Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751983AbYLWM4X (ORCPT ); Tue, 23 Dec 2008 07:56:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751078AbYLWM4P (ORCPT ); Tue, 23 Dec 2008 07:56:15 -0500 Received: from metis.ext.pengutronix.de ([92.198.50.35]:35502 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751055AbYLWM4O (ORCPT ); Tue, 23 Dec 2008 07:56:14 -0500 Date: Tue, 23 Dec 2008 13:56:12 +0100 From: Sascha Hauer To: Guennadi Liakhovetski Cc: Robert Schwebel , linux-kernel@vger.kernel.org, linux-fbdev-devel@lists.sourceforge.net, adaplas@gmail.com, linux-arm-kernel@lists.arm.linux.org.uk, Dan Williams Subject: Re: [PATCH 2/4 v4] i.MX31: Image Processing Unit DMA and IRQ drivers Message-ID: <20081223125612.GB17159@pengutronix.de> Mail-Followup-To: Guennadi Liakhovetski , Robert Schwebel , linux-kernel@vger.kernel.org, linux-fbdev-devel@lists.sourceforge.net, adaplas@gmail.com, linux-arm-kernel@lists.arm.linux.org.uk, Dan Williams References: <20081218225834.GJ20756@pengutronix.de> <20081222183753.GD1614@pengutronix.de> <20081223105006.GE1614@pengutronix.de> <20081223121300.GL9472@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Sent-From: Pengutronix Entwicklungszentrum Nord - Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Impressum: Pengutronix - Linux Solutions for Science and Industry Handelsregister: Amtsgericht Hildesheim, HRA 2686 Peiner Strasse 6-8, 31137 Hildesheim, Germany Phone: +49-5121-206917-0 | Fax: +49-5121-206917-5555 Inhaber: Dipl.-Ing. Robert Schwebel X-Message-Flag: See Message Headers for Impressum X-Uptime: 13:50:51 up 9 days, 17:18, 10 users, load average: 0.00, 0.00, 0.00 User-Agent: Mutt/1.5.18 (2008-05-17) X-SA-Exim-Connect-IP: 2001:6f8:1178:2:215:17ff:fe12:23b0 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3920 Lines: 81 On Tue, Dec 23, 2008 at 01:45:14PM +0100, Guennadi Liakhovetski wrote: > Hi Robert, > > On Tue, 23 Dec 2008, Robert Schwebel wrote: > > > On Tue, Dec 23, 2008 at 11:50:06AM +0100, Sascha Hauer wrote: > > > > You mean an output v4l device? I think overlays are handled by framebuffer > > > > drivers... But I'm also not quite sure about it, however, handling overlay > > > > as another framebuffer seems logical to me. > > > > > > Well the DMA engine seems to suggest that frames should be passed around > > > whereas the framebuffer API only has a single frame. That would fit > > > better into the v4l API. Also the IPU can do things like colourspace > > > conversion and hw scaling which would fit into the V4L API. > > > > Looks like a candidate for gstreamer on the userspace end. Can it be > > decoupled enough to make proper plugins out of it? > > I think, the question is rather "can a driver be written for IPU to > support some sane hardware-neutral image data manipulation API, like v4l?" > Then you can start writing any user-space apps on top of that API. So, as > long as there is such an API, I think, we can put it on IPU, yes. My > problems ATM is - no use-case. What concerns overlay, it is not used in > the current application, as for image format conversion from the camera - > I only have a Bayer camera to test with. I even cannot test monochrome > sanely, because of a lack of a cable:-) And Bayer and monochrome don't > make good candidates for such conversions - they are not supported by the > IPU. > > > > BTW is the overlay framebuffer useful in it's current implementation? > > > There seems to be no way to adjust the x/y offset or the blending > > > modes. > > > > The API Eric Miao just posted for the PXA looks sane to me. > > I'll have a look, but as I said: -ENOUSER:-) > > > > > If there are no other problems with v5, could we maybe take it as a > > > > basis and then I would submit a patch to reduce the number of IRQs? > > > > > > Please understand my concerns with this driver. It's a quite complex > > > beast and experience shows that once a driver is in the kernel it is > > > far more complicated to change it than to do it right the first way. > > > > Especially when it comes to userspace visible things. > > > > > You know that I'm also interested in having a MX31 framebuffer (and > > > camera) driver in kernel but I want to make sure that it works > > > properly and leaves room for feature enhancements without having to > > > refactor the whole driver. > > > > Yup, looks like it would be better to cook it another round instead of > > trying to bring in a half-tested driver with brute-force. > > Ok, no problem. Let's just decide > > 1. is the drivers/dma the final location. > 2. do dmaengine maintainers accept it in present form or require any > amendments. > 3. which interrupts we make visible by default for irq_desc[] and what > granularity we want to enable the rest (we could even just make > CONFIG_ALL_IPU_IRQS and be 95% sure noone will ever need them.) > 4. throw away every trace of overlay support - if anyone ever needs it > they should be able to dig it out in ML archives. Or from the Freescale BSP. This sounds good to me. It would also enable someone to write a v4l2 based overlay driver without interfering with the existing framebuffer driver. 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 | -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/