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Subject[ 144/187] HID: hid-multitouch: fix wrong protocol detection
Date
From: Greg KH <gregkh@linuxfoundation.org>

3.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Benjamin Tissoires <benjamin.tissoires@enac.fr>

commit 3ac36d15557d1bedfb1151d9911b9587b2d40759 upstream.

The previous implementation introduced a randomness in the splitting
of the different touches reported by the device. This version is more
robust as we don't rely on hi->input->absbit, but on our own structure.

This also prepares hid-multitouch to better support Win8 devices.

[Jiri Kosina <jkosina@suse.cz>: fix build]

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Acked-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


---
drivers/hid/hid-multitouch.c | 58 ++++++++++++++++++++++++++++++++++---------
1 file changed, 46 insertions(+), 12 deletions(-)

--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -70,9 +70,16 @@ struct mt_class {
bool is_indirect; /* true for touchpads */
};

+struct mt_fields {
+ unsigned usages[HID_MAX_FIELDS];
+ unsigned int length;
+};
+
struct mt_device {
struct mt_slot curdata; /* placeholder of incoming data */
struct mt_class mtclass; /* our mt device class */
+ struct mt_fields *fields; /* temporary placeholder for storing the
+ multitouch fields */
unsigned last_field_index; /* last field index of the report */
unsigned last_slot_field; /* the last field of a slot */
__s8 inputmode; /* InputMode HID feature, -1 if non-existent */
@@ -275,11 +282,15 @@ static void set_abs(struct input_dev *in
input_set_abs_params(input, code, fmin, fmax, fuzz, 0);
}

-static void set_last_slot_field(struct hid_usage *usage, struct mt_device *td,
+static void mt_store_field(struct hid_usage *usage, struct mt_device *td,
struct hid_input *hi)
{
- if (!test_bit(usage->hid, hi->input->absbit))
- td->last_slot_field = usage->hid;
+ struct mt_fields *f = td->fields;
+
+ if (f->length >= HID_MAX_FIELDS)
+ return;
+
+ f->usages[f->length++] = usage->hid;
}

static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
@@ -330,7 +341,7 @@ static int mt_input_mapping(struct hid_d
cls->sn_move);
/* touchscreen emulation */
set_abs(hi->input, ABS_X, field, cls->sn_move);
- set_last_slot_field(usage, td, hi);
+ mt_store_field(usage, td, hi);
td->last_field_index = field->index;
return 1;
case HID_GD_Y:
@@ -340,7 +351,7 @@ static int mt_input_mapping(struct hid_d
cls->sn_move);
/* touchscreen emulation */
set_abs(hi->input, ABS_Y, field, cls->sn_move);
- set_last_slot_field(usage, td, hi);
+ mt_store_field(usage, td, hi);
td->last_field_index = field->index;
return 1;
}
@@ -349,24 +360,24 @@ static int mt_input_mapping(struct hid_d
case HID_UP_DIGITIZER:
switch (usage->hid) {
case HID_DG_INRANGE:
- set_last_slot_field(usage, td, hi);
+ mt_store_field(usage, td, hi);
td->last_field_index = field->index;
return 1;
case HID_DG_CONFIDENCE:
- set_last_slot_field(usage, td, hi);
+ mt_store_field(usage, td, hi);
td->last_field_index = field->index;
return 1;
case HID_DG_TIPSWITCH:
hid_map_usage(hi, usage, bit, max, EV_KEY, BTN_TOUCH);
input_set_capability(hi->input, EV_KEY, BTN_TOUCH);
- set_last_slot_field(usage, td, hi);
+ mt_store_field(usage, td, hi);
td->last_field_index = field->index;
return 1;
case HID_DG_CONTACTID:
if (!td->maxcontacts)
td->maxcontacts = MT_DEFAULT_MAXCONTACT;
input_mt_init_slots(hi->input, td->maxcontacts);
- td->last_slot_field = usage->hid;
+ mt_store_field(usage, td, hi);
td->last_field_index = field->index;
td->touches_by_report++;
return 1;
@@ -375,7 +386,7 @@ static int mt_input_mapping(struct hid_d
EV_ABS, ABS_MT_TOUCH_MAJOR);
set_abs(hi->input, ABS_MT_TOUCH_MAJOR, field,
cls->sn_width);
- set_last_slot_field(usage, td, hi);
+ mt_store_field(usage, td, hi);
td->last_field_index = field->index;
return 1;
case HID_DG_HEIGHT:
@@ -385,7 +396,7 @@ static int mt_input_mapping(struct hid_d
cls->sn_height);
input_set_abs_params(hi->input,
ABS_MT_ORIENTATION, 0, 1, 0, 0);
- set_last_slot_field(usage, td, hi);
+ mt_store_field(usage, td, hi);
td->last_field_index = field->index;
return 1;
case HID_DG_TIPPRESSURE:
@@ -396,7 +407,7 @@ static int mt_input_mapping(struct hid_d
/* touchscreen emulation */
set_abs(hi->input, ABS_PRESSURE, field,
cls->sn_pressure);
- set_last_slot_field(usage, td, hi);
+ mt_store_field(usage, td, hi);
td->last_field_index = field->index;
return 1;
case HID_DG_CONTACTCOUNT:
@@ -635,6 +646,16 @@ static void mt_set_maxcontacts(struct hi
}
}

+static void mt_post_parse(struct mt_device *td)
+{
+ struct mt_fields *f = td->fields;
+
+ if (td->touches_by_report > 0) {
+ int field_count_per_touch = f->length / td->touches_by_report;
+ td->last_slot_field = f->usages[field_count_per_touch - 1];
+ }
+}
+
static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
int ret, i;
@@ -666,6 +687,13 @@ static int mt_probe(struct hid_device *h
td->maxcontact_report_id = -1;
hid_set_drvdata(hdev, td);

+ td->fields = kzalloc(sizeof(struct mt_fields), GFP_KERNEL);
+ if (!td->fields) {
+ dev_err(&hdev->dev, "cannot allocate multitouch fields data\n");
+ ret = -ENOMEM;
+ goto fail;
+ }
+
ret = hid_parse(hdev);
if (ret != 0)
goto fail;
@@ -674,6 +702,8 @@ static int mt_probe(struct hid_device *h
if (ret)
goto fail;

+ mt_post_parse(td);
+
if (!id && td->touches_by_report == 1) {
/* the device has been sent by hid-generic */
mtclass = &td->mtclass;
@@ -697,9 +727,13 @@ static int mt_probe(struct hid_device *h
mt_set_maxcontacts(hdev);
mt_set_input_mode(hdev);

+ kfree(td->fields);
+ td->fields = NULL;
+
return 0;

fail:
+ kfree(td->fields);
kfree(td);
return ret;
}



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