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 00:04:10 -0500 Message-ID: <4D3E59CA.6070107@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> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20110125045559.GB7850@core.coreip.homeip.net> Sender: linux-kernel-owner@vger.kernel.org To: Dmitry Torokhov Cc: Linux Kernel , linux-input@vger.kernel.org List-Id: linux-input@vger.kernel.org On 11-01-24 11:55 PM, Dmitry Torokhov wrote: > On Mon, Jan 24, 2011 at 11:37:06PM -0500, Mark Lord wrote: .. >> This results in (map->size==10) for 2.6.36+ (wrong), >> and a much larger map->size for 2.6.35 and earlier. >> >> So perhaps EVIOCGKEYCODE has changed? >> > > So the utility expects that all devices have flat scancode space and > driver might have changed so it does not recognize scancode 10 as valid > scancode anymore. > > The options are: > > 1. Convert to EVIOCGKEYCODE2 > 2. Ignore errors from EVIOCGKEYCODE and go through all 65536 iterations. or 3. Revert/fix the in-kernel regression. 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. 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. :) Thanks.