From: msizanoen msizanoen@qtmlabs.xyz
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@qtmlabs.xyz Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230320045228.182259-1-msizanoen@qtmlabs.xyz Signed-off-by: Dmitry Torokhov dmitry.torokhov@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 */