From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E277E258CE1 for ; Mon, 20 Oct 2025 12:43:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760964207; cv=none; b=B4uTOL08w3jocrPDxZ4wSq/aG78RQcn/uZG/xAqTPNkGR3AbZ0Xps2B5359BzuAC8dqMG8hYMDqNmwNkzzhiSypp6g/VGFaDj+XeDouFBNN3Pq1d+0evkCJBoENLckwnoGv9TUYUYVtIhUu3Tfcrk+IpnPZW1PI5D/EpskH9tnA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760964207; c=relaxed/simple; bh=wjqu4HxXWrcnrCXlwNsdCBRW602tgURiBD8P4oztI9g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=stgDZXradzkh8FrlXwauPUGIM/C4dCDcX0BIoIRDpJG1fJNt8XRa9vvmwiQSu+kyAq5jW8+a0xsF4yMEcIMOoaN8+A1vjjH8zElHJE4sgsfUZatEZ0cDdkrxmO/IyBVE7oNM/3apD1kD5LwEX5UCm/Fxmb5UOxBqA6KTLaGXhnQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=om6Loj2W; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="om6Loj2W" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6CEE4C4CEF9; Mon, 20 Oct 2025 12:43:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760964206; bh=wjqu4HxXWrcnrCXlwNsdCBRW602tgURiBD8P4oztI9g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=om6Loj2WlUw1CRSXlQU0IiKowLTZZxmK9sErC2HZhHiTmU/MdrBG+SFEuC3wW+wac sIegcbGpAAwUPlDKYOz6Qr0EzLP4d+YdRuNj88J9OSCbnf4Qm5AvTdDaGuHINXgv6z ZRWEIfJjk3OVCNS6cgA7hFYNowLHWbbwVBPVh35AtdPi/xSJvxFcGwi/6Q+XWPgX4x Cjujb8N9Tj2BU7SU8Z1CQQqdJOavxtWyQaMpSH8Vj5S0zpbhUt6vEpEe7MOMifytIP OohcRGNInueBcWEqHbL6jIC0no3U9q9buIxxk+68pLNaBAFRjNafXFDThF1KGMpNFm y4EXW4i25qIdQ== From: bentiss@kernel.org To: stable@vger.kernel.org Cc: Benjamin Tissoires , Jiri Kosina Subject: [PATCH 6.12.y] HID: multitouch: fix sticky fingers Date: Mon, 20 Oct 2025 14:43:15 +0200 Message-ID: <20251020124315.2908333-1-bentiss@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <2025102008-likewise-rubbing-d48b@gregkh> References: <2025102008-likewise-rubbing-d48b@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Benjamin Tissoires commit 46f781e0d151844589dc2125c8cce3300546f92a upstream. The sticky fingers quirk (MT_QUIRK_STICKY_FINGERS) was only considering the case when slots were not released during the last report. This can be problematic if the firmware forgets to release a finger while others are still present. This was observed on the Synaptics DLL0945 touchpad found on the Dell XPS 9310 and the Dell Inspiron 5406. Fixes: 4f4001bc76fd ("HID: multitouch: fix rare Win 8 cases when the touch up event gets missing") Cc: stable@vger.kernel.org Signed-off-by: Benjamin Tissoires Signed-off-by: Jiri Kosina Signed-off-by: Benjamin Tissoires --- drivers/hid/hid-multitouch.