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Mon, 27 May 2024 09:44:26 +0300 (EEST) Date: Mon, 27 May 2024 06:44:25 +0000 From: Sakari Ailus To: Laurent Pinchart Cc: Jacopo Mondi , Linux Media Mailing List , David Plowman , Naushir Patuck , Nick Hollinghurst , Dave Stevenson , Tomi Valkeinen , Kieran Bingham , Hans Verkuil , Mauro Carvalho Chehab Subject: Re: [PATCH v7 7/8] media: raspberrypi: Add support for PiSP BE Message-ID: References: <20240524140024.161313-1-jacopo.mondi@ideasonboard.com> <20240524140024.161313-8-jacopo.mondi@ideasonboard.com> <20240527011911.GD24374@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: <20240527011911.GD24374@pendragon.ideasonboard.com> Hi Laurent, On Mon, May 27, 2024 at 04:19:11AM +0300, Laurent Pinchart wrote: > > One API-based solution could be moving the IOCTL interface to MC device > > node only. This wouldn't be a small change so I'm not proposing doing that > > now. > > I think we could also use the request API. It is a bit more cumbersome > to use from a userspace point of view, but this driver is meant to be > used from libcamera, so we can isolate applications from the extra > burden. > > We will need to add support for formats in the request API (or rather > for requests in the format ioctls). > > From a kernel point of view, the helpers used by the codec drivers may > not be suitable for ISP drivers, but I don't think it would be very > difficult to implement other helpers is needed, isolating the ISP driver > from the complexity of the request API. > > This doesn't preclude developing a better userspace API with ioctls on > the MC device node only at a later point. If the above-mentioned kernel > helpers are done right, transitioning to a new userspace API will have > minimal impact on drivers. This is indeed the third feasible option. I agree. The work on the framework side might not be that much either. -- Regards, Sakari Ailus