From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Slaby Subject: Re: [PATCH 1/7 v3] HID: magicmouse: don't allow hidinput to initialize the device Date: Thu, 02 Sep 2010 11:28:06 +0200 Message-ID: <4C7F6E26.2030301@gmail.com> References: <1283306184-28833-1-git-send-email-chase.douglas@canonical.com> <1283306184-28833-2-git-send-email-chase.douglas@canonical.com> <4C7E94F6.9050806@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-fx0-f46.google.com ([209.85.161.46]:34683 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751677Ab0IBJ2K (ORCPT ); Thu, 2 Sep 2010 05:28:10 -0400 In-Reply-To: Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Michael Poole Cc: Chase Douglas , Jiri Kosina , Henrik Rydberg , Tejun Heo , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org On 09/02/2010 01:57 AM, Michael Poole wrote: > Jiri Slaby wrote: >> This looks weird. Is there any past discussion about why you cannot use >> hidinput and you have to do all the input bits yourself while cheating >> this very weird way? > > The Magic Mouse and Magic Trackpad do not publish HID descriptors for > the multitouch reports. Given the variable-length report packets -- > and especially the Magic Trackpad's new, mutant DOUBLE_REPORT_ID > packets -- it would be non-trivial to write accurate descriptors that > the HID core can use. (Someone wrote a patch to try that a few months > ago. It ended up adding significantly more lines to hid-magicmouse.c > than it removed, and it was not obvious to me that it got the Report > Count fields correct.) Ok, makes sense. The proper solution is to call a driver hook in hidinput_connect to do the mapping instead of report parsing done there, right? (And not setting [gs]etkeycode in that case.) Then the part of magicmouse_setup_input starting at the first __set_bit will be exactly the hook. Otherwise this hack looks like a hard cross-layer breakage. /me wonders how HID issuers are creative in breaking standards. regards, -- js