From 04b4b88cca0ebe3813b4b6f014fb6a0db380b137 Mon Sep 17 00:00:00 2001 From: Vadim Zaliva Date: Wed, 10 Mar 2010 23:41:00 -0800 Subject: [PATCH] Input: appletouch - fix integer overflow issue When reading data from Geyser 2 touchpads used on post Oct 2005 Apple PowerBooks the driver was casting X and Y coordinates values to 'signed char'. Testing on one of such PowerBooks I have noticed that touchpad always generates positive values, but some of them are greater that 127, and thus, when cast to 'signed char' being interpreted as a negative. Such bigger values have been observed infrequently, closer to the edges of a touchpad, so the problem was not very visible. Nevertheless, the patch would potentially improve touchpad driver accuracy. Signed-off-by: Vadim Zaliva Signed-off-by: Dmitry Torokhov --- drivers/input/mouse/appletouch.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/input/mouse/appletouch.c b/drivers/input/mouse/appletouch.c index 908b5b44052f..53ec7ddd1826 100644 --- a/drivers/input/mouse/appletouch.c +++ b/drivers/input/mouse/appletouch.c @@ -205,8 +205,8 @@ struct atp { bool overflow_warned; int x_old; /* last reported x/y, */ int y_old; /* used for smoothing */ - signed char xy_cur[ATP_XSENSORS + ATP_YSENSORS]; - signed char xy_old[ATP_XSENSORS + ATP_YSENSORS]; + u8 xy_cur[ATP_XSENSORS + ATP_YSENSORS]; + u8 xy_old[ATP_XSENSORS + ATP_YSENSORS]; int xy_acc[ATP_XSENSORS + ATP_YSENSORS]; int idlecount; /* number of empty packets */ struct work_struct work; @@ -531,7 +531,7 @@ static void atp_complete_geyser_1_2(struct urb *urb) for (i = 0; i < ATP_XSENSORS + ATP_YSENSORS; i++) { /* accumulate the change */ - signed char change = dev->xy_old[i] - dev->xy_cur[i]; + int change = dev->xy_old[i] - dev->xy_cur[i]; dev->xy_acc[i] -= change; /* prevent down drifting */ -- 2.20.1