Devices in "single finger hybrid mode" will send one report per finger,
on some devices only the first report of such a multi-packet frame will
contain a value for BTN_LEFT, in subsequent reports (if multiple fingers
are down) the value is always 0, causing hid-mt to report BTN_LEFT going
1 - 0 - 1 - 0 when pressing a clickpad and putting down a second finger.
This happens for example on USB 0603:0002 mt touchpads.
This commit fixes this by only reporting non touch fields for the first
packet of a (possibly) multi-packet frame.
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
Changes in v4:
-New patch in this patch-set with a new approach focussed on only fixing
the issues with the USB 0603:0002 mt touchpads
---
drivers/hid/hid-multitouch.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 5d3904d0e89d..bc6a4f13c9ae 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -749,9 +749,11 @@ static int mt_touch_event(struct hid_device *hid, struct hid_field *field,
}
static void mt_process_mt_event(struct hid_device *hid, struct hid_field *field,
- struct hid_usage *usage, __s32 value)
+ struct hid_usage *usage, __s32 value,
+ bool first_packet)
{
struct mt_device *td = hid_get_drvdata(hid);
+ __s32 cls = td->mtclass.name;
__s32 quirks = td->mtclass.quirks;
struct input_dev *input = field->hidinput->input;
@@ -805,6 +807,15 @@ static void mt_process_mt_event(struct hid_device *hid, struct hid_field *field,
break;
default:
+ /*
+ * For Win8 PTP touchpads we should only look at
+ * non finger/touch events in the first_packet of
+ * a (possible) multi-packet frame.
+ */
+ if ((cls == MT_CLS_WIN_8 || cls == MT_CLS_WIN_8_DUAL) &&
+ !first_packet)
+ return;
+
if (usage->type)
input_event(input, usage->type, usage->code,
value);
@@ -825,6 +836,7 @@ static void mt_touch_report(struct hid_device *hid, struct hid_report *report)
struct mt_device *td = hid_get_drvdata(hid);
__s32 cls = td->mtclass.name;
struct hid_field *field;
+ bool first_packet;
unsigned count;
int r, n, scantime = 0;
@@ -860,6 +872,7 @@ static void mt_touch_report(struct hid_device *hid, struct hid_report *report)
}
td->prev_scantime = scantime;
+ first_packet = td->num_received == 0;
for (r = 0; r < report->maxfield; r++) {
field = report->field[r];
count = field->report_count;
@@ -869,7 +882,7 @@ static void mt_touch_report(struct hid_device *hid, struct hid_report *report)
for (n = 0; n < count; n++)
mt_process_mt_event(hid, field, &field->usage[n],
- field->value[n]);
+ field->value[n], first_packet);
}
if (td->num_received >= td->num_expected)
--
2.14.3
--
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