From: msizanoen <msizanoen@xxxxxxxxxxx>
commit 754ff5060daf5a1cf4474eff9b4edeb6c17ef7ab upstream.
The AlpsPS/2 code previously relied on the assumption that `char` is a
signed type, which was true on x86 platforms (the only place where this
driver is used) before kernel 6.2. However, on 6.2 and later, this
assumption is broken due to the introduction of -funsigned-char as a new
global compiler flag.
Fix this by explicitly specifying the signedness of `char` when sign
extending the values received from the device.
Fixes: f3f33c677699 ("Input: alps - Rushmore and v7 resolution support")
Signed-off-by: msizanoen <msizanoen@xxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20230320045228.182259-1-msizanoen@xxxxxxxxxxx
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/input/mouse/alps.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
--- a/drivers/input/mouse/alps.c
+++ b/drivers/input/mouse/alps.c
@@ -852,8 +852,8 @@ static void alps_process_packet_v6(struc
x = y = z = 0;
/* Divide 4 since trackpoint's speed is too fast */
- input_report_rel(dev2, REL_X, (char)x / 4);
- input_report_rel(dev2, REL_Y, -((char)y / 4));
+ input_report_rel(dev2, REL_X, (s8)x / 4);
+ input_report_rel(dev2, REL_Y, -((s8)y / 4));
psmouse_report_standard_buttons(dev2, packet[3]);
@@ -1104,8 +1104,8 @@ static void alps_process_trackstick_pack
((packet[3] & 0x20) << 1);
z = (packet[5] & 0x3f) | ((packet[3] & 0x80) >> 1);
- input_report_rel(dev2, REL_X, (char)x);
- input_report_rel(dev2, REL_Y, -((char)y));
+ input_report_rel(dev2, REL_X, (s8)x);
+ input_report_rel(dev2, REL_Y, -((s8)y));
input_report_abs(dev2, ABS_PRESSURE, z);
psmouse_report_standard_buttons(dev2, packet[1]);
@@ -2294,20 +2294,20 @@ static int alps_get_v3_v7_resolution(str
if (reg < 0)
return reg;
- x_pitch = (char)(reg << 4) >> 4; /* sign extend lower 4 bits */
+ x_pitch = (s8)(reg << 4) >> 4; /* sign extend lower 4 bits */
x_pitch = 50 + 2 * x_pitch; /* In 0.1 mm units */
- y_pitch = (char)reg >> 4; /* sign extend upper 4 bits */
+ y_pitch = (s8)reg >> 4; /* sign extend upper 4 bits */
y_pitch = 36 + 2 * y_pitch; /* In 0.1 mm units */
reg = alps_command_mode_read_reg(psmouse, reg_pitch + 1);
if (reg < 0)
return reg;
- x_electrode = (char)(reg << 4) >> 4; /* sign extend lower 4 bits */
+ x_electrode = (s8)(reg << 4) >> 4; /* sign extend lower 4 bits */
x_electrode = 17 + x_electrode;
- y_electrode = (char)reg >> 4; /* sign extend upper 4 bits */
+ y_electrode = (s8)reg >> 4; /* sign extend upper 4 bits */
y_electrode = 13 + y_electrode;
x_phys = x_pitch * (x_electrode - 1); /* In 0.1 mm units */
