From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Thu, 17 Aug 2006 16:36:05 +0100 (BST) Received: from gprs189-60.eurotel.cz ([160.218.189.60]:53257 "EHLO spitz.ucw.cz") by ftp.linux-mips.org with ESMTP id S20037524AbWHQPgE (ORCPT ); Thu, 17 Aug 2006 16:36:04 +0100 Received: by spitz.ucw.cz (Postfix, from userid 0) id 48AA92787F; Thu, 17 Aug 2006 15:31:38 +0000 (UTC) Date: Thu, 17 Aug 2006 15:31:38 +0000 From: Pavel Machek To: Thomas Koeller Cc: =?iso-8859-1?Q?=C9ric?= Piel , linux-kernel@vger.kernel.org, alan@lxorguk.ukuu.org.uk, linux-mips@linux-mips.org, Thomas =?iso-8859-1?Q?K=F6ller?= Subject: Re: [PATCH] Image capturing driver for Basler eXcite smart camera Message-ID: <20060817153138.GE5950@ucw.cz> References: <200608102318.04512.thomas.koeller@baslerweb.com> <44E09C7E.204@lifl.fr> <200608142126.29171.thomas.koeller@baslerweb.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200608142126.29171.thomas.koeller@baslerweb.com> User-Agent: Mutt/1.5.9i Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 12353 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: pavel@suse.cz Precedence: bulk X-list: linux-mips Hi! > > If so then the Video4Linux2 API is still the best way to implement the > > protocol to pass data between the user-space programs and the driver. > > The V4L2 API doesn't says that the camera must be far away from the > > processor, it can work for USB webcams, for Firewire video camera, PCI > > TV tuners, and probably also for your device. Using the V4L2 not only > > has the advantage of being a well tested API for communicating video > > related information with the user-space but it also buys you the fact > > that any program available on Linux for video should be able to directly > > detect and use the captor! > > Sorry, but no. The camera has been designed to be used in industrial > control applications, such as quality assurance. Think of an automated > inspection of a certain product, where the inspection is integrated > into the production process. Faulty products are sorted out. For this to > work it is absolutely necessary to get the maximum speed (image frames > per second) out of the hardware, so image acquisition and processing > must be carried out in parallel. The way to achieve this is have the > driver manage a queue of image buffers to fill, so it will continue > grabbing images even if no read operation is currently pending. Also, > the ability to attach user-specific context information to every buffer > is essential. Well, I guess v4l api will need to be improved, then. That is still not a reason to introduce completely new api... -- Thanks for all the (sleeping) penguins.