Re: evdev types

[Vojtech P. <vo...@su...>]

On Mon, Apr 22, 2002 at 06:19:29PM +1000, Brad Hards wrote:
> On Mon, 22 Apr 2002 17:22, Vojtech Pavlik wrote:
> > On Mon, Apr 22, 2002 at 10:04:54AM +1000, Brad Hards wrote:
> <snip>
> > You need a way to read the initial values of all absolute valuators
> > before you get any events. You may get none if the valuator doesn't
> > ever change.
> My original thinking was "Then why does the valuator matter?", but I thought 
> about it some more. A dial that indicates volume is a good example of one 
> that matters. Too much joystick thinking...

Even on joystick you have the throttle, which doesn't return into center
position automatically.

> > > * finding out about the device identity (EVIOCGNAME and EVIOCGID, maybe
> > > EVIOCGBUS if it works)
> >
> > EVIOCGBUS? What's that?
> Beats me:
> $ grep EVIOCGBUS include/linux/input.h
> #define EVIOCGBUS               _IOR('E', 0x07, short[4])               /* get 
> bus address */

Humm, don't have it in my current version, sorry. Latest version
(without your patches still) attached. (Note the interface version isn't
changed yet in it, but that's a mistake).

> I just want it to work or go away. Anyone owning up to putting it in 
> <linux/input.h>?
> 
> > > * finding out about the device features (EVIOCGBIT and EVIOCGABS)
> >
> > Add EVIOCGKEY, EVIOCGLED and EVIOCGSND to that.
> OK, added to list.
> 
> > > I think that the first element (now ->curr_value) is a different concept
> > > to the programmer compares to the rest of the features identified with
> > > EVIOCGABS.
> >
> > It's also a value you need before you start reading the events, so it's
> > handy there.
> With further thought, I think we keep it in the same ioctl. Delete the comment 
> marks. Might help stop binary breakage too.

Yes. That's right.

-- 
Vojtech Pavlik
SuSE Labs