I vote for
Even if proc can reach halt state, I want also 125 MHz freq.
'standby' is not a happy word let say instead 'waiting input'

I think desktop proc state C4 don't fit on omap architecture

C4 on OMAP is not so deep as C6-C7 when they agree on base 0 or 1

Look closer on page 6 in my first post - 22 mW on audio decode !
and "More specifically, the OMAP3530 processor divides
its functional blocks into 18 power domains, each with its own switch. The PRCM can switch all the power
domains, but many of them can also be user-controlled."

and some definitions
C1 . MPU WFI + Core active
C2 . MPU WFI + Core inactive
C3 . MPU CSWR + Core inactive
C4 . MPU OFF + Core inactive
C5 . MPU CSWR + Core CSWR
C6 . MPU OFF + Core CSWR
C7 . MPU OFF + Core OFF

Powertop statistics don't fit omap power granularity