From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail1.matrix-vision.com ([78.47.19.71]:51481 "EHLO mail1.matrix-vision.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752574Ab3FLQUR (ORCPT ); Wed, 12 Jun 2013 12:20:17 -0400 Message-ID: <51B89EDA.90107@matrix-vision.de> Date: Wed, 12 Jun 2013 18:16:26 +0200 From: Michael Jones MIME-Version: 1.0 To: Laurent Pinchart CC: linux-media ML Subject: double-buffering with the omap3 parallel interface Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Hi Laurent & co., I'd like to look at what the maximum possible frame rates are for a sensor connected to the OMAP3 ISP CCDC via the parallel interface, writing frames directly to memory. I understand that there is some minimum amount of time required between frames to pass on the finished frame and set up the address to be written to for the next frame. From the manual it looks like a double buffering scheme would've been available on a different sensor interface, but isn't on the parallel one. Do I see that right? Is it impossible to use double buffering of any sort while using the parallel interface to memory? I'm still using an older version of the driver, but I've browsed the current state of the code, too. What behavior do you expect if the time between frames is too short for the buffer management? Can it be recovered from? Has this behavior changed in recent versions? I see from the ISP block diagram that the "circular buffer" is between the SBL and the MMU. Could this maybe be used to help the situation? It seems to currently not be used at all along this path. thanks, Michael MATRIX VISION GmbH, Talstrasse 16, DE-71570 Oppenweiler Registergericht: Amtsgericht Stuttgart, HRB 271090 Geschaeftsfuehrer: Gerhard Thullner, Werner Armingeon, Uwe Furtner, Erhard Meier