From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751812AbYLWMp0 (ORCPT ); Tue, 23 Dec 2008 07:45:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751021AbYLWMpO (ORCPT ); Tue, 23 Dec 2008 07:45:14 -0500 Received: from mail.gmx.net ([213.165.64.20]:53269 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750955AbYLWMpM (ORCPT ); Tue, 23 Dec 2008 07:45:12 -0500 X-Authenticated: #20450766 X-Provags-ID: V01U2FsdGVkX1+5Yi4Wrc258ly+4qDQJwz0AQMPzTGl0t1n6vD6T/ cqihQCk0QwROoO Date: Tue, 23 Dec 2008 13:45:14 +0100 (CET) From: Guennadi Liakhovetski To: Robert Schwebel cc: 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 In-Reply-To: <20081223121300.GL9472@pengutronix.de> Message-ID: 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 X-Y-GMX-Trusted: 0 X-FuHaFi: 0.51 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer