From: Alan Stern <stern@rowland.harvard.edu>
To: Phillip Susi <psusi@ubuntu.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
Todd E Brandt <todd.e.brandt@linux.intel.com>,
Aaron Lu <aaron.lu@intel.com>, Tejun Heo <tj@kernel.org>,
SCSI development list <linux-scsi@vger.kernel.org>
Subject: Re: Disk spin-up optimization during system resume
Date: Tue, 21 Jan 2014 11:03:20 -0500 (EST) [thread overview]
Message-ID: <Pine.LNX.4.44L0.1401211049160.1272-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <52DE860C.6010502@ubuntu.com>
On Tue, 21 Jan 2014, Phillip Susi wrote:
> On 1/21/2014 5:12 AM, Dan Williams wrote:
> > The need is to avoid tying rpm and dpm ops together in surprising
> > new ways that require userspace to change if it wants to keep the
> > default behavior of hiding resume latency as much as possible. A
> > lazy_resume knob vs changing the default let's the few setups that
> > care set the power-up in standby mode. It should also "perform"
> > better given it does not require the disk to be runtime suspended
> > prior to system suspend, it will unconditionally resume on demand.
>
> The more I think about it the more I agree that the new knob is
> needed. If the user wants runtime pm but without the lazy system
> resume, switching off runtime pm prior to suspend would needlessly
> force the disk to spin up if it is already in standby, then right back
> down again. At least, that's how rpm is currently implemented, which
> is something else I found odd about it. Why can't you disable auto
> suspend, but still be able to manually suspend or leave an already
> suspended device asleep?
The user is in charge of enabling or disabling runtime PM. But the
kernel chooses whether or not runtime PM will use autosuspend -- the
user doesn't get to decide that. It is determined by how the driver is
written.
Thus, if a device's driver chooses to use autosuspend, the only way the
user can prevent the device from going into runtime suspend is by
disabling it for runtime PM altogether (which means waking up the
device if it is already suspended).
However, there is a compromise. The user gets to select the
autosuspend delay. If that delay is set to a very large value, it will
effectively prevent autosuspends from occurring, without causing an
already-suspended device to resume right away. (On the other hand, it
would not prevent a lazy resume.)
Alan Stern
next prev parent reply other threads:[~2014-01-21 16:03 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
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 [this message]
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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