From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sascha Hauer Subject: Re: [PATCH 2/4 v4] i.MX31: Image Processing Unit DMA and IRQ drivers Date: Tue, 23 Dec 2008 13:08:15 +0100 Message-ID: <20081223120815.GA17159@pengutronix.de> References: <20081218225834.GJ20756@pengutronix.de> <20081222183753.GD1614@pengutronix.de> <20081222200337.GD9472@pengutronix.de> <4950B8C6.30309@gmail.com> <20081223105246.GF1614@pengutronix.de> <4950CC38.3090200@gmail.com> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <4950CC38.3090200@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Dmitry Krivoschekov Cc: Robert Schwebel , Guennadi Liakhovetski , linux-kernel@vger.kernel.org, linux-fbdev-devel@lists.sourceforge.net, adaplas@gmail.com, linux-arm-kernel@lists.arm.linux.org.uk, Dan Williams On Tue, Dec 23, 2008 at 02:32:08PM +0300, Dmitry Krivoschekov wrote: > Sascha Hauer wrote: > > On Tue, Dec 23, 2008 at 01:09:10PM +0300, Dmitry Krivoschekov wrote: > >> Robert Schwebel wrote: > >>> On Mon, Dec 22, 2008 at 07:37:53PM +0100, Sascha Hauer wrote: > >>>> Another thing is the overlay framebuffer. I think it's mainly useful > >>>> to display video streams. > >>> Right. The idea is that you can push a video stream into /dev/fb1 (for > >>> example by using the gstreamer fbdev sink) while displaying widgets from > >>> a GUI toolkit on /dev/fb0. > >>> > >>>> Maybe it's better to implement this as a v4l device as unlike the > >>>> framebuffer API the v4l API is designed to handle different image > >>>> buffers. > >>> Huh? v4l is image-frames-to-userspace, not vice versa. > >>> > >> ...and vice versa too, v4l2 is not about input devices only but it is > >> also related to output devices, v4l2 spec even has a special chapter > >> dedicated to overlays [1]. Moreover, you can find such a driver within > >> Freescale's BSP [2]. Another example is Omap's videoout driver [3]. > > > > Are you aware of any application making use of this feature? > > IIRC, mplayer is able to output on a v4l2 device. Yes, but only on some MPEG decoder cards. Raw frames are not supported. > Also, Freescale's > i.MX31 ADS BSP contained a bunch of V4L2 unit tests, including v4l2 output. Ah ok, didn't know that Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |