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From: Alan Stern <stern@rowland.harvard.edu>
To: Phillip Susi <psusi@ubuntu.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Aaron Lu <aaron.lu@intel.com>,
	Linux-pm mailing list <linux-pm@vger.kernel.org>
Subject: Re: Allow runtime suspend during system resume
Date: Sat, 11 Jan 2014 17:50:40 -0500 (EST)	[thread overview]
Message-ID: <Pine.LNX.4.44L0.1401111735050.16586-100000@netrider.rowland.org> (raw)
In-Reply-To: <52D0A79E.6080905@ubuntu.com>

On Fri, 10 Jan 2014, Phillip Susi wrote:

> On 01/10/2014 06:02 PM, Rafael J. Wysocki wrote:
> > So, my opinion is that the runtime PM internal information should
> > be made reflect the actual (and/or desirable) state of things
> > before it is re-enabled, which practically means in the
> > .resume_noirq()/.resume_early() time frame.
> > 
> > Doing it after that might actually work, but is questionable from
> > the overall consistency perspective (it basically would mean that
> > we ran with wrong runtime PM data for a while after we'd re-enabled
> > it and before it got adjusted, so we shouldn't have re-enabled it
> > in the first place).
> 
> But we don't want to block the system resume path for too long while
> we figure out what the correct state is.

We won't.  The resume_early routine will set the status to RPM_ACTIVE 
or RPM_SUSPENDED, according to the result from 
pm_runtime_usage_during_sleep.  It will also do a pm_runtime_get_sync 
on the disk's parent, to prevent the parent from going into runtime 
suspend before the async routine can run.

Then the async routine will do the following:

	If the status is RPM_ACTIVE, spin up the disk.

	Else (the status is RPM_SUSPENDED) check whether the disk has
	spun up by itself.  If it has, or if you can't tell, call 
	pm_runtime_resume to set the status correctly and do an 
	explicit spin-up.

	Call pm_runtime_put_sync on the parent.

I think this will give the desired result.  But there is one potential
problem: If the disk has a child device (such as a partition) and the
child's driver needs to do I/O as part of its resume routine, the I/O
is likely to hang if the disk is runtime suspended.  However, I don't
know of any child devices like this.

Alan Stern


  reply	other threads:[~2014-01-11 22:50 UTC|newest]

