Re: [Ipmitool-devel] setting RTC via IPMI

[Corey M. <mi...@ac...>]

Geoff Nordli wrote:
>
> I am trying to figure out a way to set the RTC (BIOS) time remotely 
> without using NTP.
>
>  
>
> I can set the BMC clock using IPMI. 
>
>  
>
> Does anyone know of a way to set the RTC from the BMC clock?
>
Well, maybe, but not in a general case.

Some systems put the RTC on an I2C bus.  If it happens to be on an I2C 
bus that the BMC is also on, you could use the "Master Read-Write 
Command" of IPMI to perform the I2C operation.  The exact operation is 
chip-specific, of course.  Most PCs put it on the ISA bus, so it's not 
possible in that case.

In my experience, trying to find out if this is even the case is almost 
impossible.  There's usually 2 people on the planet that know (or knew) 
the information and it's almost impossible to find who they are and if 
you do they've forgotten.

You could try to write some software that scanned the I2C bus, but that 
is not completely reliable and I really don't know how to do that.

-corey