# Re: \[PATCH\] HID: logitech-dj: add support for the static device in the Powerplay mat/receiver

- From: Jiri Kosina \<jikos@kernel.org\>
- Date: 2020-03-10 13:22:22 
- List: linux-input
- Page: https://ratatoskr.run/linux-input/2020/03/5890434
- Thread: https://ratatoskr.run/linux-input/2020/01/5831978/t.md

```text
On Wed, 12 Feb 2020, Filipe Laíns wrote:

> > > +	/* custom receiver device (eg. powerplay) */
> > > +	if (hidpp_report->device_index == 7) {
> > > +		workitem.reports_supported |= HIDPP;
> > > +	}
> > > +
> > 
> > I guess we can't do anything else than to trust Logitech that they will 
> > not assign conflicting device_index ID in the future to something that 
> > will not be HID++, right?
> > 
> > Or is this properly documented somewhere?
> > 
> > Thanks,
> 
> 
> CCing Nestor
> 
> Yes, we need to trust Logitech on this. There's isn't anything
> documented regarding this AFAIK.
> 
> Even if Logitech released a device with index 7 that didn't support
> HID++, it wouldn't be that big of an issue. We would just end up with a
> hidraw node which would export a vendor page report descriptor but the
> device wouldn't actually reply to anything.

Given the silence from Nestor, I guess we can just apply this for 5.7; 
pushing to for-5.7/logitech branch.

Thanks,

-- 
Jiri Kosina
SUSE Labs

```