On Sun, 29 Aug 2021 at 17:54, Dmitry Baryshkov
[off-list ref] wrote:

On Sun, 29 Aug 2021 at 06:51, Stephen Boyd [off-list ref] wrote:

quoted

Quoting Dmitry Baryshkov (2021-08-26 14:56:23)

quoted

On 26/08/2021 21:31, Stephen Boyd wrote:

quoted

Quoting Dmitry Baryshkov (2021-07-27 13:19:56)

quoted

On SM8250 both the display and video clock controllers are powered up by
the MMCX power domain. Handle this by linking clock controllers to the
proper power domain, and using runtime power management to enable and
disable the MMCX power domain.

Dependencies:
- https://lore.kernel.org/linux-arm-msm/20210703005416.2668319-1-bjorn.andersson@linaro.org/ (local)
   (pending)

Does this patch series need to go through the qcom tree? Presumably the
dependency is going through qcom -> arm-soc

It looks like Bjorn did not apply his patches in the for-5.15 series, so
we'd have to wait anyway. Probably I should rebase these patches instead
on Rajendra's required-opps patch (which is going in this window).

Ok. Thanks. I'll drop it from my queue for now.

Just for the reference. I've sent v7 of this patchset. After thinking
more about power domains relationship, I think we have a hole in the
abstraction here. Currently subdomains cause power domains to be
powered up, but do not dictate the performance level the parent domain
should be working in.

That's not entirely true. In genpd_add_subdomain() we verify that if
the child is powered on, the parent must already be powered on,
otherwise we treat this a bad setup and return an error code.

What seems to be missing though, is that if there is a performance
state applied for the child domain, that should be propagated to the
parent domain too. Right?

While this does not look like an issue for the
gdsc (and thus it can be easily solved by the Bjorn's patches, which
enforce rpmhpd to be powered on to 'at least lowest possible'
performance state, this might be not the case for the future links. I
think at some point the pd_add_subdomain() interface should be
extended with the ability to specify minimum required performance
state when the link becomes on.

I guess that minimum performance state could be considered as a
"required-opp" in the DT node for the power-domain provider, no?

Another option would simply be to manage this solely in the
platform/soc specific genpd provider. Would that work?

Until that time I have changed code to
enforce having clock controller in pm resume state when gdsc is
enabled, thus CC itself votes on parent's (rpmhpd) performance state.


--
With best wishes
Dmitry

Kind regards
Uffe