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%3Ba=su...
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@vger.kernel.org know about it.
From foo@baz Fri Mar 16 15:10:48 CET 2018
From: Hans de Goede hdegoede@redhat.com 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@redhat.com
[ 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@redhat.com Reviewed-by: Benjamin Tissoires benjamin.tissoires@redhat.com Signed-off-by: Jiri Kosina jkosina@suse.cz Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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)