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Date: Fri, 15 Dec 2023 12:24:38 +0200
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Changhuang Liang <changhuang.liang@starfivetech.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Hans Verkuil <hverkuil-cisco@xs4all.nl>,
	Marvin Lin <milkfafa@gmail.com>,
	Bryan O'Donoghue <bryan.odonoghue@linaro.org>,
	Ming Qian <ming.qian@nxp.com>,
	Nicolas Dufresne <nicolas.dufresne@collabora.com>,
	Benjamin Gaignard <benjamin.gaignard@collabora.com>,
	Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>,
	Mingjia Zhang <mingjia.zhang@mediatek.com>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Sakari Ailus <sakari.ailus@linux.intel.com>,
	Dan Carpenter <dan.carpenter@linaro.org>,
	Jack Zhu <jack.zhu@starfivetech.com>, linux-media@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-staging@lists.linux.dev
Subject: Re: [PATCH v1 1/9] media: v4l2-ctrls: Add user controls for StarFive
 JH7110 ISP
Message-ID: <20231215102438.GH21146@pendragon.ideasonboard.com>
References: <20231214065027.28564-1-changhuang.liang@starfivetech.com>
 <20231214065027.28564-2-changhuang.liang@starfivetech.com>
 <20231214113955.GK12450@pendragon.ideasonboard.com>
 <e6059181-a1bb-438b-8490-108c64316171@starfivetech.com>
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In-Reply-To: <e6059181-a1bb-438b-8490-108c64316171@starfivetech.com>

Hi Changhuang,

On Fri, Dec 15, 2023 at 01:55:09PM +0800, Changhuang Liang wrote:
> On 2023/12/14 19:39, Laurent Pinchart wrote:
> > On Wed, Dec 13, 2023 at 10:50:19PM -0800, Changhuang Liang wrote:
> >> Add a control base for StarFive JH7110 ISP driver controls, and reserve
> >> 32 controls，also add some controls for StarFive JH7110 ISP.
> > 
> > ISP parameters should be passed through parameters buffers, not V4L2
> > control. See for instance the V4L2_META_FMT_RK_ISP1_PARAMS format in the
> > mainline kernel, it describes how to store ISP parameters in a buffer.
> > The rkisp1 driver is an example of how this can be implemented.
> 
> That means I need to add a video output device before ISP subdev? And 
> use queue/dequeue buffer to get the ISP paremeters?

Yes, that is correct.

> > Please note that the ISP parameters need to be documented precisely,
> > regardless of how they're passed by userspace to the kernel. Even with
> > V4L2 controls, documentation would be needed. Please see below for
> > additional comments.
> 
> I will add annotations for this file next version.
> 
> >> Signed-off-by: Changhuang Liang <changhuang.liang@starfivetech.com>
> >> ---
> >>  MAINTAINERS                        |   1 +
> >>  include/uapi/linux/jh7110-isp.h    | 342 +++++++++++++++++++++++++++++
> >>  include/uapi/linux/v4l2-controls.h |   6 +
> [...]

-- 
Regards,

Laurent Pinchart