- From: Tobie Langel via GitHub <sysbot+gh@w3.org>
- Date: Sat, 25 Jun 2016 08:14:44 +0000
- To: public-device-apis@w3.org
> If there already exists an instance that is already polling at some frequency _f_, all new instances will be polling at the same frequency _f_ That's a misunderstanding of what the spec says. The idea here is that everyone is listening to the same physical sensor and that this physical sensor is polled with the intent of fulfilling the highest frequency requirements. Hence, if context A requires 100Hz, context B requires 200Hz, and context C requires 1.2KHz, and the hardware sensor can't handle more than 1KHz, then all three contexts will get 1KHz. Note there is no guarantee that this frequency will be maintained or even possible. Now consider context C is no longer interested in getting sensor readings: A and B will get 200Hz. I can imagine you can use sensor frequency to transfer data between origins or across browsers by doing the following: Listener would set frequency to something low, say 50Hz. Emitter would use high and low frequency to transfer information (e.g. 800Hz for `1` and 200Hz for `0`). You could even imagine the Listener peaking to 1KHz to ack Emitter's message. Note that, unless I'm mistaken, the threat here is mostly limited to cross-browser tracking as I suspect there are much simpler solution to transfer information between collaborating parties with different origins from within the same browser. -- GitHub Notification of comment by tobie Please view or discuss this issue at https://github.com/w3c/sensors/issues/100#issuecomment-228522358 using your GitHub account
Received on Saturday, 25 June 2016 08:14:47 UTC