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smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=sMC7xDym; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="sMC7xDym" Received: from pendragon.ideasonboard.com (81-175-209-231.bb.dnainternet.fi [81.175.209.231]) by perceval.ideasonboard.com (Postfix) with UTF8SMTPSA id 625B61B24; Mon, 14 Jul 2025 10:34:13 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1752482053; bh=bNqtFKKhIxtAE+9B1scbgn/0YjscZsM8E76sZWd1D54=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=sMC7xDymjfhpAP2CvItrJQBBC3UMPLX4+nrTXtbXY6G50QB0q98VOGxUNKUK+EE2h NzwoXyc66kfDINrwoW8yZGXnL28SS3w4Jv3XznJbmuJ0TJNmoWxFDlRWXo+kLWiyRK MIYxoUHh6xsa4jIbNzk/Xk3iKtdUN8dQjV3OrQRM= Date: Mon, 14 Jul 2025 11:34:14 +0300 From: Laurent Pinchart To: Ricardo Ribalda Cc: Mauro Carvalho Chehab , Guennadi Liakhovetski , Greg Kroah-Hartman , Hans de Goede , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org Subject: Re: [PATCH v8 5/5] media: uvcvideo: Auto-set UVC_QUIRK_MSXU_META Message-ID: <20250714083414.GA8243@pendragon.ideasonboard.com> References: <20250707-uvc-meta-v8-0-ed17f8b1218b@chromium.org> <20250707-uvc-meta-v8-5-ed17f8b1218b@chromium.org> <20250711195815.GH27674@pendragon.ideasonboard.com> <20250714080608.GB10401@pendragon.ideasonboard.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Mon, Jul 14, 2025 at 10:21:20AM +0200, Ricardo Ribalda wrote: > On Mon, 14 Jul 2025 at 10:06, Laurent Pinchart wrote: > > On Mon, Jul 14, 2025 at 09:46:45AM +0200, Ricardo Ribalda wrote: > > > On Fri, 11 Jul 2025 at 21:58, Laurent Pinchart wrote: > > > > On Mon, Jul 07, 2025 at 06:34:05PM +0000, Ricardo Ribalda wrote: > > > > > If the camera supports the MSXU_CONTROL_METADATA control, auto set the > > > > > MSXU_META quirk. > > > > > > > > > > Reviewed-by: Hans de Goede > > > > > Signed-off-by: Ricardo Ribalda > > > > > --- > > > > > drivers/media/usb/uvc/uvc_driver.c | 7 +++- > > > > > drivers/media/usb/uvc/uvc_metadata.c | 75 +++++++++++++++++++++++++++++++++++- > > > > > drivers/media/usb/uvc/uvcvideo.h | 2 +- > > > > > include/linux/usb/uvc.h | 3 ++ > > > > > 4 files changed, 84 insertions(+), 3 deletions(-) > > > > > > > > > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c > > > > > index 56ea20eeb7b9d5d92f3d837c15bdf11d536e9f2d..9de5abb43e19d9e876cddc5d7124592953db89ac 100644 > > > > > --- a/drivers/media/usb/uvc/uvc_driver.c > > > > > +++ b/drivers/media/usb/uvc/uvc_driver.c > > > > > @@ -2315,7 +2315,12 @@ static int uvc_probe(struct usb_interface *intf, > > > > > goto error; > > > > > } > > > > > > > > > > - uvc_meta_init(dev); > > > > > + ret = uvc_meta_init(dev); > > > > > + if (ret < 0) { > > > > > + dev_err(&dev->udev->dev, > > > > > + "Error initializing the metadata formats (%d)\n", ret); > > > > > + goto error; > > > > > + } > > > > > > > > > > if (dev->quirks & UVC_QUIRK_NO_RESET_RESUME) > > > > > udev->quirks &= ~USB_QUIRK_RESET_RESUME; > > > > > diff --git a/drivers/media/usb/uvc/uvc_metadata.c b/drivers/media/usb/uvc/uvc_metadata.c > > > > > index 77e03273d3cf6b00cac6ebb9b29b941f1cbfd9f7..59bb133baf9a73ef6a30fa8ead85aa90653d60f4 100644 > > > > > --- a/drivers/media/usb/uvc/uvc_metadata.c > > > > > +++ b/drivers/media/usb/uvc/uvc_metadata.c > > > > > @@ -10,6 +10,7 @@ > > > > > #include > > > > > #include > > > > > #include > > > > > +#include > > > > > #include > > > > > > > > > > #include > > > > > @@ -166,6 +167,71 @@ static const struct v4l2_file_operations uvc_meta_fops = { > > > > > .mmap = vb2_fop_mmap, > > > > > }; > > > > > > > > > > +static struct uvc_entity *uvc_meta_find_msxu(struct uvc_device *dev) > > > > > +{ > > > > > + static const u8 uvc_msxu_guid[16] = UVC_GUID_MSXU_1_5; > > > > > + 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 > > > > > > > > I'm confused here. If those are three different behaviours, then value > > > > != 1 would be value == 0 (as the third behaviour is value > 1). You test > > > > for !