Thread overview: 165+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-17 19:33 [PATCH/RESEND v2 0/2] SATA disk resume time optimization Todd E Brandt
2013-11-07  1:53 ` Phillip Susi
2013-11-07  1:57   ` [PATCH 1/3] sd: don't bother spinning up disks on resume Phillip Susi
2013-11-07 18:21     ` Douglas Gilbert
2013-11-07 21:16       ` Phillip Susi
2013-11-16 18:20         ` James Bottomley
2013-11-17  3:50           ` Phillip Susi
2013-11-17  6:43             ` James Bottomley
2013-11-17 16:15               ` Phillip Susi
2013-11-17 23:54                 ` Douglas Gilbert
2013-11-18  1:06                   ` Phillip Susi
2013-11-18 15:54                     ` Phillip Susi
2013-11-20 14:23                       ` Mark Lord
2013-11-20 14:48                         ` Phillip Susi
2013-11-28  1:39                           ` Phillip Susi
2013-11-18  0:09                 ` James Bottomley
2013-11-18  1:11                   ` Phillip Susi
2013-11-16  5:23       ` Mark Lord
2013-11-16 14:52         ` Phillip Susi
2013-11-07  1:57   ` [PATCH 2/3] libata: resume in the background Phillip Susi
2013-11-07  1:57   ` [PATCH 3/3] libata: don't start disks on resume Phillip Susi
2013-11-09  1:20   ` [PATCH/RESEND v2 0/2] SATA disk resume time optimization Todd E Brandt
2013-11-09 20:59     ` Phillip Susi
2013-11-09 21:03       ` [PATCH 0/6] Let sleeping disks lie Phillip Susi
2013-12-16 23:30         ` Phillip Susi
2013-12-16 23:30           ` [PATCH 1/6] libata: use sleep instead of standby command Phillip Susi
2013-12-16 23:30           ` [PATCH 2/6] libata: avoid waking disk for several commands Phillip Susi
2013-12-16 23:30           ` [PATCH 3/6] libata: resume in the background Phillip Susi
2014-01-10 22:26             ` Dan Williams
2014-01-11  2:25               ` Phillip Susi
2014-01-11  3:11                 ` Dan Williams
2013-12-16 23:30           ` [PATCH 4/6] libata: don't start disks on resume Phillip Susi
2013-12-16 23:30           ` [PATCH 5/6] sd: don't start disks on system resume Phillip Susi
2013-12-17  6:43             ` James Bottomley
2013-12-17 15:01               ` Phillip Susi
2013-12-17 17:48                 ` James Bottomley
2013-12-17 18:30                   ` Phillip Susi
2013-12-16 23:30           ` [PATCH 6/6] libata: return power status in REQUEST SENSE command Phillip Susi
2013-12-17 18:02             ` Sergei Shtylyov
2013-12-17 18:35               ` Phillip Susi
2014-01-06  2:14           ` REQ_PM vs REQ_TYPE_PM_RESUME Phillip Susi
2014-01-06  7:36             ` Sujit Reddy Thumma
2014-01-06  9:15               ` Aaron Lu
2014-01-06 14:40                 ` Phillip Susi
2014-01-06 15:38                   ` Alan Stern
2014-01-07  2:44                     ` Phillip Susi
2014-01-07 15:20                       ` Alan Stern
2014-01-07 15:40                         ` Phillip Susi
2014-01-07 15:56                           ` Alan Stern
2014-01-09 18:29                           ` Douglas Gilbert
2014-01-09 19:20                             ` Phillip Susi
2014-01-10  5:23                               ` Douglas Gilbert
2014-01-10 14:29                                 ` Phillip Susi
2014-01-07  7:49                   ` Aaron Lu
2014-01-07 14:50                     ` Phillip Susi
2014-01-08  1:03                       ` Aaron Lu
2014-01-08  1:16                         ` Phillip Susi
2014-01-08  1:32                           ` Aaron Lu
2014-01-08  1:53                             ` Phillip Susi
2014-01-08  2:11                               ` Aaron Lu
2014-01-08  2:19                                 ` Phillip Susi
2014-01-08  2:36                                   ` Aaron Lu
2014-01-08  5:24                                     ` Phillip Susi
2014-01-08  7:00                                       ` Aaron Lu
2014-01-08 19:30                                         ` Phillip Susi
2014-01-07 15:25                     ` Alan Stern
2014-01-07 15:43                       ` Phillip Susi
2014-01-07 16:08                         ` Alan Stern
2014-01-07 16:37                           ` Phillip Susi
2014-01-07 18:05                             ` Alan Stern
2014-01-07 18:43                               ` Phillip Susi
2014-01-07 19:18                                 ` Alan Stern
2014-01-07 23:47                                   ` Phillip Susi
2014-01-08 17:46                                     ` Alan Stern
2014-01-08 18:31                                       ` Alan Stern
2014-01-08 20:44                                         ` Allow runtime suspend during system resume Alan Stern
2014-01-08 21:17                                           ` Phillip Susi
2014-01-08 21:34                                             ` Alan Stern
2014-01-09 10:14                                               ` Ulf Hansson
2014-01-09 15:41                                                 ` Alan Stern
2014-01-08 22:55                                           ` Rafael J. Wysocki
2014-01-08 23:24                                             ` Alan Stern
2014-01-09  0:05                                               ` Rafael J. Wysocki
2014-01-09 15:32                                                 ` Alan Stern
2014-01-09 15:50                                                   ` Phillip Susi
2014-01-09 16:08                                                     ` Alan Stern
2014-01-09 16:30                                                       ` Phillip Susi
2014-01-09 17:04                                                         ` Alan Stern
2014-01-10  1:25                                                   ` Rafael J. Wysocki
2014-01-10  1:55                                                     ` Phillip Susi
2014-01-10 13:35                                                       ` Rafael J. Wysocki
2014-01-10 14:46                                                         ` Phillip Susi
2014-01-10 15:25                                                     ` Alan Stern
2014-01-10 23:02                                                       ` Rafael J. Wysocki
2014-01-11  2:08                                                         ` Phillip Susi
