From: Alan Stern <stern@rowland.harvard.edu>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>,
Ohad Ben-Cohen <ohad@wizery.com>,
linux-mmc@vger.kernel.org, Magnus Damm <damm@opensource.se>,
Simon Horman <horms@verge.net.au>,
Linux PM mailing list <linux-pm@lists.linux-foundation.org>
Subject: Re: [PATCH/RFC] MMC: remove unbalanced pm_runtime_suspend()
Date: Wed, 20 Apr 2011 17:16:11 -0400 (EDT) [thread overview]
Message-ID: <Pine.LNX.4.44L0.1104201710450.1686-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <201104202206.14240.rjw@sisk.pl>
On Wed, 20 Apr 2011, Rafael J. Wysocki wrote:
> On Wednesday, April 20, 2011, Alan Stern wrote:
> > On Wed, 20 Apr 2011, Guennadi Liakhovetski wrote:
> ...
> > Ah, now I see the problem. It looks like we did not give sufficient
> > thought to the case where a device starts off (and therefore should
> > finish up) in a powered-down state. Calling pm_runtime_put_sync()
> > after unbinding the device driver seems a little futile -- with no
> > driver, the subsystem may not be able to power-down the device!
> >
> > Rafael, how do you think we should handle this? Get rid of the
> > pm_runtime_get_no_resume() and pm_runtime_put_sync() calls in
> > dd.c:__device_release_driver()?
>
> I think we need pm_runtime_barrier() in there. Otherwise we risk
> removing the driver while there's a runtime PM request pending.
>
> But we can move the pm_runtime_put_sync() before driver_sysfs_remove().
What happens if another runtime PM request is queued between the
put_sync() and the remove callback? We may need a safe way to prevent
async runtime PM requests while still allowing synchronous requests.
Alan Stern
next prev parent reply other threads:[~2011-04-20 21:16 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-19 10:46 [PATCH/RFC] MMC: remove unbalanced pm_runtime_suspend() Guennadi Liakhovetski
2011-04-19 12:44 ` Ohad Ben-Cohen
2011-04-19 13:23 ` Guennadi Liakhovetski
2011-04-19 14:16 ` Ohad Ben-Cohen
2011-04-19 14:26 ` Alan Stern
2011-04-19 22:59 ` Guennadi Liakhovetski
2011-04-20 14:22 ` Alan Stern
2011-04-20 14:50 ` Guennadi Liakhovetski
2011-04-20 15:12 ` Alan Stern
2011-04-20 20:06 ` Rafael J. Wysocki
2011-04-20 21:16 ` Alan Stern [this message]
2011-04-20 21:44 ` Rafael J. Wysocki
2011-04-21 13:58 ` Alan Stern
2011-04-21 18:00 ` Rafael J. Wysocki
2011-04-21 18:36 ` Alan Stern
2011-04-21 20:05 ` Rafael J. Wysocki
2011-04-21 21:48 ` Alan Stern
2011-04-21 22:06 ` Rafael J. Wysocki
2011-04-22 15:20 ` Alan Stern
2011-04-22 20:22 ` Rafael J. Wysocki
2011-04-22 20:25 ` Rafael J. Wysocki
2011-04-22 21:20 ` Alan Stern
2011-04-22 22:11 ` Rafael J. Wysocki
2011-04-25 10:29 ` [linux-pm] " Rafael J. Wysocki
2011-04-26 10:44 ` Guennadi Liakhovetski
2011-04-26 11:51 ` Rafael J. Wysocki
2011-04-28 22:12 ` Rafael J. Wysocki
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