On Tue, Dec 07, 2010 at 01:40:26PM +0100, Arnd Bergmann wrote: > On Tuesday 07 December 2010, Kay Sievers wrote: > > On Tue, Dec 7, 2010 at 10:16, Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> wrote: > > > Hi Henrik, > > > > > > On Tue, Dec 07, 2010 at 08:25:26AM +0100, Henrik Rydberg wrote: > > >> Today, userspace sets up an input device based on the data it emits. > > >> This is not always enough; a tablet and a touchscreen may emit exactly > > >> the same data, for instance, but the former should be set up with a > > >> pointer whereas the latter does not need to. Recently, a new type of > > >> touchpad has emerged where the buttons are under the pad, which changes > > >> handling logic without changing the emitted data. This patch introduces > > >> a new ioctl, EVIOCGDEVINFO, which allows userspace to extract information > > >> about the device resulting in proper setup. > > > > > > If we agree that the new ioctl is suitable we'llalso need to wireit up > > > through sysfs. Also, can we keep all definitions to INPUT_ namespace? > > > > Please don't add new ioctls which are not extensible. The ioctl should > > carry the length or the version of the structure it asks for, so it > > can be extended in the future. Sysfs should be good enough for such > > interface though. > > Please never add any ioctls that have a version or length field! > > Ideally ioctls should have only scalar arguments, not structures, > so I'd recommend splitting it into two, so you can read type and > capability parameters separately. Yes, I think it is a good idea to turn it into 2 scalar ioctls. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
