[QUESTION] How to set static/dynamic dependency between clock domains

Ming Lei tom.leiming at gmail.com
Fri Dec 16 10:46:20 EST 2011

On Fri, Dec 16, 2011 at 11:13 PM, Shilimkar, Santosh
<santosh.shilimkar at ti.com> wrote:
> On Fri, Dec 16, 2011 at 7:20 PM, Ming Lei <tom.leiming at gmail.com> wrote:
>> Hi,
>> On Fri, Dec 16, 2011 at 9:24 PM, Ming Lei <tom.leiming at gmail.com> wrote:
>>> [1], add static dependency
>> Sorry for the mess, see attachment for the change.
> Your patch is setting static dependency between ISS and l3_2.
> It's not dynamic dep. Dynamic dep is managed through hardware and they

Yes, I see now,  L3_2_DYNDEP of CM_CAM_DYNAMICDEP is read only.

> are not configurable. But with static dep. you can over-ride that behavior
> as you have done.
> This will impact power since l3_2 can't idle as long as iss clock
> domain is active.
> I need to check internal code-base but I don't remember this
> issue observed so far.

In fact, I saw the issue on 3.2.0-rc5-next-20111216, and even
no such issue on 3.2.0-rc5.  After some bisecting, I found below
is the first commit on which the issue can be observed:

commit 3c50729b3fa1cd8ca1f347e6caf1081204cf1a7c
Author: Santosh Shilimkar <santosh.shilimkar at ti.com>
Date:   Wed Jan 5 22:03:17 2011 +0530

    ARM: OMAP4: PM: Initialise all the clockdomains to supported states

    Initialise hardware supervised mode for all clockdomains if it's
    supported. Initiate sleep transition for other clockdomains,
    if they are not being used.

Ming Lei

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