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SubjectRe: [PATCH v2 0/9] PM / Domains: Add support for multi PM domains per device
On Tue, May 29, 2018 at 12:04 PM, Ulf Hansson <ulf.hansson@linaro.org> wrote:
> Changes in v2:
> - Addressed comments from Geert around DT doc.
> - Addressed comments from Jon around clarification of how to use this
> and changes to returned error codes.
> - Fixed build error in case CONFIG_PM was unset.
>
> There are devices that are partitioned across multiple PM domains. Currently
> these can't be supported well by the available PM infrastructures we have in
> the kernel. This series is an attempt to address this.
>
> The interesting parts happens from patch 5 an onwards, including a minor DT
> update to the existing power-domain bindings, the 4 earlier are just trivial
> clean-ups of some related code in genpd, which I happened to stumble over.
>
> Some additional background:
>
> One existing case where devices are partitioned across multiple PM domains, is
> the Nvida Tegra 124/210 X-USB subsystem. A while ago Jon Hunter (Nvidia) sent a
> series, trying to address these issues, however this is a new approach, while
> it re-uses the same concepts from DT point of view.
>
> The Tegra 124/210 X-USB subsystem contains of a host controller and a device
> controller. Each controller have its own independent PM domain, but are being
> partitioned across another shared PM domain for the USB super-speed logic.
>
> Currently to make the drivers work, either the related PM domains needs to stay
> powered on always or the PM domain topology needs to be in-correctly modelled
> through sub-domains. In both cases PM domains may be powered on while they
> don't need to be, so in the end this means - wasting power -.
>
> As stated above, this series intends to address these problem from a PM
> infrastructure point of view. More details are available in each changelog.
>
> It should be noted that this series has been tested on HW, however only by using
> a home-cooked test PM domain driver for genpd and together with a test driver.
> This allowed me to play with PM domain (genpd), runtime PM and device links.
>
> Any further deployment for real use cases are greatly appreciated. I am happy to
> to help, if needed!
>
> Kind regards
> Ulf Hansson
>
>
> Ulf Hansson (9):
> PM / Domains: Drop extern declarations of functions in pm_domain.h
> PM / Domains: Drop __pm_genpd_add_device()
> PM / Domains: Drop genpd as in-param for pm_genpd_remove_device()
> PM / Domains: Drop unused parameter in genpd_allocate_dev_data()
> PM / Domains: dt: Allow power-domain property to be a list of
> specifiers
> PM / Domains: Don't attach devices in genpd with multi PM domains
> PM / Domains: Split genpd_dev_pm_attach()
> PM / Domains: Add support for multi PM domains per device to genpd
> PM / Domains: Add dev_pm_domain_attach_by_id() to manage multi PM
> domains
>
> .../bindings/power/power_domain.txt | 19 ++-
> drivers/base/power/common.c | 39 ++++-
> drivers/base/power/domain.c | 155 ++++++++++++++----
> drivers/gpu/drm/amd/amdgpu/amdgpu_acp.c | 2 +-
> include/linux/pm_domain.h | 79 ++++-----
> 5 files changed, 216 insertions(+), 78 deletions(-)

I can take patches [1-4/9] from this series for 4.18.

I need an ACK from Rob on the bindings change.

The rest of the series doesn't seem to be ready yet.

Thanks,
Rafael

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