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HID: magicmouse: palm rejection for the T6041 (M4 Max) trackpad #636

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Merged
RyanTheTide merged 1 commit into from
Nov 5, 2026
Merged

HID: magicmouse: palm rejection for the T6041 (M4 Max) trackpad #636

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86 changes: 79 additions & 7 deletions drivers/hid/hid-magicmouse.c
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Original file line number Diff line number Diff line change
Expand Up @@ -263,6 +263,9 @@ struct effect_job {
* @quirks: Currently unused.
* @query_dimensions: Whether to query and update dimensions on first open
* @mtp_c1fe: Whether the MTP trackpad sends the J700 C1FE report layout.
* @mtp_palms: Whether the controller's contact classes are trusted for palms
* on the standard MTP report (T6041).
* @mtp_palm_ids: MTP contact IDs reported as palms until they lift.
* @ntouches: Number of touches in most recent touch report.
* @scroll_accel: Number of consecutive scroll motions.
* @scroll_jiffies: Time of last scroll motion.
Expand All @@ -289,6 +292,8 @@ struct magicmouse_sc {
unsigned long quirks;
bool query_dimensions;
bool mtp_c1fe;
bool mtp_palms;
DECLARE_BITMAP(mtp_palm_ids, U8_MAX + 1);

int ntouches;
int scroll_accel;
Expand Down Expand Up @@ -963,12 +968,55 @@ static void report_c1fe_finger_data(struct input_dev *input, int slot,
static bool magicmouse_haptic_click(struct magicmouse_sc *msc, u32 pressure,
bool firmware_button);

/*
* The T6041 (M4 Max) MTP trackpad's records carry the contact ID and state in
* the first word and the controller's class in the low byte of the second: 1
* for a thumb, 2 and 3 for fingers, 6 and above for palms. Recorded on a J616C:
* moving fingers had a tool area of 830-1010 and class 2 or 3, a resting thumb
* ~1750 and class 1, a resting palm ~2040 and class 7; palms dragged across the
* pad reached 5100. The class flickers while a hand lands, so a contact counts
* as a palm once the controller classes it as one with a tool area no finger
* reaches, or once its tool area passes palm size, and stays a palm until it
* lifts. Thumbs stay touches.
*/
#define MAGICMOUSE_MTP_PALM_CLASS_MIN 6
#define MAGICMOUSE_MTP_CLASSED_PALM_TOOL_MAJOR 1400
#define MAGICMOUSE_MTP_PALM_TOOL_MAJOR 2200

static u8 magicmouse_mtp_contact_id(const struct tp_finger *f)
{
return le16_to_cpu(f->unknown1) & 0xff;
}

static void magicmouse_mtp_update_palms(struct magicmouse_sc *msc,
const u8 *records, int count)
{
DECLARE_BITMAP(palms, U8_MAX + 1);
const struct tp_finger *f;
int i, tool;
u8 id, class;

bitmap_zero(palms, U8_MAX + 1);
for (i = 0; i < count; i++) {
f = (const struct tp_finger *)(records + i * sizeof(*f));
id = magicmouse_mtp_contact_id(f);
class = le16_to_cpu(f->unknown2) & 0xff;
tool = le16_to_int(f->tool_major);
if (tool > MAGICMOUSE_MTP_PALM_TOOL_MAJOR ||
(class >= MAGICMOUSE_MTP_PALM_CLASS_MIN &&
tool > MAGICMOUSE_MTP_CLASSED_PALM_TOOL_MAJOR) ||
test_bit(id, msc->mtp_palm_ids))
__set_bit(id, palms);
}
bitmap_copy(msc->mtp_palm_ids, palms, U8_MAX + 1);
}

static void report_finger_data(struct input_dev *input, int slot,
const struct input_mt_pos *pos,
const struct tp_finger *f)
const struct tp_finger *f, int tool)
{
input_mt_slot(input, slot);
input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
input_mt_report_slot_state(input, tool, true);

