Re: [PATCH 1/2] ARM: OMAP3: PM: remove superfluous calls to pwrdm_clear_all_prev_pwrst()

On Tue, Jan 31, 2012 at 1:19 PM, Paul Walmsley [off-list ref] wrote:

On Tue, 31 Jan 2012, Shilimkar, Santosh wrote:

quoted

A week back I was discussing with Benoit and Tony about having some
infrastructure like "unused clocks" so that we can shutdown those
modules, and if possible some power domains. That way they get
removed at one single place and they the power domain calls
need not iterate over the once which are no longer needed.

Sure, if you have some ideas, that sounds promising.  I'd assume the main
performance issues would be related to global PRCM register reads, rather
than raw CPU cycles.  So that's probably where it would make sense to
focus the effort.

I fully agree that PRCM register read time is the main issue.
Would discuss this with Benoit and Rajendra bit more on what we
can be done.

We should also be able to optimize out a fair number of the powerdomain
register reads if we cache them in the struct powerdomain.  The current
powerstate and next powerstate seem to be hit a lot, and those should both
be cacheable.  Will probably do some of this as part of the functional
powerstate code.

PD register caching seems to be a good optimization.

Regards
Santosh
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