On Wed, Aug 24, 2016 at 11:29 PM, Jonathan Cameron [off-list ref] wrote:

Gregor:

quoted

So I feel like we should keep away from any temptation to define the coordinates
system too strictly.
I also think of systems composed of multiple hardware parts with sensors
scattered all over them. What would be the right "device/main hardware" reference
frame definition in these cases ?
As this is product specific, I feel like "device/main hardware" reference frame
definition should be left to the "board/main hardware/device..." implementor's
choice.

Flexible is good, but I think we should define a base rule for the chips frame
of reference and fix up any that disagree (which is nasty ABI breakage :(
Trivial choice of either right handed or left handed frame might be all we
define in general.  Useful to define consistent frames for device types that
are common perhaps as well.  (such as the screen ones Linus has here).

Admittedly I come from the mobile phone industry.

So these frames of reference is not cooked up by me, I installed the
Android app "Sensors test" to test two devices relative the world, so this
is the frame of reference used by all mobile phones and tablets on the
planet (I hardly think iPhone deviates).

I would be happy to write explicitly that for human interaction devices
with screens that frame of reference should always be assumed, but for
other uses and device types other frames of reference may apply, would
you agree?

Yours,
Linus Walleij
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