efirtc + atrtc at the same time

I see that on my laptop both efirtc and atrtc get attached.
The latter is via an ACPI attachment:
efirtc0: <EFI Realtime Clock>
efirtc0: registered as a time-of-day clock, resolution 1.000000s
atrtc0: <AT realtime clock> port 0x70-0x71 on acpi0
atrtc0: registered as a time-of-day clock, resolution 1.000000s

I am not sure if this is a problem by itself, but it certainly seems redundant
to have two drivers controlling the same(?) hardware via different platform
mechanisms.
Maybe there is a nice way to automatically disable (or "neutralize") one of the
drivers?

Also, there is another issue related to atrtc.
When I have both drivers attached, and also when I have only atrtc attached
(efi.rt.disabled=1), system clock jumps 10 minutes forward after each suspend /
resume cycle (S0 -> S3 -> S0).  That does not happen for reboot and shutdown
cycles.  I haven't investigated this deeper, but it is a curious problem.

-- 
Andriy Gapon