Re: evdev types

[Brad H. <bh...@bi...>]

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...

> > * 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 */

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.

Brad