HID: round return value of hidinput_calc_abs_res
authorBenjamin Tissoires <benjamin.tissoires@gmail.com>
Wed, 14 Nov 2012 15:59:14 +0000 (16:59 +0100)
committerJiri Kosina <jkosina@suse.cz>
Thu, 15 Nov 2012 09:06:56 +0000 (10:06 +0100)
hidinput_calc_abs_res should return the closest int in the division
instead of the floor.
On a device with a logical_max of 3008 and a physical_max of 255mm,
previous implementation gave a resolution of 11 instead of 12.
With 11, user-space computes a physical size of 273.5mm and the
round_closest results gives 250.6mm.
The old implementation introduced an error of 2cm in this example.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
drivers/hid/hid-input.c

index d1ec571bdb3bf1724d447ceadd8a8b6e8d7fa668..1b0adc3f780318639dca0d7745a73064f5e26af9 100644 (file)
@@ -287,7 +287,7 @@ __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code)
        }
 
        /* Calculate resolution */
-       return logical_extents / physical_extents;
+       return DIV_ROUND_CLOSEST(logical_extents, physical_extents);
 }
 EXPORT_SYMBOL_GPL(hidinput_calc_abs_res);