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From: Alan Stern <stern@rowland.harvard.edu>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Ming Lei <tom.leiming@gmail.com>, <linux-pci@vger.kernel.org>,
	USB list <linux-usb@vger.kernel.org>,
	Linux PM list <linux-pm@vger.kernel.org>
Subject: Re: Do we need asynchronous pm_runtime_get()? (was: Re: bisected regression ...)
Date: Sat, 4 Aug 2012 16:48:25 -0400 (EDT)	[thread overview]
Message-ID: <Pine.LNX.4.44L0.1208041644240.23711-100000@netrider.rowland.org> (raw)
In-Reply-To: <201208042248.24957.rjw@sisk.pl>

On Sat, 4 Aug 2012, Rafael J. Wysocki wrote:

> > That wasn't what he meant.  What if the code needs to run in the _same_
> > context as the caller?  For example, with a spinlock held.
> 
> I see.  I think it wouldn't be unreasonable to require that func should take
> all of the necessary locks by itself.

But then if func was called directly, because the device was at full
power, it would deadlock trying to acquire a lock the caller already
holds.

> However, I believe that if func is going to be called through the workqueue,
> the usage counter should be incremented before the preceding resume and
> decremented after func returns by the workqueue thread.

Okay.

> > func would need to know whether it should acquire the lock, which means it
> > needs to know whether it was called directly or through the workqueue.
> > 
> > I suppose we could pass it an extra argument with this information...  
> > but that's a little ugly.
> 
> I agree.  I'd prefer to avoid that, if possible.

Do you have any better suggestions?

Alan Stern


  reply	other threads:[~2012-08-04 20:48 UTC|newest]

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <Pine.LNX.4.44L0.1207241312050.1164-100000@iolanthe.rowland.org>
     [not found] ` <87r4s0opck.fsf@nemi.mork.no>
2012-07-25  4:08   ` bisected regression, v3.5 -> next-20120724: PCI PM causes USB hotplug failure Bjørn Mork
2012-07-25  4:34     ` Huang Ying
2012-07-25  9:58       ` Bjørn Mork
2012-07-25 13:30         ` huang ying
2012-07-25 13:58           ` Bjørn Mork
2012-07-25 18:56             ` Rafael J. Wysocki
2012-07-25 20:02             ` Rafael J. Wysocki
2012-07-25 22:36               ` Bjørn Mork
2012-07-26  2:38                 ` Huang Ying
2012-07-26  2:38               ` Huang Ying
2012-07-26  8:54             ` Huang Ying
2012-07-26 10:35               ` Bjørn Mork
2012-07-26 11:02                 ` Bjørn Mork
2012-07-26 12:04                   ` Bjørn Mork
2012-07-26 15:03                 ` Alan Stern
2012-07-26 16:24                   ` Bjørn Mork
2012-07-27  5:35                 ` Huang Ying
2012-07-27  9:11                   ` Bjørn Mork
2012-07-30  3:15                     ` Huang Ying
2012-07-30  8:08                       ` Bjørn Mork
2012-07-30 13:31                         ` huang ying
2012-07-30 16:57                           ` Bjørn Mork
2012-07-31  0:22                             ` Huang Ying
2012-07-30 14:19                       ` Alan Stern
2012-07-31  0:24                         ` Huang Ying
2012-07-31  3:18                         ` Huang Ying
2012-07-31 17:07                           ` Alan Stern
2012-07-27 15:03                   ` Alan Stern
2012-07-27 19:11                     ` Rafael J. Wysocki
2012-07-27 19:39                       ` Alan Stern
2012-07-27 19:54                         ` Rafael J. Wysocki
2012-07-28 16:12                           ` Alan Stern
2012-07-28 20:26                             ` Rafael J. Wysocki
2012-07-28 21:12                               ` Alan Stern
2012-07-29 13:55                                 ` Rafael J. Wysocki
2012-07-29 14:55                                   ` Alan Stern
2012-07-29 19:18                                     ` Rafael J. Wysocki
2012-07-31 20:31                                       ` Do we need asynchronous pm_runtime_get()? (was: Re: bisected regression ...) Rafael J. Wysocki
2012-07-31 21:05                                         ` Alan Stern
2012-07-31 21:34                                           ` Rafael J. Wysocki
2012-07-31 21:49                                             ` Rafael J. Wysocki
2012-08-01 14:36                                             ` Alan Stern
2012-08-01 21:24                                               ` Rafael J. Wysocki
2012-08-02 20:16                                                 ` Alan Stern
2012-08-02 21:26                                                   ` Rafael J. Wysocki
2012-08-03  2:20                                                     ` Alan Stern
2012-08-03  3:37                                                       ` Ming Lei
2012-08-03 14:28                                                         ` Alan Stern
2012-08-04 19:47                                                         ` Rafael J. Wysocki
2012-08-04 20:25                                                           ` Alan Stern
2012-08-04 20:48                                                             ` Rafael J. Wysocki
2012-08-04 20:48                                                               ` Alan Stern [this message]
2012-08-04 21:15                                                                 ` Rafael J. Wysocki
2012-08-04 22:13                                                                   ` Alan Stern
2012-08-05 15:26                                                                     ` Rafael J. Wysocki
2012-08-06 13:30                                                                       ` Ming Lei
2012-08-06 14:47                                                                         ` Alan Stern
2012-08-07  1:35                                                                           ` Ming Lei
2012-08-07 11:23                                                                             ` Rafael J. Wysocki
2012-08-07 15:14                                                                               ` Ming Lei
2012-08-07 15:42                                                                                 ` Alan Stern
2012-08-07 16:30                                                                                   ` Ming Lei
2012-08-07 20:57                                                                                     ` Rafael J. Wysocki
2012-08-07 20:45                                                                                 ` Rafael J. Wysocki
2012-08-08  2:02                                                                                   ` Ming Lei
2012-08-08 18:42                                                                                     ` Alan Stern
2012-08-08 20:16                                                                                       ` Rafael J. Wysocki
2012-08-09  5:55                                                                                         ` Ming Lei
2012-08-09 10:46                                                                                           ` Rafael J. Wysocki
2012-08-09 10:55                                                                                             ` Ming Lei
2012-08-09 19:41                                                                                               ` Rafael J. Wysocki
2012-08-10  3:19                                                                                                 ` Ming Lei
2012-08-10 20:29                                                                                                   ` Rafael J. Wysocki
2012-08-08 22:27                                                                                     ` Rafael J. Wysocki
2012-08-06 15:48                                                                       ` Alan Stern
2012-08-06 20:30                                                                         ` Rafael J. Wysocki
2012-08-07 12:28                                                                           ` Rafael J. Wysocki
2012-08-07 17:15                                                                             ` Alan Stern
2012-08-07 21:31                                                                               ` Rafael J. Wysocki
2012-08-03 14:05                                                       ` Alan Stern
2012-08-04 20:08                                                         ` Rafael J. Wysocki
2012-08-04 20:42                                                           ` Alan Stern
2012-08-04 20:59                                                             ` Rafael J. Wysocki
2012-08-04 19:35                                                       ` Rafael J. Wysocki
2012-07-29 20:12                                     ` bisected regression, v3.5 -> next-20120724: PCI PM causes USB hotplug failure Jassi Brar
2012-07-29 21:44                                       ` Alan Stern
2012-07-25 19:51           ` [PATCH] PCI / PM: Fix messages printed by acpi_pci_set_power_state() Rafael J. Wysocki
2012-07-25 20:02             ` Alan Stern
2012-07-25 20:48               ` [PATCH][update] " Rafael J. Wysocki

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