From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]:40722 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752517Ab1IZUDt (ORCPT ); Mon, 26 Sep 2011 16:03:49 -0400 Message-ID: <4E80DA9B.5000604@redhat.com> Date: Mon, 26 Sep 2011 17:03:39 -0300 From: Mauro Carvalho Chehab MIME-Version: 1.0 To: Thomas Petazzoni CC: Laurent Pinchart , Devin Heitmueller , linux-media@vger.kernel.org, srinivasa.deevi@conexant.com, Maxime Ripard Subject: Re: cx231xx: DMA problem on ARM References: <20110921135604.64363a2e@skate> <20110926101323.41708d64@skate> <4E80B73F.5020804@redhat.com> <201109262102.49056.laurent.pinchart@ideasonboard.com> <20110926215954.5ab059e4@skate> In-Reply-To: <20110926215954.5ab059e4@skate> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-media-owner@vger.kernel.org List-ID: Em 26-09-2011 16:59, Thomas Petazzoni escreveu: > Hello Laurent, > > Le Mon, 26 Sep 2011 21:02:48 +0200, > Laurent Pinchart a écrit : > >> Are you using the MMAP or USERPTR capture method ? If using MMAP, can >> you try (as a test only) to unmap the buffer before queueing it and >> to remap it after dequeuing it ? > > So far, we have used VLC, Cheese, or a simple OpenCV based application > to test the V4L2 device on our ARM platform, and I have no idea which > capture method those are using. Is there a very simple V4L test > application that we could use to hack the buffer unmap/remap trick > you're suggesting as a test ? The simplest application is the v4l2grab util: http://git.linuxtv.org/v4l-utils.git/blob/HEAD:/contrib/test/v4l2grab.c it uses libv4l to convert to RGB and outputs a series of ppm images. By generating one image per frame, it is easy to check artifacts on each image. > > Regards, > > Thomas