Set DST bit in RTC clock?

[Peter Daum]

Hi,

this is admittedly a little off-topic but I with all the BIOS-experts here,
I hope there might be somebody who knows about this:

Is there any way to modify the daylight savings time bit (see
http://www.plasma-online.de/textual/download/misc/cmos_registers.html)
of the "realtime" clock of a i386 machine running linux?

"nvramtool" won't touch the 1st 14 bytes of the CMOS. I tried changing
"hwclock" but this uses the kernel rtc driver which obviously also does
not allow to change the DST setting.

(This is of course useless for Linux - I need it in connection with
problems involving some well-known system from Redmond ...)

Any ideas?
Regards,
                              Peter

[Vladimir 'φ-coder/phcoder' Serbinenko]

On 15.05.2011 10:37, Peter Daum wrote:
> Hi,
>
> this is admittedly a little off-topic

yes it is.
> but I with all the BIOS-experts here,
> (This is of course useless for Linux - I need it in connection with
> problems involving some well-known system from Redmond ...)

Which ignores this bit as well (and uses Configuration Burial Site,
otherwise known as registry).
> Any ideas?
> Regards,
>                               Peter
>
> flashrom mailing list
> [e-mail]
> http://www.flashrom.org/mailman/listinfo/flashrom

[Peter Daum]

--- Vladimir 'φ-coder/phcoder' Serbinenko  wrote
> Which ignores this bit as well (and uses Configuration
> Burial Site, otherwise known as registry).

unfortunately not in this case: It stores time zone information and other related stuff in the registry, but if Windows (more precise: Windows XP)
thinks that the RTC clock has been adjusted to DST does not depend on the
registry (nor any other place else in the file system) and if Windows gets
this wrong it will change the RTC time (even if the setting that is
supposed to control if the time should be adjusted for DST is turned off!).

I could not find definite information about this issue anywhere and unless
I find a way to access this bit from Linux I will never know for sure, but the RTC area of the NVRAM is pretty much the only possibility left (and at
least Google found some hints of other people who suspects that some
Windows versions uses the RTC bit for this).

Why I need this is a long story but it is actually a pretty serious
problem for me. So: If anybody knows anything about this (if nothing else,
then whom else to ask; since nvramtool "almost" does what I need, this
list seems to be the only promising place) I would be very grateful ...

Regards,
                      Peter