linux-kernel - Re: [PATCH] PM / runtime: Drop children check from __pm_runtime_set

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Date:   Tue, 5 Dec 2017 16:48:46 +0100
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
Cc:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Linux PM <linux-pm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Alan Stern <stern@...land.harvard.edu>,
        USB list <linux-usb@...r.kernel.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
        Kishon Vijay Abraham I <kishon@...com>
Subject: Re: [PATCH] PM / runtime: Drop children check from __pm_runtime_set_status()

On 5 December 2017 at 04:23, Yoshihiro Shimoda
<yoshihiro.shimoda.uh@...esas.com> wrote:
> Hi,
>
>> From: Ulf Hansson, Sent: Monday, December 4, 2017 7:41 PM
>>
>> On 1 December 2017 at 12:03, Yoshihiro Shimoda
>> <yoshihiro.shimoda.uh@...esas.com> wrote:
> <snip>
>> > Sure! I tested your patch, and then the following message disappeared!
>> >
>> >    Enabling runtime PM for inactive device (ee080200.usb-phy) with active children
>>
>> Great, that confirms my theory.
>>
>> I will re-work the patch and re-post it to see what people thinks about it.
>
> Thank you!
>
>> >
>> > However, the following message still exists.
>> >
>> >    Enabling runtime PM for inactive device (ee080000.usb) with active children
>> >
>> > So, I guess ohci-platform.c also has similar issue.
>>
>> Yes, very likely!
>>
>> However, I need some more time to look into this to be able to suggest
>> a solution.
>
> I found a solution and sent a report as below:
> https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1551146.html
>
> What do you think about using pm_runtime_forbid()?

As both Alan and Rafael pointed out in their replies, this is not the
right solution.

However, what is indeed interesting is how it can silence the error
messages. I keep this is mind while later moving forward.

Kind regards
Uffe