From: Ulf Hansson <ulf.hansson@linaro.org>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Linux PM <linux-pm@vger.kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Alan Stern <stern@rowland.harvard.edu>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux ACPI <linux-acpi@vger.kernel.org>,
Linux PCI <linux-pci@vger.kernel.org>,
Linux Documentation <linux-doc@vger.kernel.org>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Kevin Hilman <khilman@kernel.org>
Subject: Re: [PATCH v3 1/6] PM / core: Add LEAVE_SUSPENDED driver flag
Date: Fri, 17 Nov 2017 16:57:05 +0100 [thread overview]
Message-ID: <CAPDyKFpXh=E8vC9fUXhbDTLcekb74xfd7chTyKKSw1VgPv1rCQ@mail.gmail.com> (raw)
In-Reply-To: <CAJZ5v0iD3uzJr4fdhrWfRhSmr_foU4GQx9LY_9sR=BKYUxZOGw@mail.gmail.com>
On 17 November 2017 at 15:31, Rafael J. Wysocki <rafael@kernel.org> wrote:
> On Fri, Nov 17, 2017 at 2:49 PM, Ulf Hansson <ulf.hansson@linaro.org> wrote:
>> [...]
>>
>>>>
>>>>>> Second, have you considered setting the default value of
>>>>>> dev->power.may_skip_resume to true?
>>>>>
>>>>> Yes.
>>>>>
>>>>>> That would means the subsystem
>>>>>> instead need to implement an opt-out method. I am thinking that it may
>>>>>> not be an issue, since we anyway at this point, don't have drivers
>>>>>> using the LEAVE_SUSPENDED flag.
>>>>>
>>>>> Opt-out doesn't work because of the need to invoke the "noirq" callbacks.
>>>>
>>>> I am not sure I follow that.
>>>>
>>>> Whatever needs to be fixed on the subsystem level, that could be done
>>>> before the driver starts using the LEAVE_SUSPENDED flag. No?
>>>
>>> That requires a bit of explanation, sorry for being overly concise.
>>>
>>> The core calls ->resume_noirq from the middle layer regardless of
>>> whether or not the device will be left suspended, so the
>>> ->resume_noirq cannot do arbitrary things to it. Setting
>>> may_skip_resume by the middle layer tells the core that the middle
>>> layer is ready for that and is going to cooperate. If may_skip_resume
>>> had been set by default, that piece of information would have been
>>> missing.
>>
>> Huh, I still don't get that. Sorry.
>>
>> If the "may_skip_resume" is default set to true by the PM core,
>> wouldn't that just mean that the middle-layer needs to implement an
>> opt-out method, rather than opt-in. In principle to opt-out the
>> middle-layer needs to set may_skip_resume to false in suspend_noirq
>> phase, no?
>
> Yes, but if the middle-layer doesn't clear it, that may mean two
> things. First, the middle layer is ready and so on. Good. Second,
> the middle layer is not aware of the whole thing. Not good. The core
> cannot tell.
>
> In the opt-in case, however, all is clear. :-)
Okay.
>
>> Then we only need to make sure drivers don't starts use
>> LEAVE_SUSPENDED, before we make sure the middle layers is adopted. But
>> that should not be a problem.
>>
>> The benefit would be that those middle layers that can cope with
>> LEAVE_SUSPENDED as of today don't need to change.
>
> I'm not sure if that's the case.
>
> The middle layer has to evaluate dev_pm_may_skip_resume() in
> ->resume_noirq() to check if the device can be left in suspend, as it
> cannot determine that in ->suspend_noirq() yet.
Right. Okay, let's stick with the chosen method.
