[REG][Sensor] Catch errors when running Accelerometer.js

[xiaolongx]

Catch errors when running Accelerometer.js, this issue was fixed with #483, but reproduce again.

Error logs

acceleration (m/s^2):  x=0.004788 y=0.004788 z=0.004788
acceleration (m/s^2):  x=0.004788 y=0[ERROR] /home/xiaolong/00_xiaolong/ZJS/ww50/zephyr.js/src/zjs_callbacks.c:332 zjs_signal_callback(): error putting into ring buffer, ret=4294967174
S/ww50/zephyr.js/sracceleration (m/s^2):  x=0.004788 y=0.004788 z[ERROR] /home/xiaolong/00_xiaolong/ZJS/ww50/zephyr.js/src/zjs_callbacks.c:332 zjs_signal_callback(): error putting into ring buffer, ret=4294967174
phyr.js/sracceleration (m/s^2):  x=0.004788 y=0.004788 z=0[ERROR] /home/xiaolong/00_xiaolong/ZJS/ww50/zephyr.js/src/zjs_callbacks.c:332 zjs_signal_callback(): error putting into ring buffer, ret=4294967174
[ERROR] /home/xiaolong/00_xiaolong/ZJS/ww50/zephyr.js/src/zjs_callbacks.c:332 zjs_signal_callback(): error putting into ring buffer, ret=4294967174

Branch	Build ID	Date	Result
master	870d928	Nov 15, 2016	FAIL
master	103ca87	Nov 30, 2016	PASS
master	a162db1	Dec 6, 2016	FAIL

[jimmy-huang]

this bug appears to be a completely different issue than last one, this one seems to have been introduced by recent upgrade to the unified kernel in Zephyr, I just tried the acceleometer sample in zephyr master, and it appears it's completely broken as well, notice that it report 0.004788 on all axis, which is basically 0, 0, 0 in the zephyr sample. I think we'll have to wait for zephyr to fix the bmi160 driver first, see https://jira.zephyrproject.org/browse/ZEP-1358

[xiaolongx]

No error messages display on Arduino 101, but it report 0.004788 on all axis.
Serial logs:

Accelerometer test...
ipm_console0: 'Sensor core running ZJS ARC support image'
state: activating
state: activated
acceleration (m/s^2):  x=0.004788 y=0.004788 z=0.004788
acceleration (m/s^2):  x=0.004788 y=0.004788 z=0.004788
acceleration (m/s^2):  x=0.004788 y=0.004788 z=0.004788
acceleration (m/s^2):  x=0.004788 y=0.004788 z=0.004788
acceleration (m/s^2):  x=0.004788 y=0.004788 z=0.004788
acceleration (m/s^2):  x=0.004788 y=0.004788 z=0.004788
acceleration (m/s^2):  x=0.004788 y=0.004788 z=0.004788
acceleration (m/s^2):  x=0.004788 y=0.004788 z=0.004788

[brianjjones]

This is likely a Zephyr bug https://jira.zephyrproject.org/browse/ZEP-1358

[jimmy-huang]

two related bugs ZEP-1358 and ZEP-1421 are fixed upstream, however, the signal errors is a limitation of the our ringbuffer where it just can't handle too much signal events at a relatively fast rate like more than 30Hz, so I added a check in #604 where it will only fire event if values have changed, so hopefully this is fixed.