From mboxrd@z Thu Jan 1 00:00:00 1970 From: Clinton Sprain Subject: Re: USB keyboard occasional key stuck Date: Mon, 17 Feb 2014 20:08:50 -0600 Message-ID: <5302C0B2.9010506@gmail.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-yk0-f169.google.com ([209.85.160.169]:34714 "EHLO mail-yk0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751221AbaBRCQg (ORCPT ); Mon, 17 Feb 2014 21:16:36 -0500 In-Reply-To: Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Daniel J Blueman , linux-usb@vger.kernel.org, linux-input@vger.kernel.org Cc: Dmitry Torokhov I noticed your examples are both fn combos. I'm seeing something like this and it seems specifically related to the fn key. Reproducible on a Macbook (3,1) and a Lenovo Yoga 13. Sequence is simple: Press key Press fn Release key Release fn The key will be 'stuck' until you press another key. It seems to only apply to keys that are part of a fn combo, so affected keys vary from one model to another; it appears that if nothing is mapped to fn+key on a given hardware, the key is not affected. For example, delete is affected on the Macbook (which has fn+delete = backspace), but not on the Yoga (which has a dedicated backspace key). Arrow keys are an exception to this rule though. Is this what you're seeing? - Clinton On 02/17/2014 07:23 AM, Daniel J Blueman wrote: > Across 5+ years of kernels, I've been seeing occasional (1-2 times per > day) key-stuck issues where eg a fn+delete combo repeats delete until > I press delete again. I've seen this happen with fn+ctrl+left, leaving > left held and likewise with right. > > This has occurred on Apple laptops, external USB keyboards and Dell > laptops, so seems like a linux USB input issue, as I haven't seen > occur on Windows or MacOS on the same hardware. > > It seems a good move for me to rebuild and run a kernel with some USB > HID instrumentation to locate this issue over time. Without apriori > knowledge of the linux USB input stack, what is a good initial > approach? > > Thanks, > Daniel