This is a note to let you know that I've just added the patch titled HID: multitouch: Only look at non touch fields in first packet of a frame to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: hid-multitouch-only-look-at-non-touch-fields-in-first-packet-of-a-frame.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Fri Mar 16 15:10:48 CET 2018 From: Hans de Goede <hdegoede@xxxxxxxxxx> Date: Wed, 22 Nov 2017 12:57:09 +0100 Subject: HID: multitouch: Only look at non touch fields in first packet of a frame From: Hans de Goede <hdegoede@xxxxxxxxxx> [ Upstream commit 55746d28d66860bccaae20a67b55b9d5db7c14af ] 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> Reviewed-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> Signed-off-by: Jiri Kosina <jkosina@xxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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 65ea23be9677..397592959238 100644 --- a/drivers/hid/hid-multitouch.c +++ b/drivers/hid/hid-multitouch.c @@ -778,9 +778,11 @@ 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; @@ -837,6 +839,15 @@ 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); @@ -856,6 +867,7 @@ static void mt_touch_report(struct hid_device *hid, struct hid_report *report) { struct mt_device *td = hid_get_drvdata(hid); struct hid_field *field; + bool first_packet; unsigned count; int r, n; @@ -874,6 +886,7 @@ static void mt_touch_report(struct hid_device *hid, struct hid_report *report) td->num_expected = value; } + first_packet = td->num_received == 0; for (r = 0; r < report->maxfield; r++) { field = report->field[r]; count = field->report_count; @@ -883,7 +896,7 @@ 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) -- 2.16.2 Patches currently in stable-queue which might be from hdegoede@xxxxxxxxxx are queue-4.15/asoc-rt5651-fix-regcache-sync-errors-on-resume.patch queue-4.15/uas-fix-comparison-for-error-code.patch queue-4.15/hid-multitouch-only-look-at-non-touch-fields-in-first-packet-of-a-frame.patch