From: Thierry Reding <thierry.reding@gmail.com>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: "Rafael J . Wysocki" <rjw@rjwysocki.net>,
Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Dmitry Osipenko <digetx@gmail.com>,
Linux PM <linux-pm@vger.kernel.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
linux-tegra <linux-tegra@vger.kernel.org>
Subject: Re: [PATCH 1/2] PM / runtime: Allow drivers to override runtime PM behaviour on sleep
Date: Thu, 28 Nov 2019 17:50:26 +0100 [thread overview]
Message-ID: <20191128163623.GA2382107@ulmo> (raw)
In-Reply-To: <CAJZ5v0haOB1vc8aKk11RR-OnfLHChcqa+z7QkeKyN66s6xM3OA@mail.gmail.com>
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On Thu, Nov 28, 2019 at 05:14:51PM +0100, Rafael J. Wysocki wrote:
> On Thu, Nov 28, 2019 at 5:03 PM Thierry Reding <thierry.reding@gmail.com> wrote:
> >
> > From: Thierry Reding <treding@nvidia.com>
> >
> > Currently the driver PM core will automatically acquire a runtime PM
> > reference for devices before system sleep is entered. This is needed
> > to avoid potential issues related to devices' parents getting put to
> > runtime suspend at the wrong time and causing problems with their
> > children.
>
> Not only for that.
>
> > In some cases drivers are carefully written to avoid such issues and
> > the default behaviour can be changed to allow runtime PM to operate
> > regularly during system sleep.
>
> But this change breaks quite a few assumptions in the core too, so no,
> it can't be made.
Anything in particular that I can look at? I'm not seeing any issues
when I test this, which could of course mean that I'm just getting
lucky.
One thing that irritated me is that I think this used to work. I do
recall testing suspend/resume a few years ago and devices would get
properly runtime suspended/resumed. I did some digging but couldn't
find anything that would have had an impact on this.
Given that this is completely opt-in feature, why are you categorically
NAK'ing this?
Is there some other alternative that I can look into?
Thierry
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next prev parent reply other threads:[~2019-11-28 16:50 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-28 16:03 [PATCH 0/2] PM / runtime: Allow drivers to override runtime PM behaviour on sleep Thierry Reding
2019-11-28 16:03 ` [PATCH 1/2] " Thierry Reding
2019-11-28 16:14 ` Rafael J. Wysocki
2019-11-28 16:50 ` Thierry Reding [this message]
2019-11-28 22:03 ` Rafael J. Wysocki
2019-11-28 22:20 ` Rafael J. Wysocki
2019-11-29 10:08 ` Thierry Reding
2019-11-29 10:22 ` Rafael J. Wysocki
2019-11-29 12:07 ` Thierry Reding
2019-11-29 20:27 ` Daniel Vetter
2019-12-04 0:02 ` Rafael J. Wysocki
2019-11-29 9:33 ` Thierry Reding
2019-11-29 10:09 ` Rafael J. Wysocki
2019-11-29 11:44 ` Thierry Reding
2019-11-28 16:03 ` [PATCH 2/2] drm/tegra: Allow runtime suspend on system sleep Thierry Reding
2019-11-28 16:47 ` [PATCH 0/2] PM / runtime: Allow drivers to override runtime PM behaviour on sleep Daniel Vetter
2019-11-28 17:04 ` Thierry Reding
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