Input: focaltech - use explicitly signed char type

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: 3bc753c06d ("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>
This commit is contained in:
Jason A. Donenfeld 2023-03-19 21:36:36 -07:00 committed by Dmitry Torokhov
parent ffa6206ebf
commit 8980f19094

View file

@ -202,8 +202,8 @@ static void focaltech_process_rel_packet(struct psmouse *psmouse,
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(struct psmouse *psmouse,
*/
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];
}
}