Re: [PATCH] PM: Acquire device locks on suspend (rev. 3)

[Alan Stern]

On Fri, 11 Jan 2008, Rafael J. Wysocki wrote:

> Hi,
> 
> The patch below is intended as a replacement for
> gregkh-driver-pm-acquire-device-locks-prior-to-suspending.patch that deadlocked
> suspend and hibernation on some systems. Â The present patch contains some
> safeguards against deadlocks in the relevant cases and a mechanism to print
> warnings if a deadlock is probable.
> 
> Greetings,
> Rafael
> 
> ---
> From: Rafael J. Wysocki <rjw@xxxxxxx>, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
> 
> This patch reorganizes the way suspend and resume notifications are
> sent to drivers.  The major changes are that now the PM core acquires
> every device semaphore before calling the methods, and calls to
> device_add() during suspends will fail, while calls to device_del()
> during suspends will block.
> 
> It also provides a way to safely remove a suspended device with the
> help of the PM core, by using the device_pm_schedule_removal() callback
> introduced specifically for this purpose, and updates two drivers (msr
> and cpuid) that need to use it.
> 
> Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>

Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>

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