Kind regards
Uffe
next prev parent reply other threads:[~2017-11-17 15:57 UTC|newest]
Thread overview: 135+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-16 1:12 [PATCH 0/12] PM / sleep: Driver flags for system suspend/resume Rafael J. Wysocki
2017-10-16 1:29 ` [PATCH 01/12] PM / core: Add NEVER_SKIP and SMART_PREPARE driver flags Rafael J. Wysocki
2017-10-16 5:34 ` Lukas Wunner
2017-10-16 22:03 ` Rafael J. Wysocki
2017-10-16 6:28 ` Greg Kroah-Hartman
2017-10-16 22:05 ` Rafael J. Wysocki
2017-10-17 7:15 ` Greg Kroah-Hartman
2017-10-17 15:26 ` Rafael J. Wysocki
2017-10-18 6:56 ` Greg Kroah-Hartman
2017-10-16 6:31 ` Greg Kroah-Hartman
2017-10-16 22:07 ` Rafael J. Wysocki
2017-10-17 13:26 ` Greg Kroah-Hartman
2017-10-16 20:16 ` Alan Stern
2017-10-16 22:11 ` Rafael J. Wysocki
2017-10-18 23:17 ` [Update][PATCH v2 " Rafael J. Wysocki
2017-10-19 7:33 ` Greg Kroah-Hartman
2017-10-20 11:11 ` Rafael J. Wysocki
2017-10-20 11:35 ` Greg Kroah-Hartman
2017-10-20 11:28 ` Rafael J. Wysocki
2017-10-23 16:37 ` Ulf Hansson
2017-10-23 20:41 ` Rafael J. Wysocki
2017-10-16 1:29 ` [PATCH 02/12] PCI / PM: Use the NEVER_SKIP driver flag Rafael J. Wysocki
2017-10-23 16:40 ` Ulf Hansson
2017-10-16 1:29 ` [PATCH 03/12] PM: i2c-designware-platdrv: Use DPM_FLAG_SMART_PREPARE Rafael J. Wysocki
2017-10-23 16:57 ` Ulf Hansson
2017-10-16 1:29 ` [PATCH 04/12] PM / core: Add SMART_SUSPEND driver flag Rafael J. Wysocki
2017-10-23 19:01 ` Ulf Hansson
2017-10-24 5:22 ` Ulf Hansson
2017-10-24 8:55 ` Rafael J. Wysocki
2017-10-16 1:29 ` [PATCH 05/12] PCI / PM: Drop unnecessary invocations of pcibios_pm_ops callbacks Rafael J. Wysocki
2017-10-23 19:06 ` Ulf Hansson
2017-10-16 1:29 ` [PATCH 06/12] PCI / PM: Take SMART_SUSPEND driver flag into account Rafael J. Wysocki
2017-10-16 1:29 ` [PATCH 07/12] ACPI / LPSS: Consolidate runtime PM and system sleep handling Rafael J. Wysocki
2017-10-23 19:09 ` Ulf Hansson
2017-10-16 1:30 ` [PATCH 08/12] ACPI / PM: Take SMART_SUSPEND driver flag into account Rafael J. Wysocki
2017-10-16 1:30 ` [PATCH 09/12] PM / mfd: intel-lpss: Use DPM_FLAG_SMART_SUSPEND Rafael J. Wysocki
2017-10-31 15:09 ` Lee Jones
2017-10-31 16:28 ` Rafael J. Wysocki
2017-11-01 9:28 ` Lee Jones
2017-11-01 20:26 ` Rafael J. Wysocki
2017-11-08 11:08 ` Lee Jones
2017-10-16 1:30 ` [PATCH 10/12] PM / core: Add LEAVE_SUSPENDED driver flag Rafael J. Wysocki
2017-10-23 19:38 ` Ulf Hansson
2017-10-16 1:31 ` [PATCH 11/12] PM: i2c-designware-platdrv: Optimize power management Rafael J. Wysocki
2017-10-26 20:41 ` Wolfram Sang
2017-10-26 21:14 ` Rafael J. Wysocki
