Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261213AbUJYT22 (ORCPT ); Mon, 25 Oct 2004 15:28:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262011AbUJYP7n (ORCPT ); Mon, 25 Oct 2004 11:59:43 -0400 Received: from hirsch.in-berlin.de ([192.109.42.6]:53710 "EHLO hirsch.in-berlin.de") by vger.kernel.org with ESMTP id S261988AbUJYPlU (ORCPT ); Mon, 25 Oct 2004 11:41:20 -0400 X-Envelope-From: kraxel@bytesex.org Date: Mon, 25 Oct 2004 17:18:41 +0200 From: Gerd Knorr To: Lennert Buytenhek Cc: linux-kernel@vger.kernel.org Subject: Re: bttv hang problem on 2.6.8 Message-ID: <20041025151841.GA10042@bytesex> References: <20041025150349.GA22915@xi.wantstofly.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20041025150349.GA22915@xi.wantstofly.org> User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 956 Lines: 24 On Mon, Oct 25, 2004 at 05:03:49PM +0200, Lennert Buytenhek wrote: > (please CC on replies, I'm not on the list) > > Hi, > > When there is a background thread doing VIDIOCSYNC in a loop, issuing > VIDIOCSPICT in the current thread on the same file descriptor causes > it to go into uninterruptable sleep and hang. This is on kernel 2.6.8 > using the bttv driver, and appears easily reproducible. Don't do that. bttv serializes ioctls with a lock. Well, not all of them, but the ones which change the state of the filehandle, and both VIDIOCSYNC + VIDIOCSPICT fall into that group. You simply can't run them in parallel on the same filehandle. Gerd -- #define printk(args...) fprintf(stderr, ## args) - 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/