From f0f85f5e402b89a4d9705a029b8e00b4525c5415 Mon Sep 17 00:00:00 2001 From: msizanoen Date: Sun, 19 Mar 2023 23:02:56 -0700 Subject: [PATCH] Input: alps - fix compatibility with -funsigned-char 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 Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230320045228.182259-1-msizanoen@qtmlabs.xyz Signed-off-by: Dmitry Torokhov Signed-off-by: Greg Kroah-Hartman --- drivers/input/mouse/alps.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c index 34700eda0429..3aaebadb2e13 100644 --- a/drivers/input/mouse/alps.c +++ b/drivers/input/mouse/alps.c @@ -852,8 +852,8 @@ static void alps_process_packet_v6(struct psmouse *psmouse) 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_packet_v7(struct psmouse *psmouse) ((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(struct psmouse *psmouse, int reg_pitch) 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 */