*data below, so 0 is not accepted as a valid value for this > > > > purpose. What am I missing ? > > > > > > There is a typo in the comment. > > > > > > Some devices require 1, some devices any value !=0, and other value=MAX. > > > I will fix it in a follow-up patch. > > > > The documentation of the control states that MSXU_CONTROL_METADATA > > reports the maximum size of the MS metadata generated by the device in > > kB, and the control should be set to the value reported by GET_MAX to > > enable metadata generation. That's what you're doing in this patch, so > > you can update the comment to document there. > > Some vendors assumed the kB was a typo in MS spec and used bytes instead :) > In this favor I must say that kB here sounds like a mistake, I haven't > seen more than 300 bytes of metadata. It doesn't seem to be a typo, as the documentation states The camera can produce metadata and the total size of such metadata can't exceed the dwValue - as reported by GET_MAX request – times 1024 bytes less the size of a UsbVideoHeader metadata payload, for any frame. It looks like a design mistake though. > Will send a patch with the updated documentation. > > > Some devices also don't support SET_CUR, in which case they should > > report GET_MIN == GET_DEF == GET_MAX. I assume GET_CUR should then also > > report the same value. Please also update the previous comment to > > explain this, the GET_CUR value check above is more about handling > > devices that always produce metadata than devices for which a driver has > > enabled metadata production. > > > > This leads to another question: should we enable metadata generation > > only when the metadata capture device is streaming ? > > This will lead to a lot of issues with very little benefit. > > We have no control over the order that the user will enable streamon > in the metadata and "normal" video devices. And the device will not > like that MSXU_CONTROL_METADATA changes during streamon. > > I have not seen any performance penalty by the 300 new bytes > transferred when the metadata is on. > > > > > > + * 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; > > > > > @@ -185,9 +251,14 @@ int uvc_meta_register(struct uvc_streaming *stream) > > > > > &uvc_meta_fops, &uvc_meta_ioctl_ops); > > > > > } > > > > > > > > > > -void uvc_meta_init(struct uvc_device *dev) > > > > > +int uvc_meta_init(struct uvc_device *dev) > > > > > { > > > > > unsigned int i = 0; > > > > > + int ret; > > > > > + > > > > > + ret = uvc_meta_detect_msxu(dev); > > > > > + if (ret) > > > > > + return ret; > > > > > > > > > > dev->meta_formats[i++] = V4L2_META_FMT_UVC; > > > > > > > > > > @@ -201,4 +272,6 @@ void uvc_meta_init(struct uvc_device *dev) > > > > > > > > > > /* IMPORTANT: for new meta-formats update UVC_MAX_META_DATA_FORMATS. */ > > > > > dev->meta_formats[i++] = 0; > > > > > + > > > > > + return 0; > > > > > } > > > > > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h > > > > > index 616adc417c62a58686beccbc440a5dfac0a2d588..a4c064c5e046f2a4adba742c8777a10619569606 100644 > > > > > --- a/drivers/media/usb/uvc/uvcvideo.h > > > > > +++ b/drivers/media/usb/uvc/uvcvideo.h > > > > > @@ -757,7 +757,7 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit, > > > > > void uvc_video_clock_update(struct uvc_streaming *stream, > > > > > struct vb2_v4l2_buffer *vbuf, > > > > > struct uvc_buffer *buf); > > > > > -void uvc_meta_init(struct uvc_device *dev); > > > > > +int uvc_meta_init(struct uvc_device *dev); > > > > > int uvc_meta_register(struct uvc_streaming *stream); > > > > > > > > > > int uvc_register_video_device(struct uvc_device *dev, > > > > > 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, \ > > > > > -- Regards, Laurent Pinchart