Daylight Savings Time

[Daniel Taylor]

This was brought up in the Wish List thread.

 

If I recall correctly, there is a check box somewhere in Windows operating systems that tells the computer whether to change the time when DST changes.  I suspect that Linux might have the same thing.  Does the B2 have a way to select that and pass it through to the Raspberry Pi OS?

[Daniel Taylor]

I asked this question because it has been reported that various members' B2s failed to change time on the DST date.

Well, since there have been no responses to my question, I decided to do some research.  I Googled "how does Linux handle daylight savings time" and the first response gave me some solid info.  Apparently, Linux operating systems can indeed handle DST.  The HWCLOCK must be set (with the -u switch) to UTC.  And there must exist a zoneinfo file (in the right location) that contains (at least) the info for your timezone:  does that timezone acknowledge DST, and if so, on which days does the time change.  So, as one would expect, Linux has it covered.

The remaining questions are these:  Does the B2's Raspberry Pi implementation leave this cabability intact?  Does the B2 come with a correct zoneinfo file in the proper location?  And does the B2 allow the user to turn DST on/off?

Does anybody have any further insight into this?

[Edwyn Corteen]

Hi Daniel

The B2 "knows" only what the time is in GMT, it does not currently know what your offset is from GMT or when to change the time according to daylight saving in your area, this is top of my wish list!

Wether this can be made available only Martin can tell us as the B2 does not have a full Linux distribution, but from your googling it does seem simple to implement.

[Daniel Taylor]

Thanks much, Edwyn. 

[Tony]

The Linux system that runs the B2 is built using something called Buildroot . 

Earlier this year, I did a little programming project to enable an ssh server on the B2.  Martin kindly provided the config files for Builtroot that I needed in order make that happen and I shared the result to this group as a patch file that you could be installed without needed support or integration from Brennan Inc. 

I just took a look at the build file for the B2 version of Buildroot and the TZ (timezone) package is not one of the selected option.  A quick google search suggests that's what is needed to implement automatic daylight savings time adjustment.

I suppose that I could rebuild the Buildroot stuff and see if I can make a patch file to fix the issue.  But that path is fraught with peril so it would be better if Martin rebuilt it.  

Having said that, I'm don't know if the B2 update function can update the core OS stuff or just the B2 task itself?

[JustAnOrdinaryJoanna]

My car 'does not know' what the time is, per Edwyn's comment. What it does have in the settings, is a toggle switch for daylight savings. When the clocks go forward or back, I check/uncheck the box as appropriate & the job is done & the clock reflects the right time by adding, or not, 1 hour. It's certainly better than fiddling with the clock. Could that be a simple solution?