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From: Juergen Beisert <jbe@pengutronix.de>
To: linux-kernel@vger.kernel.org
Subject: Strange results of DIV_ROUND_CLOSEST
Date: Tue, 18 Dec 2012 16:03:41 +0100	[thread overview]
Message-ID: <201212181603.42094.jbe@pengutronix.de> (raw)

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/  |

             reply	other threads:[~2012-12-18 15:06 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-18 15:03 Juergen Beisert [this message]
2012-12-18 17:16 ` Guenter Roeck
2012-12-18 21:04   ` Juergen Beisert
2012-12-18 22:59     ` Guenter Roeck
2012-12-19  1:45     ` Guenter Roeck
2012-12-19  7:32       ` Juergen Beisert

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