Re: Using EV_MSC or extending KEY_*

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Thu, Sep 17, 2009 at 02:57:07PM -0300, Henrique de Moraes Holschuh wrote:
> On Wed, 16 Sep 2009, Rick L. Vinyard, Jr. wrote:
> > The M* keys are intended to provide a quick way to switch between key
> > mappings, with each mode having their own user-defined mappings.
> 
> What I'd do in this case would be this:
> 
> 1. Initially have the M* level-shift keys assigned KEY_RESERVED
> 
> 2. Have a big enough keymap to map all keys in all M*-level shift states
> possible.
> 
> Eg:
>    START OF KEYMAP
>    M* keys
>    1st set of G* keys
>    2nd set of G* keys
>    3rd set of G* keys...
>    ...
>    last set of G* keys
>    END OF KEYMAP
> 
> 3. Have the driver special-process M* level-shift keys *as long as they are
> still set to KEY_RESERVED* to select which part of the keymap is used to
> translate the other keys.  Note that this likely means pressing a M* key
> would be transparent to userspace in this case, i.e. no events would be
> issued when a M* key is doing a level shift.
> 
> So, you'd be able to set all mappings you want in the driver, and the M*
> keys would do what they're expected to do without any userland help at all,
> but you'd still be able to program the M* keys to be normal keys if you
> want.
> 
> Of course, this assumes you don't do chording on multiple M* keys to end up
> with a huge number of keymaps :p
> 

Actually I think that the device should just emit KEY_PROG1..KEY_PROG4
for the M keys and have userspace daemon load alternate keymaps on the
fly in resaponse to KEY_PROGx. The device is just a set of completely
generic buttons... User will have to tell the kernel what to map them
to.

-- 
Dmitry