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 CCE26C433F5 for ; Mon, 22 Nov 2021 00:38:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229594AbhKVAlM (ORCPT ); Sun, 21 Nov 2021 19:41:12 -0500 Received: from devianza.investici.org ([198.167.222.108]:23939 "EHLO devianza.investici.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229884AbhKVAlM (ORCPT ); Sun, 21 Nov 2021 19:41:12 -0500 Received: from mx2.investici.org (unknown [127.0.0.1]) by devianza.investici.org (Postfix) with ESMTP id 4Hy7fP0D09z6vKN for ; Mon, 22 Nov 2021 00:38:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=autistici.org; s=stigmate; t=1637541485; bh=V0q5B9qvFgFTMXb14QZ53bTj5TQQreE3P/KfmW8Ctu4=; h=From:To:Subject:Date:From; b=AozxmWQDeyMr2BhNifLOyxSVtbDAdx9iJ1vtMkjNgIB888AeEB6stKl33Qk9rRGVe bMahP/YYFCt4EvB5I4DmSXBbXoLKqUIq47JYWKxm0owJ8g4U+tZm6tBKoYGg+ob1ND z4eHk4OjgTYaEfd8KsEWpRd1GG0dg7T64LYInbA8= Received: from [198.167.222.108] (mx2.investici.org [198.167.222.108]) (Authenticated sender: andrea.monaco@autistici.org) by localhost (Postfix) with ESMTPSA id 4Hy7fN6DBVz6vKF for ; Mon, 22 Nov 2021 00:38:04 +0000 (UTC) From: Andrea Monaco To: linux-input@vger.kernel.org Subject: i2c_hid: Possible workaround to Synaptics touchpad going wild on Acer Aspire Date: Mon, 22 Nov 2021 01:38:03 +0100 Message-ID: <87ee79f2j8.fsf@autistici.org> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org Hello, as I wrote in previous emails to this list, my Synaptics touchpad (SYN1B7F) on Acer Aspire laptop sometimes starts acting wild, it moves and clicks and drags on its own. I can't find any trigger for this behavior, it just happens. I see long sequences of HID reports that are identical expect for the timestamp when this happens; my hypothesis is that the issue is on the hardware, possibly a buggy firmware of the touchpad. Unloading and reloading i2c_hid solves the issue, probably because it triggers a hardware reset of the device. So I came up with a possible workaround: any time the kernel detects two consecutive HID reports that are identical except for the timestamp, it hard resets the device. The user would experience a very brief discontinuity in mouse response, still much better than current behavior. This particular hack could be activated with an option to the relevant module(s), or when the affected touchpad models are found. Any comments or suggestions? Warmly, Andrea Monaco