Re: [PATCH 0/3] ata port runtime power management support

[Lin Ming <ming.m.lin@intel.com>]

On Wed, 2011-11-02 at 23:17 +0800, Tejun Heo wrote:
> Hello,
> 
> On Wed, Nov 02, 2011 at 02:21:37PM +0800, Lin Ming wrote:
> > These 3 patches add ata port runtime pm support, which is done through scsi layer.
> > scsi host runtime pm mechanism is already there(scsi_pm.c).
> > These patches add hooks for ata port.
> > 
> > Lin Ming (3):
> >       scsi: fix potential dead lock for host runtime pm
> >       scsi: add hooks for host runtime power management
> >       ata: implement ata port runtime pm hooks
> 
> Hmmm.... Some questions.
> 
> * How much does this add on top of hardware timed auto spindown and
>   dynamic link power management?

Sorry, I don't understand this question.
What do you mean?

> 
> * Do the added benefits justify yet another runtime powersaving
>   mechanism?

There will be ACPI firmware which supports ata port runtime D3Cold.
To enable ata port runtime PM is the first step.

> 
> * Any way we can tie the other stuff with overall runtime PM?

What's the other stuff?
Do you mean tie disk/link/port/controller stuff with overall runtime PM?

I'm not sure for now. Need to think about it more.