2017-10-16 1:32 ` [PATCH 12/12] PM / core: Add AVOID_RPM driver flag Rafael J. Wysocki
2017-10-17 15:33 ` Andy Shevchenko
2017-10-17 15:59 ` Rafael J. Wysocki
2017-10-17 16:25 ` Andy Shevchenko
2017-10-16 7:08 ` [PATCH 0/12] PM / sleep: Driver flags for system suspend/resume Greg Kroah-Hartman
2017-10-16 21:50 ` Rafael J. Wysocki
2017-10-17 8:36 ` Ulf Hansson
2017-10-17 15:25 ` Rafael J. Wysocki
2017-10-17 19:41 ` Ulf Hansson
2017-10-17 20:12 ` Alan Stern
2017-10-17 23:07 ` Rafael J. Wysocki
2017-10-18 0:39 ` Rafael J. Wysocki
2017-10-18 10:24 ` Rafael J. Wysocki
2017-10-18 12:34 ` Ulf Hansson
2017-10-18 21:54 ` Rafael J. Wysocki
2017-10-18 11:57 ` Ulf Hansson
2017-10-18 13:00 ` Rafael J. Wysocki
2017-10-18 14:11 ` Ulf Hansson
2017-10-18 19:45 ` Grygorii Strashko
2017-10-18 21:48 ` Rafael J. Wysocki
2017-10-19 8:33 ` Ulf Hansson
2017-10-19 17:21 ` Grygorii Strashko
2017-10-19 18:04 ` Ulf Hansson
2017-10-19 18:11 ` Ulf Hansson
2017-10-19 21:31 ` Grygorii Strashko
2017-10-20 6:05 ` Ulf Hansson
2017-10-18 22:12 ` Rafael J. Wysocki
2017-10-19 12:21 ` Ulf Hansson
2017-10-19 18:01 ` Ulf Hansson
2017-10-20 1:19 ` Rafael J. Wysocki
2017-10-20 5:57 ` Ulf Hansson
2017-10-20 20:46 ` Bjorn Helgaas
2017-10-21 1:04 ` Rafael J. Wysocki
2017-10-27 22:11 ` [PATCH v2 0/6] PM / sleep: Driver flags for system suspend/resume (part 1) Rafael J. Wysocki
2017-10-27 22:17 ` [PATCH v2 1/6] PM / core: Add NEVER_SKIP and SMART_PREPARE driver flags Rafael J. Wysocki
2017-11-06 8:07 ` Ulf Hansson
2017-10-27 22:19 ` [PATCH v2 2/6] PCI / PM: Use the NEVER_SKIP driver flag Rafael J. Wysocki
2017-10-27 22:22 ` [PATCH v2 3/6] PM / core: Add SMART_SUSPEND " Rafael J. Wysocki
2017-11-06 8:09 ` Ulf Hansson
2017-11-06 11:23 ` Rafael J. Wysocki
2017-10-27 22:23 ` [PATCH v2 4/6] PCI / PM: Drop unnecessary invocations of pcibios_pm_ops callbacks Rafael J. Wysocki
2017-10-27 22:27 ` [PATCH v2 5/6] PCI / PM: Take SMART_SUSPEND driver flag into account Rafael J. Wysocki
2017-10-31 22:48 ` Bjorn Helgaas
2017-10-27 22:30 ` [PATCH v2 6/6] ACPI " Rafael J. Wysocki
2017-11-08 0:41 ` [PATCH v2 0/6] PM / sleep: Driver flags for system suspend/resume (part 2) Rafael J. Wysocki
2017-11-08 13:25 ` [PATCH v2 1/6] PM / core: Add LEAVE_SUSPENDED driver flag Rafael J. Wysocki
2017-11-10 9:09 ` Ulf Hansson
2017-11-10 23:45 ` Rafael J. Wysocki
2017-11-11 0:41 ` Rafael J. Wysocki
2017-11-11 1:36 ` Rafael J. Wysocki
2017-11-14 16:07 ` Ulf Hansson
2017-11-15 1:48 ` Rafael J. Wysocki
2017-11-16 10:18 ` Ulf Hansson
