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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7558FC433F5 for ; Fri, 7 Sep 2018 17:35:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2B34A2075E for ; Fri, 7 Sep 2018 17:35:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="G6+B9bUd" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2B34A2075E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727698AbeIGWRJ (ORCPT ); Fri, 7 Sep 2018 18:17:09 -0400 Received: from mail-pf1-f195.google.com ([209.85.210.195]:39651 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726543AbeIGWRH (ORCPT ); Fri, 7 Sep 2018 18:17:07 -0400 Received: by mail-pf1-f195.google.com with SMTP id j8-v6so7343365pff.6; Fri, 07 Sep 2018 10:35:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=IjX6ru9EF51TP19f4jfIgUkVjFK+B9XjIAX845dcbzs=; b=G6+B9bUdPqX3/iL91cmTKQqZPAEsaHcsNKaFukxFzuMp4T3DUwsDoGzTx7SSMGUcJO SSO+LzbT96oNpzFUiN/pFev4R58GuFbumG0KUxtY/tMw8KQ2B/FtoKjKLBGzMIZOTb5c mqqgUW8DmAv2Hd3scm9hC6w2qQDF7RWfVVahGZ3avhCYMTl0lPFYaPEbi1QKwkoFUbtZ 8HDemJFN+vDvogH/EWG4YkHFdYuHv8SH61FV/+n1iDSMPN15TNjkqB4I+FAxct0komzD SZEkcnJI3QTP5dAdfQn91PTYq5K5iZfv5FCzi0y+0vHaDSNvSwoJoK7DlbHZIc+YGajE 3W2g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=IjX6ru9EF51TP19f4jfIgUkVjFK+B9XjIAX845dcbzs=; b=O2Ma8mb3P3u+tbcaHYNzqWpmv/s+9TqQDMAXZd+9+MeLFTO9fXMw7L7r1DoEwviCmr PShXI4kCBnmDs/j9XUlJyqE+Wtv/QnTIkMbdCzZTr4qCxJ3hxGi9dJ/30BJVA4qGY8q1 Te91aulxUApB1n2hxa7m9YzwI3AryPNtWEGffNSD5PkrKtKeTywzOEsI+wn46AvRhWBV TYvcM7Ga0KT8JuTO5JbldVg0uRkWq7YY0JRX8SFVyzA51FzmYmVxqvA/Pq9TefwjnY+o YJXhlWZvL8ZbWL9Q5w1V9KAZWJOwG+cSympOK/44PWFaG6/gDnTo9c1l4sIZ406r1z1B 6QJw== X-Gm-Message-State: APzg51C0dk6cjXSVrp+OhC04tGfN7JY7VgL2X35WMnIAET1UxWIGooU8 r3rUu0ZSrmN6B7FvmCUjEXM= X-Google-Smtp-Source: ANB0VdbioKx51LCzgksALb4NMJ+IUEUCa5qTYF6dGKtjcshtPmP9BQOYgYubFKgz/JEUY/1GTeoI1w== X-Received: by 2002:a63:d150:: with SMTP id c16-v6mr9478060pgj.188.1536341709202; Fri, 07 Sep 2018 10:35:09 -0700 (PDT) Received: from dtor-ws ([2620:15c:202:201:3adc:b08c:7acc:b325]) by smtp.gmail.com with ESMTPSA id e14-v6sm10927877pff.128.2018.09.07.10.35.07 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 07 Sep 2018 10:35:07 -0700 (PDT) Date: Fri, 7 Sep 2018 10:35:05 -0700 From: Dmitry Torokhov To: Benjamin Tissoires Cc: Jiri Kosina , Harry Cutts , Peter Hutterer , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, Benjamin Tissoires Subject: Re: [PATCH] Input: reserve 2 events code because of HID Message-ID: <20180907173505.GA261528@dtor-ws> References: <20180907085115.30242-1-benjamin.tissoires@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180907085115.30242-1-benjamin.tissoires@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 07, 2018 at 10:51:15AM +0200, Benjamin Tissoires wrote: > From: Benjamin Tissoires > > Prior to commit 190d7f02ce8e ("HID: input: do not increment usages when > a duplicate is found") from the v4.18 kernel, HID used to shift the > event codes if a duplicate usage was found. This ended up in a situation > where a device would export a ton of ABS_MISC+n event codes, or a ton > of REL_MISC+n event codes. > > This is now fixed, however userspace needs to detect those situation. > Fortunately, ABS_MISC+1 was never assigned a code, and so libinput > can detect fake multitouch devices from genuine ones by checking is > ABS_MISC+1 is set. > > Now that we have REL_WHEEL_HI_RES, libinput won't be able to differentiate > true high res mice from some other device in a pre-v4.18 kernel. > > Set in stone that the ABS_MISC+1 and REL_MISC+1 are reserved and should not > be used so userspace can properly work around those old kernels. > > Signed-off-by: Benjamin Tissoires > --- > > Hi, > > while reviewing my local tree, I realize that we might want to be able > to differentiate older kernels from new ones that export REL_WHEEL_HI_RES. > > I know Dmitry was against adding several REL_MISC, so I hope just moving > REL_WHEEL_HI_RES by one and reserving the faulty event codes would be good > this time. > > This patch applies on top of the branch for-4.20/logitech-highres from > Jiri's tree. It should go through Jiri's tree as well. Hm, this is a bit ugly, bit I guess we could spare an event code. Acked-by: Dmitry Torokhov > > Cheers, > Benjamin > > include/uapi/linux/input-event-codes.h | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/include/uapi/linux/input-event-codes.h b/include/uapi/linux/input-event-codes.h > index 29fb891ea337..30149939249a 100644 > --- a/include/uapi/linux/input-event-codes.h > +++ b/include/uapi/linux/input-event-codes.h > @@ -708,7 +708,12 @@ > #define REL_DIAL 0x07 > #define REL_WHEEL 0x08 > #define REL_MISC 0x09 > -#define REL_WHEEL_HI_RES 0x0a > +/* > + * 0x0a is reserved and should not be used. > + * It was used by HID as REL_MISC+1 and usersapce needs to detect if > + * the next REL_* event is correct or is just REL_MISC + n. > + */ > +#define REL_WHEEL_HI_RES 0x0b > #define REL_MAX 0x0f > #define REL_CNT (REL_MAX+1) > > @@ -745,6 +750,12 @@ > > #define ABS_MISC 0x28 > > +/* > + * 0x29 is reserved and should not be used. > + * It was used by HID as ABS_MISC+1 and usersapce needs to detect if > + * the next ABS_* event is correct or is just ABS_MISC + n. > + */ > + > #define ABS_MT_SLOT 0x2f /* MT slot being modified */ > #define ABS_MT_TOUCH_MAJOR 0x30 /* Major axis of touching ellipse */ > #define ABS_MT_TOUCH_MINOR 0x31 /* Minor axis (omit if circular) */ > -- > 2.14.3 > -- Dmitry