From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from galahad.ideasonboard.com ([185.26.127.97]:45245 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751827AbcLHNjc (ORCPT ); Thu, 8 Dec 2016 08:39:32 -0500 From: Laurent Pinchart To: Guennadi Liakhovetski Cc: Linux Media Mailing List , Hans Verkuil Subject: Re: [PATCH v2 3/3] uvcvideo: add a metadata device node Date: Thu, 08 Dec 2016 15:39:57 +0200 Message-ID: <15282460.lOulU7IMKd@avalon> In-Reply-To: References: <6827808.RfcVLAN17o@avalon> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-media-owner@vger.kernel.org List-ID: Hi Guennadi, On Thursday 08 Dec 2016 14:34:46 Guennadi Liakhovetski wrote: > On Tue, 6 Dec 2016, Laurent Pinchart wrote: > > On Tuesday 06 Dec 2016 11:39:22 Guennadi Liakhovetski wrote: > >> On Tue, 6 Dec 2016, Laurent Pinchart wrote: > >>> On Monday 05 Dec 2016 23:13:53 Guennadi Liakhovetski wrote: > >>>> On Tue, 6 Dec 2016, Laurent Pinchart wrote: > >>>>>>>> + /* > >>>>>>>> + * Register a metadata node. TODO: shall this only be enabled > >>>>>>>> for some > >>>>>>>> + * cameras? > >>>>>>>> + */ > >>>>>>>> + if (!(dev->quirks & UVC_QUIRK_BUILTIN_ISIGHT)) > >>>>>>>> + uvc_meta_register(stream); > >>>>>>>> + > >>>>>>> > >>>>>>> I think so, only for the cameras that can produce metadata. > >>>>>> > >>>>>> Every UVC camera produces metadata, but most cameras only have > >>>>>> standard fields there. Whether we should stream standard header > >>>>>> fields from the metadata node will be discussed later. If we do > >>>>>> decide to stream standard header fields, then every USB camera gets > >>>>>> metadata nodes. If we decide not to include standard fields, how do > >>>>>> we know whether the camera has any private fields in headers > >>>>>> without streaming from it? Do you want a quirk for such cameras? > >>>>> > >>>>> Unless they can be detected in a standard way that's probably the > >>>>> best solution. > > How about a module parameter with a list of VID:PID pairs? I'd like something that works out of the box for end-users, at least in most cases. There's already a way to set quirks through a module parameter, and I think I'd accept a patch extending that it make it VID:PID dependent. That's an acceptable solution for testing, but should not be considered as the way to go for production. > The problem with the quirk is, that as vendors produce multiple cameras with > different PIDs they will have to push patches for each such camera. How many such devices do you expect ? -- Regards, Laurent Pinchart