2017-11-08 13:28 ` [PATCH v2 2/6] PCI / PM: Support for " Rafael J. Wysocki
2017-11-08 20:38 ` Bjorn Helgaas
2017-11-08 21:09 ` Rafael J. Wysocki
2017-11-08 13:34 ` [PATCH v2 3/6] ACPI / PM: Support for LEAVE_SUSPENDED driver flag in ACPI PM domain Rafael J. Wysocki
2017-11-08 13:37 ` [PATCH v2 4/6] PM / core: Add helpers for subsystem callback selection Rafael J. Wysocki
2017-11-08 13:38 ` [PATCH v2 5/6] PM / core: Direct handling of DPM_FLAG_LEAVE_SUSPENDED Rafael J. Wysocki
2017-11-08 13:39 ` [PATCH v2 6/6] PM / core: DPM_FLAG_SMART_SUSPEND optimization Rafael J. Wysocki
2017-11-12 0:34 ` [PATCH v3 0/6] PM / sleep: Driver flags for system suspend/resume (part 2) Rafael J. Wysocki
2017-11-12 0:37 ` [PATCH v3 1/6] PM / core: Add LEAVE_SUSPENDED driver flag Rafael J. Wysocki
2017-11-16 15:10 ` Ulf Hansson
2017-11-16 23:07 ` Rafael J. Wysocki
2017-11-17 6:11 ` Ulf Hansson
2017-11-17 13:18 ` Rafael J. Wysocki
2017-11-17 13:49 ` Ulf Hansson
2017-11-17 14:31 ` Rafael J. Wysocki
2017-11-17 15:57 ` Ulf Hansson [this message]
2017-11-17 12:45 ` Rafael J. Wysocki
2017-11-12 0:40 ` [PATCH v3 2/6] PCI / PM: Support for " Rafael J. Wysocki
2017-11-12 0:40 ` [PATCH v3 3/6] ACPI / PM: Support for LEAVE_SUSPENDED driver flag in ACPI PM domain Rafael J. Wysocki
2017-11-12 0:42 ` [PATCH v3 4/6] PM / core: Add helpers for subsystem callback selection Rafael J. Wysocki
2017-11-15 7:43 ` Ulf Hansson
2017-11-15 17:55 ` Rafael J. Wysocki
2017-11-12 0:43 ` [PATCH v3 5/6] PM / core: Direct handling of DPM_FLAG_LEAVE_SUSPENDED Rafael J. Wysocki
2017-11-12 0:44 ` [PATCH v3 6/6] PM / core: DPM_FLAG_SMART_SUSPEND optimization Rafael J. Wysocki
2017-11-18 14:27 ` [PATCH v4 0/6] PM / sleep: Driver flags for system suspend/resume (part 2) Rafael J. Wysocki
2017-11-18 14:31 ` [PATCH v4 1/6] PM / core: Add LEAVE_SUSPENDED driver flag Rafael J. Wysocki
2017-11-20 12:25 ` Ulf Hansson
2017-11-21 0:16 ` Rafael J. Wysocki
2017-11-18 14:33 ` [PATCH v4 2/6] PCI / PM: Support for " Rafael J. Wysocki
2017-11-18 14:35 ` [PATCH v4 3/6] ACPI / PM: Support for LEAVE_SUSPENDED driver flag in ACPI PM domain Rafael J. Wysocki
2017-11-18 14:37 ` [PATCH v4 4/6] PM / core: Add helpers for subsystem callback selection Rafael J. Wysocki
2017-11-18 14:41 ` [PATCH v4 5/6] PM / core: Direct handling of DPM_FLAG_LEAVE_SUSPENDED Rafael J. Wysocki
2017-11-20 13:42 ` Ulf Hansson
2017-11-22 1:10 ` Rafael J. Wysocki
2017-11-22 1:28 ` Rafael J. Wysocki
2017-11-18 14:44 ` [PATCH v4 6/6] PM / core: DPM_FLAG_SMART_SUSPEND optimization Rafael J. Wysocki
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