Garmin: Report correct local time offset #69
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We stupidly thought that the local time offset was in the "DEVICE_SETTINGS" message as the time_offset field. I'm pretty sure I've seen something like that before. But the FIT files from github issue #4401 clearly have that time offset field being zero, and there are two other ways to figure out what local time actually is, namely in the "local_time" field of the ACTIVITY message or the TIMESTAMP_CORRELATION message. Either of those seem to work for what we want, so let's parse both (we already did the ACTIVITY case), and let's ignore the "time_offset" field from DEVICE_SETTINGS at least if it is zero. There is probably some real explanation for what the proper way to deal with all this is, and what the whole time_offset and utc_offset fields from DEVICE_SETTINGS means, and maybe we can improve on this in the future if somebody figures it all out. In the meantime, this seems to be an improvement. Reported-by: @WetsuitSeasoning Link: subsurface/subsurface#4401 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
dirkhh
approved these changes
Dec 26, 2024
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We stupidly thought that the local time offset was in the "DEVICE_SETTINGS" message as the time_offset field. I'm pretty sure I've seen something like that before.
But the FIT files from github issue #4401 clearly have that time offset field being zero, and there are two other ways to figure out what local time actually is, namely in the "local_time" field of the ACTIVITY message or the TIMESTAMP_CORRELATION message.
Either of those seem to work for what we want, so let's parse both (we already did the ACTIVITY case), and let's ignore the "time_offset" field from DEVICE_SETTINGS at least if it is zero.
There is probably some real explanation for what the proper way to deal with all this is, and what the whole time_offset and utc_offset fields from DEVICE_SETTINGS means, and maybe we can improve on this in the future if somebody figures it all out.
In the meantime, this seems to be an improvement.
Reported-by: @WetsuitSeasoning
Link: subsurface/subsurface#4401