2014-01-11 22:50                                                           ` Alan Stern [this message]
2014-01-12  1:50                                                             ` Phillip Susi
2014-01-11 22:34                                                         ` Alan Stern
2014-01-08 20:20                                       ` REQ_PM vs REQ_TYPE_PM_RESUME Phillip Susi
2014-01-08 21:21                                         ` Alan Stern
2014-01-08 21:50                                           ` Phillip Susi
2014-01-09  1:29                                           ` Aaron Lu
2014-01-09 12:17                                             ` Rafael J. Wysocki
2014-01-09 13:18                                               ` Rafael J. Wysocki
2014-01-09 15:40                                             ` Alan Stern
2014-01-09 15:53                                               ` Phillip Susi
2014-01-09 16:14                                                 ` Alan Stern
2014-01-09 16:34                                                   ` Phillip Susi
2014-01-09 17:06                                                     ` Alan Stern
2014-01-16 16:59                                                 ` Disk spin-up optimization during system resume Alan Stern
2014-01-16 18:04                                                   ` Todd E Brandt
2014-01-16 18:33                                                     ` Phillip Susi
2014-01-16 20:05                                                     ` Alan Stern
2014-01-16 22:04                                                       ` Todd E Brandt
2014-01-17 14:57                                                         ` Alan Stern
2014-01-17 19:31                                                           ` Dan Williams
2014-01-17 20:15                                                             ` Alan Stern
2014-01-17 20:24                                                               ` Tejun Heo
2014-01-17 20:55                                                                 ` Phillip Susi
2014-01-18 14:04                                                                   ` Tejun Heo
2014-01-18  1:36                                                                 ` Todd E Brandt
2014-01-18  1:41                                                                 ` Alan Stern
2014-01-18  2:15                                                                   ` Dan Williams
2014-01-18  2:33                                                                     ` Alan Stern
2014-01-18  3:24                                                                   ` Phillip Susi
2014-01-18 13:59                                                                   ` Tejun Heo
2014-01-17 20:49                                                             ` Phillip Susi
2014-01-17 22:17                                                               ` Dan Williams
2014-01-18  3:18                                                                 ` Phillip Susi
2014-01-18  4:09                                                                   ` Dan Williams
2014-01-18 14:08                                                                     ` Alan Stern
2014-01-21 10:12                                                                       ` Dan Williams
2014-01-21 14:37                                                                         ` Phillip Susi
2014-01-21 16:03                                                                           ` Alan Stern
2014-01-21 16:18                                                                             ` Phillip Susi
2014-01-21 16:49                                                                               ` Alan Stern
2014-01-21 15:44                                                                         ` Alan Stern
2014-01-21 16:18                                                                           ` Dan Williams
2014-01-21 16:55                                                                             ` Dan Williams
2014-01-20 12:38                                                                     ` CrashPlan Pro
2014-01-20 14:30                                                                       ` Phillip Susi
2014-01-18  1:24                                                           ` Todd E Brandt
2014-01-18  3:20                                                             ` Phillip Susi
2014-01-16 18:39                                                   ` Phillip Susi
2014-01-16 20:08                                                     ` Alan Stern
2014-01-17 10:16                                                   ` Oliver Neukum
2014-01-17 10:21                                                     ` Tejun Heo
2014-01-17 18:18                                                       ` Alan Stern
2014-01-17 18:39                                                       ` James Bottomley
2014-01-17 19:07                                                         ` Tejun Heo
2013-11-09 21:03       ` [PATCH 1/6] libata: use sleep instead of standby command Phillip Susi
2013-11-09 21:03       ` [PATCH 2/6] libata: avoid waking disk to check power Phillip Susi
2013-11-11 13:05         ` Sergei Shtylyov
2013-11-09 21:03       ` [PATCH 3/6] sd: don't bother spinning up disks on resume Phillip Susi
2013-11-11 13:08         ` Sergei Shtylyov
2013-11-11 14:28           ` Phillip Susi
2013-11-09 21:03       ` [PATCH 4/6] libata: resume in the background Phillip Susi
2013-11-11 13:10         ` Sergei Shtylyov
2013-11-09 21:03       ` [PATCH 5/6] libata: don't start disks on resume Phillip Susi
2013-11-09 21:03       ` [PATCH 6/6] libata: fake some more commands when drive is sleeping Phillip Susi
2013-11-11 16:59       ` [PATCH/RESEND v2 0/2] SATA disk resume time optimization Todd E Brandt
2013-11-11 17:08         ` Phillip Susi
2013-12-17 12:15           ` Tejun Heo
2013-12-17 14:24             ` Phillip Susi
2013-11-27 16:18 ` Phillip Susi

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