Just to add to this, when I test SENSOR_HRM, the timestamps are from CLOCK_MONOTONIC, but timestamps for SENSOR_PRESSURE are over a minute behind CLOCK_MONOTONIC and the offset seems to be increasing every time I run the test. So to summarize:
SENSOR_HRM timestamps are from CLOCK_MONOTONIC. SENSOR_PRESSURE is almost CLOCK_MONOTONIC, but not really. SENSOR_ACCELEROMETER is... I have no idea, but nothing usable. -Max On Thu, Dec 29, 2016 at 11:25 AM, Maxim Khitrov <m...@bhsai.org> wrote: > Hi, > > I posted about this on the developer forum and JIRA back in August, > but got nowhere. The original Gear S2 firmware used CLOCK_MONOTONIC > for sensor event timestamps. The next firmware (DPG1) changed this to > CLOCK_REALTIME. The new firmware (EPK5) that was released a few weeks > ago changed the source yet again, only this time I don't have a clue > what it's using and I can't find the relevant source at > https://review.tizen.org/git/. > > Here's logcat output from a small native test program: > > 12-29 10:29:19.827 : CLOCK_MONOTONIC: 153936923042954 > 12-29 10:29:19.862 : CLOCK_REALTIME: 1483025359862936528 > 12-29 10:29:27.222 : [00] t=18446744073694551 > 12-29 10:29:27.222 : [01] t=225000(-18446744073.470) > 12-29 10:29:27.222 : [02] t=465000(+0.240) > 12-29 10:29:27.227 : [03] t=705000(+0.240) > 12-29 10:29:27.227 : [04] t=946000(+0.241) > > The first two lines are the current time values obtained using > clock_gettime, followed by 5 acceleration events at a rate of 250 ms. > What am I looking at? Yes, I get that the last four values are > relative times in microseconds (even though the docs still say > nanoseconds). > > The first timestamp is always the same, so it's not even an actual > time value, which makes it very difficult to convert these times to > UTC or to compare them with timestamps from other sensors. I also have > no idea whether these values are going to be affected by jumps in the > UTC clock or not. Can anyone explain what is happening here and > whether there is some hope of a stable API in the future? > > -Max _______________________________________________ Dev mailing list Dev@lists.tizen.org https://lists.tizen.org/listinfo/dev
