvc.h
index bce95153e5a65613a710d7316fc17cf5462b5bce..ee19e9f915b8370c333c426dc1ee4202c7b75c5b 100644
--- a/include/linux/usb/uvc.h
+++ b/include/linux/usb/uvc.h
@@ -29,6 +29,9 @@
 #define UVC_GUID_EXT_GPIO_CONTROLLER \
 	{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
 	 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x03}
+#define UVC_GUID_MSXU_1_5 \
+	{0xdc, 0x95, 0x3f, 0x0f, 0x32, 0x26, 0x4e, 0x4c, \
+	 0x92, 0xc9, 0xa0, 0x47, 0x82, 0xf4, 0x3b, 0xc8}
 
 #define UVC_GUID_FORMAT_MJPEG \
 	{ 'M',  'J',  'P',  'G', 0x00, 0x00, 0x10, 0x00, \

-- 
2.50.0.rc0.604.gd4ff7b7c86-goog