From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [RFC] Input: define separate EVIOCGKEYCODE_V2/EVIOCSKEYCODE_V2 Date: Thu, 9 Dec 2010 11:16:47 -0800 Message-ID: <20101209191647.GC23781@core.coreip.homeip.net> References: <20101209093948.GD8821@core.coreip.homeip.net> <4D012844.3020009@euromail.se> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <4D012844.3020009@euromail.se> Sender: linux-media-owner@vger.kernel.org To: Henrik Rydberg Cc: Linux Input , LKML , linux-media@vger.kernel.org, Mauro Carvalho Chehab , Jiri Kosina , Jarod Wilson , David =?iso-8859-1?Q?H=E4rdeman?= List-Id: linux-input@vger.kernel.org On Thu, Dec 09, 2010 at 08:04:36PM +0100, Henrik Rydberg wrote: > On 12/09/2010 10:39 AM, Dmitry Torokhov wrote: > > > The desire to keep old names for the EVIOCGKEYCODE/EVIOCSKEYCODE while > > extending them to support large scancodes was a mistake. While we tried > > to keep ABI intact (and we succeeded in doing that, programs compiled > > on older kernels will work on newer ones) there is still a problem with > > recompiling existing software with newer kernel headers. > > > > New kernel headers will supply updated ioctl numbers and kernel will > > expect that userspace will use struct input_keymap_entry to set and > > retrieve keymap data. But since the names of ioctls are still the same > > userspace will happily compile even if not adjusted to make use of the > > new structure and will start miraculously fail in the field. > > > > To avoid this issue let's revert EVIOCGKEYCODE/EVIOCSKEYCODE definitions > > and add EVIOCGKEYCODE_V2/EVIOCSKEYCODE_V2 so that userspace can explicitly > > select the style of ioctls it wants to employ. > > > > Signed-off-by: Dmitry Torokhov > > --- > > > Would the header change suffice in itself? We still need to change evdev to return -EINVAL on wrong sizes but yes, the amount of change there could be more limited. I just thought that splitting it up explicitly shows the differences in handling better. If people prefer the previos version we could leave it, I am 50/50 between them. > Either way, also checked that the > bugfixes following the original patch is still in effect, so looks ok to me. Thanks. -- Dmitry