input_report_abs(input, ABS_MT_TOUCH_MAJOR,
le16_to_int(f->touch_major) << 1);
Expand Down Expand Up @@ -1025,6 +1073,10 @@ static int magicmouse_raw_event_mtp(struct hid_device *hdev,
return 0;
}

if (msc->mtp_palms)
magicmouse_mtp_update_palms(msc, data + hdr_sz,
tp_hdr->num_fingers);

n = 0;
for (i = 0; i < tp_hdr->num_fingers; i++) {
f = (struct tp_finger *)(data + hdr_sz + i * touch_sz);
Expand All @@ -1047,7 +1099,13 @@ static int magicmouse_raw_event_mtp(struct hid_device *hdev,
if (msc->mtp_c1fe) {
report_c1fe_finger_data(input, msc->tracking_ids[i], &msc->pos[i]);
} else {
report_finger_data(input, msc->tracking_ids[i], &msc->pos[i], f);
int tool = MT_TOOL_FINGER;

if (msc->mtp_palms &&
test_bit(magicmouse_mtp_contact_id(f), msc->mtp_palm_ids))
tool = MT_TOOL_PALM;
report_finger_data(input, msc->tracking_ids[i], &msc->pos[i],
f, tool);
pressure += le16_to_int(f->pressure);
}
}
Expand Down Expand Up @@ -1315,13 +1373,20 @@ static int magicmouse_setup_input_mtp(struct input_dev *input,
* nothing that user space would take for a touch size or a pressure.
*/
if (!msc->mtp_c1fe) {
/*
* A palm's tool area on the T6041 trackpad exceeds 5000 once
* scaled, so allow the full range of the record's 16-bit fields
* there.
*/
int area_max = msc->mtp_palms ? 2 * S16_MAX : 5000;

/* finger touch area */
input_set_abs_params(input, ABS_MT_TOUCH_MAJOR, 0, 5000, 0, 0);
input_set_abs_params(input, ABS_MT_TOUCH_MINOR, 0, 5000, 0, 0);
input_set_abs_params(input, ABS_MT_TOUCH_MAJOR, 0, area_max, 0, 0);
input_set_abs_params(input, ABS_MT_TOUCH_MINOR, 0, area_max, 0, 0);

/* finger approach area */
input_set_abs_params(input, ABS_MT_WIDTH_MAJOR, 0, 5000, 0, 0);
input_set_abs_params(input, ABS_MT_WIDTH_MINOR, 0, 5000, 0, 0);
input_set_abs_params(input, ABS_MT_WIDTH_MAJOR, 0, area_max, 0, 0);
input_set_abs_params(input, ABS_MT_WIDTH_MINOR, 0, area_max, 0, 0);

input_set_abs_params(input, ABS_MT_PRESSURE, 0, 6000, 0, 0);

Expand All @@ -1338,6 +1403,11 @@ static int magicmouse_setup_input_mtp(struct input_dev *input,
J314_TP_MAX_FINGER_ORIENTATION, 0, 0);
}

/* The T6041 controller classifies palms. */
if (msc->mtp_palms)
input_set_abs_params(input, ABS_MT_TOOL_TYPE, 0, MT_TOOL_MAX,
0, 0);

/* Note: Touch Y position from the device is inverted relative
* to how pointer motion is reported (and relative to how USB
* HID recommends the coordinates work). This driver keeps
Expand Down Expand Up @@ -2323,6 +2393,8 @@ static int magicmouse_probe(struct hid_device *hdev,
/* The J700 trackpad sends a different report layout. */
np = of_get_child_by_name(dev_of_node(hdev->dev.parent), "multi-touch");
msc->mtp_c1fe = of_device_is_compatible(np, "apple,j700-multitouch");
msc->mtp_palms = !msc->mtp_c1fe &&
of_machine_is_compatible("apple,t6041");
of_node_put(np);

msc->input_ops.raw_event = magicmouse_raw_event_mtp;
Expand Down