| From 507e2fbaaacb6f164b4125b87c5002f95143174b Mon Sep 17 00:00:00 2001 |
| From: Ian Dall <ian@beware.dropbear.id.au> |
| Date: Wed, 11 Feb 2009 13:04:46 -0800 |
| Subject: w1: w1 temp calculation overflow fix |
| |
| From: Ian Dall <ian@beware.dropbear.id.au> |
| |
| commit 507e2fbaaacb6f164b4125b87c5002f95143174b upstream. |
| |
| Addresses http://bugzilla.kernel.org/show_bug.cgi?id=12646 |
| |
| When the temperature exceeds 32767 milli-degrees the temperature overflows |
| to -32768 millidegrees. These are bothe well within the -55 - +125 degree |
| range for the sensor. |
| |
| Fix overflow in left-shift of a u8. |
| |
| Signed-off-by: Ian Dall <ian@beware.dropbear.id.au> |
| Signed-off-by: Evgeniy Polyakov <zbr@ioremap.net> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| drivers/w1/slaves/w1_therm.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/drivers/w1/slaves/w1_therm.c |
| +++ b/drivers/w1/slaves/w1_therm.c |
| @@ -113,7 +113,7 @@ static struct w1_therm_family_converter |
| |
| static inline int w1_DS18B20_convert_temp(u8 rom[9]) |
| { |
| - s16 t = (rom[1] << 8) | rom[0]; |
| + int t = ((s16)rom[1] << 8) | rom[0]; |
| t = t*1000/16; |
| return t; |
| } |
