From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C709C433FE for ; Mon, 24 Jan 2022 19:37:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354014AbiAXTfp (ORCPT ); Mon, 24 Jan 2022 14:35:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51790 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351890AbiAXT27 (ORCPT ); Mon, 24 Jan 2022 14:28:59 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 812A9C06135D; Mon, 24 Jan 2022 11:13:13 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 1E61E612FE; Mon, 24 Jan 2022 19:13:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF521C340E5; Mon, 24 Jan 2022 19:13:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643051592; bh=INA086hqSWtwfZHOLhkrFU+jwIwMPMlerwTlFpXtk6s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cmwWFpd+kmDXHOCvXIMIr5kG6DsVr0pQ916pnxuTed46HY1KhuIXc4GY5q/UyH5yZ tT3tWwTAIqySAyrZopS5inct2xjFgxB2HHVWaAslH9wXtaltGweLVMw8AqckkjJPxn P+pkPsKC3q3+QPfrxsDeQJeh2rqN7M/FPfVfT8W0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jason Gerecke , Ping Cheng , Jiri Kosina Subject: [PATCH 4.19 024/239] HID: wacom: Ignore the confidence flag when a touch is removed Date: Mon, 24 Jan 2022 19:41:02 +0100 Message-Id: <20220124183943.888440598@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124183943.102762895@linuxfoundation.org> References: <20220124183943.102762895@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jason Gerecke commit df03e9bd6d4806619b4cdc91a3d7695818a8e2b7 upstream. AES hardware may internally re-classify a contact that it thought was intentional as a palm. Intentional contacts are reported as "down" with the confidence bit set. When this re-classification occurs, however, the state transitions to "up" with the confidence bit cleared. This kind of transition appears to be legal according to Microsoft docs, but we do not handle it correctly. Because the confidence bit is clear, we don't call `wacom_wac_finger_slot` and update userspace. This causes hung touches that confuse userspace and interfere with pen arbitration. This commit adds a special case to ignore the confidence flag if a contact is reported as removed. This ensures we do not leave a hung touch if one of these re-classification events occured. Ideally we'd have some way to also let userspace know that the touch has been re-classified as a palm and needs to be canceled, but that's not possible right now :) Link: https://github.com/linuxwacom/input-wacom/issues/288 Fixes: 7fb0413baa7f (HID: wacom: Use "Confidence" flag to prevent reporting invalid contacts) CC: stable@vger.kernel.org Signed-off-by: Jason Gerecke Reviewed-by: Ping Cheng Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman --- drivers/hid/wacom_wac.c | 29 ++++++++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) --- a/drivers/hid/wacom_wac.c +++ b/drivers/hid/wacom_wac.c @@ -2529,6 +2529,24 @@ static void wacom_wac_finger_slot(struct } } +static bool wacom_wac_slot_is_active(struct input_dev *dev, int key) +{ + struct input_mt *mt = dev->mt; + struct input_mt_slot *s; + + if (!mt) + return false; + + for (s = mt->slots; s != mt->slots + mt->num_slots; s++) { + if (s->key == key && + input_mt_get_value(s, ABS_MT_TRACKING_ID) >= 0) { + return true; + } + } + + return false; +} + static void wacom_wac_finger_event(struct hid_device *hdev, struct hid_field *field, struct hid_usage *usage, __s32 value) { @@ -2571,9 +2589,14 @@ static void wacom_wac_finger_event(struc if (usage->usage_index + 1 == field->report_count) { - if (equivalent_usage == wacom_wac->hid_data.last_slot_field && - wacom_wac->hid_data.confidence) - wacom_wac_finger_slot(wacom_wac, wacom_wac->touch_input); + if (equivalent_usage == wacom_wac->hid_data.last_slot_field) { + bool touch_removed = wacom_wac_slot_is_active(wacom_wac->touch_input, + wacom_wac->hid_data.id) && !wacom_wac->hid_data.tipswitch; + + if (wacom_wac->hid_data.confidence || touch_removed) { + wacom_wac_finger_slot(wacom_wac, wacom_wac->touch_input); + } + } } }