From: Jason A. Donenfeld Jason@zx2c4.com
commit 8980f190947ba29f23110408e712444884b74251 upstream.
The recent change of -funsigned-char causes additions of negative numbers to become additions of large positive numbers, leading to wrong calculations of mouse movement. Change these casts to be explicitly signed, to take into account negative offsets.
Fixes: 3bc753c06dd0 ("kbuild: treat char as always unsigned") Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Reviewed-by: Hans de Goede hdegoede@redhat.com Cc: stable@vger.kernel.org Link: https://bugzilla.kernel.org/show_bug.cgi?id=217211 Link: https://lore.kernel.org/r/20230318133010.1285202-1-Jason@zx2c4.com Signed-off-by: Dmitry Torokhov dmitry.torokhov@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/input/mouse/focaltech.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
--- a/drivers/input/mouse/focaltech.c +++ b/drivers/input/mouse/focaltech.c @@ -202,8 +202,8 @@ static void focaltech_process_rel_packet state->pressed = packet[0] >> 7; finger1 = ((packet[0] >> 4) & 0x7) - 1; if (finger1 < FOC_MAX_FINGERS) { - state->fingers[finger1].x += (char)packet[1]; - state->fingers[finger1].y += (char)packet[2]; + state->fingers[finger1].x += (s8)packet[1]; + state->fingers[finger1].y += (s8)packet[2]; } else { psmouse_err(psmouse, "First finger in rel packet invalid: %d\n", finger1); @@ -218,8 +218,8 @@ static void focaltech_process_rel_packet */ finger2 = ((packet[3] >> 4) & 0x7) - 1; if (finger2 < FOC_MAX_FINGERS) { - state->fingers[finger2].x += (char)packet[4]; - state->fingers[finger2].y += (char)packet[5]; + state->fingers[finger2].x += (s8)packet[4]; + state->fingers[finger2].y += (s8)packet[5]; } }