On Fri, Dec 05, 2014 at 02:18:40PM -0500, Alan Stern wrote:
> On Fri, 5 Dec 2014, Chuansheng Liu wrote:
>
> > Some history from
> > commit e6b7e41cdd8c ("ata: Disabling the async PM for JMicron chip 363/361")
> > ==
> > Since v3.15, the PM feature of async noirq
> > commit 76569faa62c4 ("PM / sleep: Asynchronous threads for resume_noirq") is introduced.
> >
> > Then Jay hit one system resuming issue that one of the JMicron controller
> > can not be powered up successfully.
> >
> > His device tree is like below:
> > +-1c.4-[02]--+-00.0 JMicron Technology Corp. JMB363 SATA/IDE Controller
> > | \-00.1 JMicron Technology Corp. JMB363 SATA/IDE Controller
> >
> > After investigation, we found the the Micron chip 363 included
> > one SATA controller(0000:02:00.0) and one PATA controller(0000:02:00.1),
> > these two controllers do not have parent-children relationship,
> > but the PATA controller only can be powered on after the SATA controller
> > has finished the powering on.
> >
> > If we enabled the async noirq(), then the below error is hit during noirq
> > phase:
> > pata_jmicron 0000:02:00.1: Refused to change power state, currently in D3
> > Here for JMicron chip 363/361, we need forcedly to disable the async method.
>
> You know, this is exactly why device_pm_wait_for_dev() exists -- so
> that asynchronous power-management operations can wait for other
> devices even when there's no parent-child relation.
>
> You should try to use device_pm_wait_for_dev() instead of disabling
> async suspend/resume.
Dropping this patch for now, waiting for a response to Alan's suggestion.
Bjorn
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