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Input: focaltech - use explicitly signed char type

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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>
This commit is contained in:
Jason A. Donenfeld 2023-03-19 21:36:36 -07:00 committed by Greg Kroah-Hartman
parent 33e60ca038
commit 5262777cd2
1 changed files with 4 additions and 4 deletions
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8
drivers/input/mouse/focaltech.c
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@ -206,8 +206,8 @@ 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);
@ -222,8 +222,8 @@ 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];
}
}