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c index 5c424010bc02..0667a24576fc 100644 --- a/drivers/hid/hid-multitouch.c +++ b/drivers/hid/hid-multitouch.c @@ -83,9 +83,8 @@ enum latency_mode { HID_LATENCY_HIGH = 1, }; -#define MT_IO_FLAGS_RUNNING 0 -#define MT_IO_FLAGS_ACTIVE_SLOTS 1 -#define MT_IO_FLAGS_PENDING_SLOTS 2 +#define MT_IO_SLOTS_MASK GENMASK(7, 0) /* reserve first 8 bits for slot tracking */ +#define MT_IO_FLAGS_RUNNING 32 static const bool mtrue = true; /* default for true */ static const bool mfalse; /* default for false */ @@ -160,7 +159,11 @@ struct mt_device { struct mt_class mtclass; /* our mt device class */ struct timer_list release_timer; /* to release sticky fingers */ struct hid_device *hdev; /* hid_device we're attached to */ - unsigned long mt_io_flags; /* mt flags (MT_IO_FLAGS_*) */ + unsigned long mt_io_flags; /* mt flags (MT_IO_FLAGS_RUNNING) + * first 8 bits are reserved for keeping the slot + * states, this is fine because we only support up + * to 250 slots (MT_MAX_MAXCONTACT) + */ __u8 inputmode_value; /* InputMode HID feature value */ __u8 maxcontacts; bool is_buttonpad; /* is this device a button pad? */ @@ -941,6 +944,7 @@ static void mt_release_pending_palms(struct mt_device *td, for_each_set_bit(slotnum, app->pending_palm_slots, td->maxcontacts) { clear_bit(slotnum, app->pending_palm_slots); + clear_bit(slotnum, &td->mt_io_flags); input_mt_slot(input, slotnum); input_mt_report_slot_inactive(input); @@ -972,12 +976,6 @@ static void mt_sync_frame(struct mt_device *td, struct mt_application *app, app->num_received = 0; app->left_button_state = 0; - - if (test_bit(MT_IO_FLAGS_ACTIVE_SLOTS, &td->mt_io_flags)) - set_bit(MT_IO_FLAGS_PENDING_SLOTS, &td->mt_io_flags); - else - clear_bit(MT_IO_FLAGS_PENDING_SLOTS, &td->mt_io_flags); - clear_bit(MT_IO_FLAGS_ACTIVE_SLOTS, &td->mt_io_flags); } static int mt_compute_timestamp(struct mt_application *app, __s32 value) @@ -1152,7 +1150,9 @@ static int mt_process_slot(struct mt_device *td, struct input_dev *input, input_event(input, EV_ABS, ABS_MT_TOUCH_MAJOR, major); input_event(input, EV_ABS, ABS_MT_TOUCH_MINOR, minor); - set_bit(MT_IO_FLAGS_ACTIVE_SLOTS, &td->mt_io_flags); + set_bit(slotnum, &td->mt_io_flags); + } else { + clear_bit(slotnum, &td->mt_io_flags); } return 0; @@ -1287,7 +1287,7 @@ static void mt_touch_report(struct hid_device *hid, * defect. */ if (app->quirks & MT_QUIRK_STICKY_FINGERS) { - if (test_bit(MT_IO_FLAGS_PENDING_SLOTS, &td->mt_io_flags)) + if (td->mt_io_flags & MT_IO_SLOTS_MASK) mod_timer(&td->release_timer, jiffies + msecs_to_jiffies(100)); else @@ -1734,6 +1734,7 @@ static void mt_release_contacts(struct hid_device *hid) for (i = 0; i < mt->num_slots; i++) { input_mt_slot(input_dev, i); input_mt_report_slot_inactive(input_dev); + clear_bit(i, &td->mt_io_flags); } input_mt_sync_frame(input_dev); input_sync(input_dev); @@ -1756,7 +1757,7 @@ static void mt_expired_timeout(struct timer_list *t) */ if (test_and_set_bit_lock(MT_IO_FLAGS_RUNNING, &td->mt_io_flags)) return; - if (test_bit(MT_IO_FLAGS_PENDING_SLOTS, &td->mt_io_flags)) + if (td->mt_io_flags & MT_IO_SLOTS_MASK) mt_release_contacts(hdev); clear_bit_unlock(MT_IO_FLAGS_RUNNING, &td->mt_io_flags); } -- 2.51.0