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Re: [sensors] Reporting mode and polling frequency

From: Tobie Langel via GitHub <sysbot+gh@w3.org>
Date: Fri, 28 Oct 2016 13:08:18 +0000
To: public-device-apis-log@w3.org
Message-ID: <issue_comment.created-256915708-1477660097-sysbot+gh@w3.org>
> Reporting mode can be different for same sensor type, even on the 
same platform.

Note that the reporting mode distinctions the spec makes are not the 
same as the ones the Android platform makes.

The spec has the following:

- periodic: requires a frequency,
- non-periodic: which is basically whatever the implementor wants to 
do (can be periodic, can be on change, whatever).

Periodic reporting mode is required for doing anything useful with 
low-level motion sensors. It is not for the rest of sensors.

I'd like to hear more details about the motion sensors which don't 
provide continuous data on Windows, so we can decide what to do with 
those. The main question being to see whether or not such sensors 
would actually enable the use cases we care about.

> Frequency is always used except for special sensors e.g. trigger.

As mentioned 
[above](https://github.com/w3c/sensors/issues/126#issuecomment-256632571),
 what you're passing Android `On Change` sensors isn't polling 
frequency. We should not conflate these two things.

In the case where setting frequency is needed (for dumb sensor that 
are polled) but is not a developer requirement (afaik, everything but 
motion sensors), the polling frequency is best left implementation 
specific. In a subsequent version of the spec, we can add further 
hints to help the UA pick a better polling strategy, but that's not a 
requirement for level 1. **There are no requirements for setting the 
frequency of non motion sensors for now.** Furthermore, there are 
explicit warnings against doing so from other stakeholders (e.g. 
@gmandyam).

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Received on Friday, 28 October 2016 13:08:24 UTC

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