From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755213Ab2LRPGh (ORCPT ); Tue, 18 Dec 2012 10:06:37 -0500 Received: from metis.ext.pengutronix.de ([92.198.50.35]:44950 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754834Ab2LRPGg (ORCPT ); Tue, 18 Dec 2012 10:06:36 -0500 From: Juergen Beisert Organization: Pengutronix - Linux Solutions for Science and Industry To: linux-kernel@vger.kernel.org Subject: Strange results of DIV_ROUND_CLOSEST Date: Tue, 18 Dec 2012 16:03:41 +0100 User-Agent: KMail/1.9.10 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <201212181603.42094.jbe@pengutronix.de> X-SA-Exim-Connect-IP: 2001:6f8:1178:4:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: jbe@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi list, commit 263a523d18bca306016d75f5c8d5c57c37fe52fb changes the code of DIV_ROUND_CLOSEST in include/linux/kernel.h to fix a compile time warning. But now feeding in a zero into this macro results into 4198403. Tested with gcc 4.4.3 and 4.7.2, on arch x86 and ARM. I can reproduce this behaviour, when my ADC delivers a '0' value in the driver drivers/hwmon/s3c-hwmon.c in function s3c_hwmon_ch_show() with a current 3.7.1 kernel. The value is correct again, when the ADC delivers at least a '1'. Any ideas how to fix it correctly? jbe -- Pengutronix e.K. | Juergen Beisert | Linux Solutions for Science and Industry | http://www.pengutronix.de/ |