Re: [RFC PATCH v3 0/4]: block layer runtime pm

[Alan Stern]

On Wed, 23 May 2012, Lin Ming wrote:

> On Wed, May 23, 2012 at 11:03 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> > On Wed, 23 May 2012, Lin Ming wrote:
> >
> >> Another thing need to check is if system suspend/resume works.
> >
> > Right!  Although I would hope that your work doesn't interfere at all
> > with system sleep, since it touches only the runtime PM pathways.
> 
> sd_sync_cache and sd_start_stop_device are changed with REQ_PM set.
> And they are called for system suspend too.
> 
> So it probably will have problem.

People have already run into problems where system suspend 
occurred at a time when a SCSI device was already runtime suspended.  
That's why scsi_bus_suspend_common() includes an appropriate check.

Alan Stern

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