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X-CSE-ConnectionGUID: a5fDykwgRiWZeU8dyN8IjQ== X-CSE-MsgGUID: ux2eoKmCRveHzpcKPlIWrw== X-IronPort-AV: E=McAfee;i="6800,10657,11557"; a="72056704" X-IronPort-AV: E=Sophos;i="6.18,277,1751266800"; d="scan'208";a="72056704" Received: from orviesa002.jf.intel.com ([10.64.159.142]) by orvoesa104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Sep 2025 04:46:18 -0700 X-CSE-ConnectionGUID: Kkmx7c2ZSI6cehvMauGNDw== X-CSE-MsgGUID: Jaqt5mWoS0enG8lT79Ca7Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.18,277,1751266800"; d="scan'208";a="206574622" Received: from ettammin-mobl2.ger.corp.intel.com (HELO kekkonen.fi.intel.com) ([10.245.245.108]) by orviesa002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Sep 2025 04:46:11 -0700 Received: from kekkonen.localdomain (localhost [IPv6:::1]) by kekkonen.fi.intel.com (Postfix) with SMTP id CD25D11F982; Fri, 19 Sep 2025 14:46:08 +0300 (EEST) Date: Fri, 19 Sep 2025 14:46:08 +0300 Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo From: Sakari Ailus To: Laurent Pinchart Cc: Jacopo Mondi , linux-media@vger.kernel.org, hans@jjverkuil.nl, Prabhakar , Kate Hsuan , Alexander Shiyan , Dave Stevenson , Tommaso Merciai , Umang Jain , Benjamin Mugnier , Sylvain Petinot , Christophe JAILLET , Julien Massot , Naushir Patuck , "Yan, Dongcheng" , "Cao, Bingbu" , "Qiu, Tian Shu" , "Wang, Hongju" , Stefan Klug , Mirela Rabulea , =?iso-8859-1?Q?Andr=E9?= Apitzsch , Heimir Thor Sverrisson , Kieran Bingham , Stanislaw Gruszka , Mehdi Djait , Ricardo Ribalda Delgado , Hans de Goede , Tomi Valkeinen Subject: Re: [PATCH v11 26/66] media: Documentation: Document embedded data guidelines for camera sensors Message-ID: References: <20250825095107.1332313-1-sakari.ailus@linux.intel.com> <20250825095107.1332313-27-sakari.ailus@linux.intel.com> <20250903204059.GW3648@pendragon.ideasonboard.com> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250903204059.GW3648@pendragon.ideasonboard.com> Hi Laurent, On Wed, Sep 03, 2025 at 10:40:59PM +0200, Laurent Pinchart wrote: > On Wed, Sep 03, 2025 at 04:37:12PM +0300, Sakari Ailus wrote: > > On Mon, Sep 01, 2025 at 06:42:33PM +0200, Jacopo Mondi wrote: > > > On Mon, Aug 25, 2025 at 12:50:27PM +0300, Sakari Ailus wrote: > > > > Document how embedded data support should be implemented for camera > > > > sensors, and when and how CCS embedded data layout should be referenced. > > > > > > > > Signed-off-by: Sakari Ailus > > > > Reviewed-by: Julien Massot > > > > --- > > > > .../media/drivers/camera-sensor.rst | 20 +++++++++++++++++++ > > > > 1 file changed, 20 insertions(+) > > > > > > > > diff --git a/Documentation/userspace-api/media/drivers/camera-sensor.rst b/Documentation/userspace-api/media/drivers/camera-sensor.rst > > > > index a8e0e4accbc9..a719c6f88f11 100644 > > > > --- a/Documentation/userspace-api/media/drivers/camera-sensor.rst > > > > +++ b/Documentation/userspace-api/media/drivers/camera-sensor.rst > > > > @@ -117,3 +117,23 @@ register programming sequences shall initialize the :ref:`V4L2_CID_HFLIP > > > > values programmed by the register sequences. The default values of these > > > > controls shall be 0 (disabled). Especially these controls shall not be inverted, > > > > independently of the sensor's mounting rotation. > > > > + > > > > +Embedded data > > > > +------------- > > > > + > > > > +Many sensors, mostly raw sensors, support embedded data which is used to convey > > > > +the sensor configuration for the captured frame back to the host. While CSI-2 is > > > > +the most common data interface used by such sensors, embedded data can be > > > > +available on other interfaces as well. > > > > + > > > > +Embedded data support is indicated by the presence of an internal sink pad (pad > > > > +that has both the ``MEDIA_PAD_FL_SINK `` and > > > > +``MEDIA_PAD_FL_INTERNAL `` flags set) with a metadata > > > > > > These are rendered as verbatim text, not links > > > > Will fix for v12. > > > > > > +format to model the embedded data stream. If the sub-device driver supports > > > > +disabling embedded data, this can be done by disabling the embedded data route > > > > +via the ``VIDIOC_SUBDEV_S_ROUTING`` IOCTL. > > > > + > > > > +In general, changing the embedded data layout from the driver-configured values > > > > +is not supported. The height of the metadata is device-specific and the width > > > > +is that (or less of that) of the image width, as configured on the pixel data > > > > > > s/is that (or less of that) of/is the same (or smaller) than/ > > > > > > reads better in my possibily broke English > > > > How about: > > > > The height of the metadata is device-specific and equal to or less than the > > image width, as configured on the pixel data stream. > > That doesn't sound right. "The *height* is [...] than the image > *width*". I'll give it a try: > > ---- > In general, changing the embedded data layout from the driver-configured > values is not supported. The height of the metadata is typically a small > fixed device-specific value, and the width is equal to the image width, > as configured on the pixel data. > ---- > > That drops the "or less" though. When is the embedded data width smaller > than the image data width, and is it configurable in that case, or does > it have a fixed value that depends on the image data width ? The text is fine but I think we should add "or less". E.g. the ov2740 embedded data lines are shorter than the image and that is also common elsewhere, too. I used this: In general, changing the embedded data layout from the driver-configured values is not supported. The height of the metadata is device-specific and equal to or less than the image width, as configured on the pixel data stream. -- Regards, Sakari Ailus