Re: Poll rate change and closing indication to polled input device

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

On Fri, Oct 09, 2009 at 01:12:02PM +0100, Mark Brown wrote:
> On Fri, Oct 09, 2009 at 03:02:59PM +0300, Onkalo Samu wrote:
> 
> > I would like to change the polling rate of the polled input device
> > on the fly depending on the use case. One possible way is to directly
> > modify poll_interval from my driver. However, I would like to introduce
> > functions which can be used to set / get polling rate like 
> 
> > input_polled_device_set_rate(...)
> 
> > input_polled_device_get_rate(...)
> 
> > Another missing thing is an indication when the polled device is closed.
> > This can be used to turn off the HW which is not used anymore.
> 

The reason that this is missing is because polled devices are expected
to be extremely dumb. Since even many interrupt-driven devices can't be
shut off I did not expect that polled devices would need it.

> > What do you think, is it ok to introduce these additions to the polled
> > input device?
> 
> It'd be really good to have this control exposed to user space in a
> standard fashion.

I'll take the patches.

>  Other devices that generate constant data rates like
> touchscreens could also benefit from it, changing their output rate
> depending on the needs of user space to give a power saving.

Not sure if this belongs to the input core as such. It seems that what
you want here is dynamic power-management which works on the level below
input core (individual devices on particular buses).

-- 
Dmitry