Re: [Qemu-devel] Changing RTC from UTC to local time

[Bartosz Fabianowski <bartosz@fabianowski.de>]

> Er, no.  For a _Windows_ PC, this is true.  For all *BSD and Linux 
> OSes, you should usually use UTC/GMT for the hardware clock.

You can set a PC's RTC to UTC or any other time zone for that matter if 
you want to. However, according to the original design (dating back to 
the olden days of the first IBM PC), the RTC should be running in local 
time.

I don't run Linux myself but since so many people multi-boot Windows and 
Linux, I guess it must be possible to make Linux deal with an RTC 
running in local time, even if the Linux default is UTC. As for *BSD, it 
is definitely possible to do so. I run FreeBSD as my primary OS and I 
know that during installation it already asks you whether your RTC has 
local or UTC time. So it can deal with both scenarios.

Thus, since Linux and *BSD are flexible and can deal with both the 
standard local and non-standard UTC setting, while Windows only 
understands local time, I believe that setting the RTC to local time 
will make it usable to all those systems at once.

> Please revert the patch or make it so that it is a runtime option.  I 
> don't run Windows in QEMU and this makes all my times off.

I guess one could make this a runtime option. But that would only 
clutter the command line, as there would be one more parameter just to 
set the RTC's time zone. A compile time option makes much more sense 
IMHO. However, this would only benefit very few people as most people 
download binaries.

Keeping in mind that Linux and *BSD both can deal with a standard PC RTC 
running in local time, are you sure that QEMU really needs the option of 
having the RTC run in UTC?

Regards,
- Bartosz Fabianowski