From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Schwebel Subject: Re: [PATCH 2/4 v4] i.MX31: Image Processing Unit DMA and IRQ drivers Date: Tue, 23 Dec 2008 13:13:00 +0100 Message-ID: <20081223121300.GL9472@pengutronix.de> References: <20081218225834.GJ20756@pengutronix.de> <20081222183753.GD1614@pengutronix.de> <20081223105006.GE1614@pengutronix.de> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <20081223105006.GE1614@pengutronix.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: 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 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? > 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. > > 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. rsc -- 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 |