From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964863AbWFSWcX (ORCPT ); Mon, 19 Jun 2006 18:32:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964960AbWFSWcX (ORCPT ); Mon, 19 Jun 2006 18:32:23 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.31.123]:40923 "EHLO atrey.karlin.mff.cuni.cz") by vger.kernel.org with ESMTP id S964955AbWFSWcW (ORCPT ); Mon, 19 Jun 2006 18:32:22 -0400 Date: Mon, 19 Jun 2006 23:57:18 +0200 From: Pavel Machek To: Salvatore Sanfilippo Cc: linux-kernel@vger.kernel.org Subject: Re: v4l device in userspace Message-ID: <20060619215718.GA1648@openzaurus.ucw.cz> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.3.27i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > I've a little program running in the phone, capturing > images from the camera and sending it to the > linux box via bluetooth. Nice! > Basically I've to pass by the kernel just for > the interface, and not to do real kernel-side work > (like to access to the some kind of hardware). > > So I've some questions ( thanks in advance > for any reply). > > 1) What's the best way to pass relatively > high-band data between the v4l fake driver > and userspace? A char device will do the > work? ioctl? > > 2) What about some way to handle ioctl > directly from userspace? Given this support > I may implement the whole code in userspace. > And I guess there are a lot of other real world > problems that can be handled in userspace > given the ability to handle ioctl from there. > > If you think 2) is reasonable I may actually > implement some simple form of generic > char driver that just allows userspace > programs to handle read/write/ioctl > opreations, and then use this to fix > my real issue. You probably want to do something v4l specigic... but generic userspace driver able to do read/write/ioctl would be very nice. Lots of devices these days are on usb, and that can be done from userspace, for example. Pavel -- 64 bytes from 195.113.31.123: icmp_seq=28 ttl=51 time=448769.1 ms