Fix bitmask bug in position reporting

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>

1 files changed, 5 insertions, 2 deletions

diff --git a/usr/src/dkms_source_tree/wacom_wac.c b/usr/src/dkms_source_tree/wacom_wac.c
index 03a3fdc..d1c388e 100644
--- a/usr/src/dkms_source_tree/wacom_wac.c
+++ b/usr/src/dkms_source_tree/wacom_wac.c
@@ -869,8 +869,11 @@ static int wacom_bbt_irq(struct wacom_wac *wacom, size_t len)
                 int p = data[9 * i + 2];
                 input_mt_slot(input, i);
                 if (p) {
-                        int x = get_unaligned_be16(&data[9 * i + 3]) << 4;
-                        int y = get_unaligned_be16(&data[9 * i + 5]) << 4;
+                        int x = get_unaligned_be16(&data[9 * i + 3]) & 0x7ff;
+                        int y = get_unaligned_be16(&data[9 * i + 5]) & 0x7ff;
+                        /* artificial scaling */
+                        x <<= 4;
+                        y <<= 4;
                         input_report_abs(input, ABS_MT_PRESSURE, p);
                         input_report_abs(input, ABS_MT_POSITION_X, x);
                         input_report_abs(input, ABS_MT_POSITION_Y, y);