From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Lord Subject: Re: 2.6.36/2.6.37: broken compatibility with userspace input-utils ? Date: Tue, 25 Jan 2011 00:15:59 -0500 Message-ID: <4D3E5C8F.1080709@teksavvy.com> References: <4D3C5F73.2050408@teksavvy.com> <20110124175456.GA17855@core.coreip.homeip.net> <4D3E1A08.5060303@teksavvy.com> <20110125005555.GA18338@core.coreip.homeip.net> <4D3E4DD1.60705@teksavvy.com> <20110125042016.GA7850@core.coreip.homeip.net> <4D3E5372.9010305@teksavvy.com> <20110125045559.GB7850@core.coreip.homeip.net> <4D3E59CA.6070107@teksavvy.com> <4D3E5A91.30207@teksavvy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from ironport2-out.teksavvy.com ([206.248.154.183]:51779 "EHLO ironport2-out.pppoe.ca" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751257Ab1AYFQD (ORCPT ); Tue, 25 Jan 2011 00:16:03 -0500 In-Reply-To: <4D3E5A91.30207@teksavvy.com> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Dmitry Torokhov Cc: Linux Kernel , linux-input@vger.kernel.org On 11-01-25 12:07 AM, Mark Lord wrote: > On 11-01-25 12:04 AM, Mark Lord wrote: .. >> The EVIOCGKEYCODE ioctl is supposed to return KEY_RESERVED for unmapped >> (but value) keycodes, and only return -EINVAL when the keycode itself >> is out of range. >> >> That's how it worked in all kernels prior to 2.6.36, >> and now it is broken. It now returns -EINVAL for any unmapped keycode, >> even though keycodes higher than that still have mappings. Actually, what changed could be something different: it's possible that this bug was always there, and older kernels had a more complete default keymap for the remote than that in 2.6.36+, thereby never triggering the bug. But I don't know that, and my best efforts to-date to locate any of this in the kernel have been futile. Oh well. :) >> This is a bug, a regression, and breaks userspace. >> I haven't identified *where* in the kernel the breakage happened, >> though.. that code confuses me. :) > > Note that this device DOES have "flat scancode space", > and the kernel is now incorrectly signalling an error (-EINVAL) > in response to a perfectly valid query of a VALID (and mappable) > keycode on the remote control > > The code really is a valid button, it just doesn't have a default mapping > set by the kernel (I can set a mapping for that code from userspace and it works). > > This is a BUG. Returning -EINVAL here is entirely wrong.