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 00:07:29 -0500 Message-ID: <4D3E5A91.30207@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> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4D3E59CA.6070107@teksavvy.com> 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 11-01-25 12:04 AM, Mark Lord wrote: > 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. :) 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. Cheers