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utcdstopenembeddedyoctoreal-time-clock

DST doesn't work on an Embedded linux distribution (without network connection)

I've been trying to set up the DST on an embedded linux, which has intalled a Yocto Project/OpenEmbedded linux distribution.

The first step was to check if the symbolic link from /etc/localtime to /usr/share/zoneinfo/Europe/Paris was set up. 

ln -s /usr/share/zoneinfo/Europe/Paris /etc/localtime

Then the next step seemed to be to knew if the RTC was set up to UTC. Community suggested to check on the file /etc/sysconfig/clock. Unfortunatley, there isn't such a file on this distribution.

Now, two questions come to my mind: First, exist any other way to check if the RTC is on UTC? Second, Considering a Poky/OpenEmbedded distribution is made by the junction of custom packages, which packages are needed in order to perform a DST?

Solution

  • Without knowing which packages your image consists of, it's kinda hard to answer.

    Though, at least if you're using busybox-hwclock to set the system clock from the RTC, the hwclock.sh script checks for an UTC variable defined in /etc/default/rcS.

    That and the two files /etc/localtime and /etc/timezone ought to be enough. You could also check if TZ is being set (though, /etc/localtime has normally replaced setting TZ).