Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750915AbVKERjl (ORCPT ); Sat, 5 Nov 2005 12:39:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750925AbVKERjl (ORCPT ); Sat, 5 Nov 2005 12:39:41 -0500 Received: from van-1-67.lab.dnainternet.fi ([62.78.96.67]:42690 "EHLO mail.zmailer.org") by vger.kernel.org with ESMTP id S1750906AbVKERjk (ORCPT ); Sat, 5 Nov 2005 12:39:40 -0500 Date: Sat, 5 Nov 2005 19:39:39 +0200 From: Matti Aarnio To: Jean Delvare Cc: LKML Subject: Re: I2C regression in post 2.6.14 gits.. -- get_user_pages() is real bug.. Message-ID: <20051105173939.GF3423@mea-ext.zmailer.org> References: <20051102223818.GE3423@mea-ext.zmailer.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1627 Lines: 49 On Fri, Nov 04, 2005 at 10:29:34AM +0100, Jean Delvare wrote: > Hi Matti, > > On 2005-11-04, Matti Aarnio wrote: > > Specifically, BTTV driver fails to control internal > > I2C devices in Hauppauge WinTV card with Bt848 onboard. > > Can you detail how you came up with this diagnosis? > > > Baseline 2.6.14 works fine, but 2.6.14-git2 fails. > > Can you please try 2.6.14-git1 and 2.6.14-rc5-mm1? This should help us > norrow the faulty patch. Also, please confirm that 2.6.14-git7 still has > the problem. > > > Any ideas ? Possible fixes ? > > Enable as many debugging as possible, in particular I2C Core debugging > (I2C_DEBUG_CORE=y) in a working kernel and a non-working kernel, and > send both logs for comparison. > > Thanks a lot for testing, BTW. Since then I have been tracking of what really fails in the bttv driver, and running: strace -o tvtime.log tvtime Result is most revealing in failures. The fault is not in I2C, but appears in video_buf module failing calls of get_user_pages() with -EFAULT. There has been lots of discussion about it back in August, but apparently only now in post 2.6.14 the changes made it into mm/memory.c which faulted this thing for BTTV. Oh yes, I do use Fedora Core development kernels, and don't usually (anymore) compile things myself, but now I had a weekend off... > -- > Jean Delvare /Matti Aarnio - 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/