[lkml]   [2006]   [Sep]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: SATA powersave patches

> >Thanks... I got it to work (on 2 the old tree, I was not able to
> >forward-port it), but power savings were not too big (~0.1W, maybe).
> >
> >I'm getting huge (~1W) savings by powering down SATA controller, as in
> >ahci_pci_device_suspend().
> Yeah, it only turns off SATA PHY, so it doesn't result in huge saving.
> IIRC, it was somewhere around 5 percent on my notebook w/ static
> linksave mode (turning PHY off on empty port). But link powersaving
> introduces virtually no recognizable delay, so it's nice to have.

Yes, any powersavings without cost are a good idea.

> Can you check if there is any difference between [D/H]IPS and static?
> ICH6M on my notebook can't do DIPS/HIPS, so I couldn't compare them
> against static.

What is D/HIPS? I could not find anything relevant..

> >It would be great to be able to power SATA
> >controller down, then power it back up when it is needed... I tried
> >following hack, but could not get it to work. Any ideas?
> 1. One way to do it would be by dynamic power management. It would be
> nice to have wake-up mechanism at the block layer. Idle timer can run
> in the block layer or it can be implemented in the userland.
> ATM, this implies that the attached devices are powered down too
> (spindown). As spinning up takes quite some time, we can implement

For now, powering down controller when disks are spinned down would be
very nice first step.

When I forced disk to be spinned down (with power/state file)
controller actually survived power down/power up... unfortunately with
so long delay (~30 sec) that it is not usable in practice.

> So, I think option #1 is the way to go - implementing leveled dynamic
> power management infrastructure and adding support in the block layer.
> What do you think?

Would be nice :-).

(cesky, pictures)
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2006-09-18 12:09    [W:0.043 / U:6.092 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site