Re: [PATCH RFC 3/4] input: add a EV_SW event for ratchet switch

[Mauro Carvalho Chehab <mchehab@s-opensource.com>]

Em Tue, 28 Mar 2017 10:25:17 +1000
Peter Hutterer <peter.hutterer@who-t.net> escreveu:

> On Mon, Mar 27, 2017 at 09:27:31AM -0300, Mauro Carvalho Chehab wrote:
> > Em Mon, 27 Mar 2017 11:53:57 +1000
> > Peter Hutterer <peter.hutterer@who-t.net> escreveu:
> >   
> > > On Sat, Mar 25, 2017 at 07:49:41PM -0300, Mauro Carvalho Chehab wrote:  
> > > > Some mouses have a switch on their wheel, allowing to switch
> > > > between ratchet or free wheel mode. Add support for it.    
> > > 
> > > I understand the want to support it because it's there but what do you
> > > expect this to be used for?
> > > 
> > > tbh, I wouldn't know what to do with this information, short of displaying
> > > some OSD to inform the user. Which is rather superfluous since the physical
> > > change will feel obvious anyway.  
> > 
> > For this particular device, the main reason is because it is there :-)
> > As adding support for it is trivial, I don't see any reason why not
> > adding it.
> > 
> > Yet, applications could use it, in order to switch between a "discrete" 
> > mode, where one wheel position corresponds to one line of scroll, and
> > movements below a threshold would be ignored.  
> 
> fwiw, that would more likely be the  result of receiving a different event
> code (hires-wheel), more so than a ratchet switch - at least on this device.

Yeah, that would be another alternative.

> the mice I have here don't change the behaviour of the wheel, so the
> granularity is the same before and after. But they also don't send events
> for the state, so there's that :)

Another alternative would be that applications could be listening to
EV_SW SW_RATCHET event. When the switch changes to free wheel, it could
be enabling high-resolution mode.

Thanks,
Mauro