linux-kernel - Re: [PATCH v2 1/3] phy: core: Move runtime PM reference counting to the parent device

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Date:   Sat, 23 Dec 2017 02:50:12 +0100
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Ulf Hansson <ulf.hansson@...aro.org>,
        Kishon Vijay Abraham I <kishon@...com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Linux PM <linux-pm@...r.kernel.org>,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>
Subject: Re: [PATCH v2 1/3] phy: core: Move runtime PM reference counting to
 the parent device

On Sat, Dec 23, 2017 at 2:35 AM, Rafael J. Wysocki <rafael@...nel.org> wrote:
> On Thu, Dec 21, 2017 at 11:50 AM, Ulf Hansson <ulf.hansson@...aro.org> wrote:
>> On 21 December 2017 at 02:39, Rafael J. Wysocki <rafael@...nel.org> wrote:
>>> On Wed, Dec 20, 2017 at 3:09 PM, Ulf Hansson <ulf.hansson@...aro.org> wrote:
>>>> The runtime PM deployment in the phy core is deployed using the phy core
>>>> device, which is created by the phy core and assigned as a child device of
>>>> the phy provider device.

[cut]

>>
>> Also, I have considered how to deal with wakeup paths for phys,
>> although I didn't want to post changes as a part of this series, but
>> maybe I should to give a more complete picture?
>
> Yes, you should.
>
> The point is that without genpd using pm_runtime_force_suspend() the
> phy code could very well stay the way it is.  And it is logical,
> because having a parent with enabled runtime PM without enabling
> runtime PM for its children is at least conceptually questionable.

Actually, I sort of agree that the phy's usage of runtime PM is too
convoluted.  For example, it uses pm_runtime_enabled() unnecessarily
at least in some places, but that doesn't seem to be fixed by your
patches.

Thanks,
Rafael