"Automatically adjust clock for daylight saving changes" option

[zaphee]

Hi.
This morning I saw that my nano didn't adjust clock for summer time.
I know that this option is useful only twice a year, but it would be nice that Rockbox could automatically adjust clock for summer time.

[roolku]

I concur. It is especially bad if you have several targets.

amiconn proposed a way to implement it the last time it happened, but I fear the idea has fallen by the wayside.

[JdGordon]

this come up twice a year and then dies very quickly

its easy to do, but its also easier to just change the clock than to code the patch and commit it

[safetydan]

The only way this could work is if you included a time zone database and a setting to set the user's current location. Then you'd have to ensure the time zone database is kept up to date with all the crazy changes that happen to time zone rules.

[JdGordon]

my feeling is that all it needs is a setting "winter time", "DST+1h", "DST+2h" which should cover everything and not need anything be kept up dated... but its hardly worth the effort

[Llorean]

Instead of including a time zone database, it seems like you could simply have two options, one of "DST begin date" and "DST end date." I don't know if internationally DST is always one hour, assuming it is, that's enough. If it's not, a third option "DST time offset" would handle the rest (or, to make the overall option more flexible, you could rename them so that a person could have their clock 'auto adjust' for a trip they're taking to a different time zone if they planned ahead).

[Febs]

Bear in mind that there are some places (Arizona, for example) that do not observe Daylight Savings Time, so there would need to be a setting to turn off DST adjustment entirely.

[Genre9mp3]

Instead of including a time zone database, it seems like you could simply have two options, one of "DST begin date" and "DST end date."

That would be a bit pointless though because DST rules don't set specific dates but have rules like "Start: Last Sunday in March - End: Last Sunday in October". This would require the user to calculate the dates every year which would be far more complex than just adjusting the time manually.

I don't know if internationally DST is always one hour

It's indeed one hour for every country that uses the DST system.

I agree with what safetydan said. The only proper way to implement this would be to maintain an up-to-date database of DST rules worldwide and let the user choose his/her location.

[JdGordon]

It's indeed one hour for every country that uses the DST system.

not always... australia did 2 hours DST in 2000 for the olympics.... there is no 1 rule

[Llorean]

Keeping a database means we need to actually keep track of DST rule changes everywhere, as they happen. We'd also be the ones yelled at if an error in the database caused someone to miss work, no matter how many places we state there's no warranty.

The advantage of "dates" rather than manually setting is that you can prepare your player in advance, rather than forgetting and having to adjust it later (which can be important for features like an alarm you depend on to go to work/class).

[safetydan]

There are free databases of time zone data available. The one that most people use is the tzdata collection available from various places and used by almost all opensource systems (and a lot of closed source). So we don't have to maintain our own database, just provide an interface to select the appropriate region and then follow the rules in the database.

[Hillshum]

Have rbutil manage the database?

[JdGordon]

my feeling is that all it needs is a setting "winter time", "DST+1h", "DST+2h" which should cover everything and not need anything be kept up dated... but its hardly worth the effort

imo ^^ is the only workable solution that doesnt need massive updating...

[soap]

my feeling is that all it needs is a setting "winter time", "DST+1h", "DST+2h" which should cover everything and not need anything be kept up dated... but its hardly worth the effort

imo ^^ is the only workable solution that doesnt need massive updating...

+1 to a "standard" database file.  (said w/o knowing squat about the impact of this method).
As for the database file itself...
I smell a RBUtil job! 

[zaphee]

my feeling is that all it needs is a setting "winter time", "DST+1h", "DST+2h" which should cover everything and not need anything be kept up dated... but its hardly worth the effort

imo ^^ is the only workable solution that doesnt need massive updating...

+1 to a "standard" database file.  (said w/o knowing squat about the impact of this method).
As for the database file itself...
I smell a RBUtil job! 

+1
Isn't it simple to just implement a summer time sheduler, so that it just adds 1 hour when switching to the summer time, and substracts 1 hour for the winter time.