From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [RFC][PATCH] input: Introduce device information ioctl Date: Tue, 7 Dec 2010 08:48:12 -0800 Message-ID: <20101207164811.GA25344@core.coreip.homeip.net> References: <1291706726-8835-1-git-send-email-rydberg@euromail.se> <20101207162222.GA32237@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pw0-f46.google.com ([209.85.160.46]:38088 "EHLO mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750916Ab0LGQs2 (ORCPT ); Tue, 7 Dec 2010 11:48:28 -0500 Content-Disposition: inline In-Reply-To: <20101207162222.GA32237@kroah.com> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Greg KH Cc: Henrik Rydberg , Jiri Kosina , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, Ping Cheng , Chris Bagwell On Tue, Dec 07, 2010 at 08:22:22AM -0800, Greg KH wrote: > On Tue, Dec 07, 2010 at 08:25:26AM +0100, Henrik Rydberg wrote: > > /** > > + * struct input_devinfo - device information via EVIOCGDEVINFO ioctl > > + * @types: bitmask of types (DEVTYPE_*) matching this device > > + * @capabilities: bitmask of capabilities (DEVCAPS_*) of this device > > + * > > + * This struct provides information about the device needed for > > + * automatic setup in userspace, such as if the device is direct > > + * (touchscreen) or indirect (touchpad), and if there are other > > + * special considerations, such as the touchpad also being a button. > > + */ > > +struct input_devinfo { > > + __u32 types; > > + __u32 capabilities; > > +}; > > Why use an ioctl for this at all? It's just 2 simple values that don't > need to be atomically read at the same time. What's wrong with 2 more > sysfs files? > Because if you already dealing with a file descriptor ioctl is much more convenient. Sysfs can be nice (and that is why we'll add it as well) but it is not a recipe for the world peace. -- Dmitry