From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E95F7C3A59B for ; Mon, 2 Sep 2019 08:53:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B8A0E215EA for ; Mon, 2 Sep 2019 08:53:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="pLvLkYux" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730803AbfIBIxN (ORCPT ); Mon, 2 Sep 2019 04:53:13 -0400 Received: from perceval.ideasonboard.com ([213.167.242.64]:58754 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729849AbfIBIxM (ORCPT ); Mon, 2 Sep 2019 04:53:12 -0400 Received: from pendragon.ideasonboard.com (231.125-247-81.adsl-dyn.isp.belgacom.be [81.247.125.231]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 95936303; Mon, 2 Sep 2019 10:53:10 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1567414390; bh=L7HfyK6AoCRBwfi7sSsavkmrIFgZvYJeM1TmWRV84A0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pLvLkYuxhClpk6qiiHyro9cQILbPHJyPNKdx/3LkmR5z74f9jXMr544uWI1jLqpeo R21dcz3QNHON2GB+ax6swl0OzoOlr2V1X6C1ZitVklecAbr+fwlADnCj83WqZxOpM1 cJBlbGOAftzet23JO7p57mWYjcauMFgth11NRtoQ= Date: Mon, 2 Sep 2019 11:53:03 +0300 From: Laurent Pinchart To: Pavel Machek Cc: Hans Verkuil , Jacopo Mondi , Mauro Carvalho Chehab , Sakari Ailus , "open list:MEDIA INPUT INFRASTRUCTURE (V4L/DVB)" , open list Subject: Re: [RFC 2/5] media: v4l2-ctrl: Document V4L2_CID_LOCATION Message-ID: <20190902085303.GG4777@pendragon.ideasonboard.com> References: <20190814224340.GD5015@pendragon.ideasonboard.com> <664fe7b3-9051-30da-736e-710a4e9cecde@xs4all.nl> <20190815143423.vaoswb4jvzd2blxp@uno.localdomain> <20190901172457.GC1047@bug> <20190902080002.GC4777@pendragon.ideasonboard.com> <20190902080657.GC15850@amd> <20190902081942.GE4777@pendragon.ideasonboard.com> <20190902082739.GE15850@amd> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190902082739.GE15850@amd> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Pawel, On Mon, Sep 02, 2019 at 10:27:39AM +0200, Pavel Machek wrote: > On Mon 2019-09-02 11:19:42, Laurent Pinchart wrote: > > On Mon, Sep 02, 2019 at 10:06:57AM +0200, Pavel Machek wrote: > >>>>> Single integer. It's read-only, so it just reports the location. > >>>>> > >>>>> It would be different if this was a writable control: then you need to > >>>>> know which locations are possible to set, and that requires a menu type. > >>>>> > >>>>> But it doesn't make sense to set the location from software. However, the > >>>>> location might change as a result of other changes: e.g. if the camera > >>>>> has motor control of the tilt and the tilt changes from forward facing to > >>>>> downward facing, then the driver might change the location from FRONT > >>>>> to DOWN. A convoluted example perhaps, but this is just brainstorming. > >>>> > >>>> There are phones with exactly such camera setup. And yes, it makes > >>>> sense to be writable in that case, as software can move the camera in > >>>> such case. > >>> > >>> Out of curiosity, what phones are those ? > >> > >> This one: > >> > >> https://www.samsung.com/global/galaxy/galaxy-a80/ > > > > Interesting device. I'm not sure we should control that through a > > location control though, as it seems there's more than the rotation of > > the camera involved. In any case I wouldn't care about it for now, and > > turn the location control from read-only to read-write later if needed. > > We need more information and more thought to support that use case. > > Well, the mechanism is there just to rotate the camera. But we don't know how it's implemented, it could be heavily firmware-based for instance. > Anyway, that phone is probably nowhere close to having mainline > support, so... If we need to support such a device in the future (and I hope we will :-)) then I'm totally fine expanding the features of the location control. My only concern is that I don't want to over-design it right now without having enough information about the hardware that would make use of it. -- Regards, Laurent Pinchart