Commit ccd32e73 authored Mar 21, 2011 by Vivien Didelot Committed by Jean Delvare Mar 21, 2011

hwmon: (sht15) Fix integer overflow in humidity calculation

An integer overflow occurs in the calculation of RHlinear when the
relative humidity is greater than around 30%. The consequence is a subtle
(but noticeable) error in the resulting humidity measurement.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: stable@kernel.org
Cc: Jonathan Cameron <jic23@cam.ac.uk>

parent 396bd766

drivers/hwmon/sht15.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -333,11 +333,11 @@ static inline int sht15_calc_humid(struct sht15_data *data)

		const int c1 = -4;
		const int c2 = 40500; /* x 10 ^ -6 */
		const int c3 = -2800; /* x10 ^ -9 */
		const int c3 = -28; /* x 10 ^ -7 */

		RHlinear = c1*1000
		+ c2 * data->val_humid/1000
		+ (data->val_humid * data->val_humid * c3)/1000000;
		+ (data->val_humid * data->val_humid * c3) / 10000;
		return (temp - 25000) * (10000 + 80 * data->val_humid)
		/ 1000000 + RHlinear;
		}