Re: [RFC PATCH v3 3/4] block: implement runtime pm strategy

[Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>]

On Wed, 23 May 2012, Lin Ming wrote:

> >> + � � � � � � /* Only PM request is allowed to go if the queue is suspended */
> >> + � � � � � � if (q->rpm_status != RPM_ACTIVE && !(rq->cmd_flags & REQ_PM)) {
> >> + � � � � � � � � � � rq = NULL;
> >> + � � � � � � � � � � break;
> >> + � � � � � � }
> >
> > Not even PM requests should be allowed to go if the status is
> > RPM_SUSPENDED.
> 
> PM requests are used to wake up the device.
> If they are not allowed to go, then how to wake up the device?

When blk_pre_runtime_resume runs, the status is changed to
RPM_RESUMING.  _Then_ PM requests are allowed to go.  Not before.

Alan Stern

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