From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from moutng.kundenserver.de ([212.227.126.171]:58875 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755315Ab1HDTC1 (ORCPT ); Thu, 4 Aug 2011 15:02:27 -0400 Date: Thu, 4 Aug 2011 21:02:19 +0200 (CEST) From: Guennadi Liakhovetski To: Jean-Francois Moine cc: Linux Media Mailing List , Mauro Carvalho Chehab , Hans de Goede , Theodore Kilgore , workshop-2011@linuxtv.org Subject: Re: [Workshop-2011] Media Subsystem Workshop 2011 In-Reply-To: <20110804184020.6edb96d8@tele> Message-ID: References: <4E398381.4080505@redhat.com> <4E39B150.40108@redhat.com> <4E3A84F0.5050208@redhat.com> <4E3A9332.1060404@redhat.com> <20110804184020.6edb96d8@tele> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-media-owner@vger.kernel.org List-ID: (re-adding all from the original CC-list, please, don't drop anyone) On Thu, 4 Aug 2011, Jean-Francois Moine wrote: > On Thu, 04 Aug 2011 09:40:18 -0300 > Mauro Carvalho Chehab wrote: > > > > What we need for this is a simple API (new v4l ioctl's I guess) for the > > > stillcam mode of these dual mode cameras (stillcam + webcam). So that the > > > webcam drivers can grow code to also allow access to the stored pictures, > > > which were taken in standalone (iow not connected to usb) stillcam mode. > > > > > > This API does not need to be terribly complex. AFAIK all of the currently > > > supported dual cam cameras don't have filenames only picture numbers, > > > so the API could consist of a simple, get highest picture nr, is picture > > > X present (some slots may contain deleted pictures), get picture X, > > > delete picture X, delete all API. > > > > That sounds to work. I would map it on a way close to the controls API > > (or like the DVB FE_[GET|SET]_PROPERTY API), as this would make easier to expand > > it in the future, if we start to see webcams with file names or other things > > like that. > > I did not follow all the thread, but I was wondering about an other > solution: what about offering both USB mass storage and webcam accesses? > > When a dual-mode webcam is plugged in, the driver creates two devices, > the video device /dev/videox and the volume /dev/sdx. When the webcam is > opened, the volume cannot be mounted. When the volume is mounted, the > webcam cannot be opened. There is no need for a specific API. As Mauro > said: > > > For those, we may eventually need some sort of locking between > > the USB storage and V4L. > > That's all. By where am I wrong? That'd also be my understanding. There are already several standard ways to access data on still cameras: mass-storage, PTP, MTP, why invent Yet Another One? "Just" learn to share a device between several existing drivers. Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/