[mythtv-users] Time change causes problems

[Andrew McNabb]

On Sun, Apr 03, 2005 at 08:33:17AM -0400, tcosimano at gmpexpress.net wrote:
> My time is correct but my guide data is off by an hour.  At first I 
> thought it'd done a mythfilldatabase before before the time change and 
> that had thrown it off.  I ran mythfilldatabase again but nothing is 
> changed.  It has got to be something to do with a daylight savings time 
> setting but I can't figure out where to look.

I've been looking at the code a little bit.  My hunch is that the
problem is a QT bug or a bug in libmythtv caused by a misunderstanding
of what QT is expecting.  I think it shows up somewhere in lines 77 and
78 of libmythtv/datadirect.cpp.

It's clear that the problem happens when mythfilldatabase is running.
All of the show schedules are off by an hour in the 'program' database.
The Zap2it listings that mythfilldatabase is using have the correct
times, so it's certain that the error is happening in mythfilldatabase.
The lines I pointed out are where the conversion is taking place from
UTC time to local time.

As others have pointed out, it's not a system time zone issue.  All
other programs seem to behave normally.  Some people on mythtv-users
have said that they've been able to get things to work if they use a
time-zone that doesn't switch between daylight savings and standard
time.

I ran into a page with a changelog for QT 3.3.4. [1]  Halfway down the
page it mentions a fix: "QDateTime: Fixed bug in secsTo() during
daylight savings transitions."  It doesn't give any more detail on what
the bug or the fix was, but it's possible that it's related.

Anyway, those are a couple of clues I've seen so far.  I might be way
off, but it might help someone who's trying to track this down.  Thanks
everyone!


[1] http://webcvs.kde.org/qt-copy/changes-3.3.4?rev=1.1&view=auto

-- 
Andrew McNabb
http://www.mcnabbs.org/andrew/
PGP Fingerprint: 8A17 B57C 6879 1863 DE55  8012 AB4D 6098 8826 6868
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