Re: SATA ALPM min_power causes > 10s delay on resume

["Jeffrey W. Baker" <jwbaker@gmail.com>]

On Mon, 2008-08-25 at 20:14 -0700, Jeffrey W. Baker wrote:
> On Mon, 2008-08-25 at 17:14 -0700, Grant Grundler wrote:
> > On Sun, Aug 24, 2008 at 10:27 AM, Jeffrey W. Baker <jwbaker@gmail.com> wrote:
> > > I started using the min_power ALPM setting on my ThinkPad to save power
> > > (which works great, thanks!) but it causes a small problem.  When the
> > > machine resumes from suspend-to-ram it hangs for about 10s and then
> > > prints this on the console:
> > >
> > > ata1: COMRESET failed (errno=-16)
> > >
> > > It then proceeds normally.  The full messages are:
> > >
> > > ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
> > > ata1.00: configured for UDMA/100
> > > ata1: failed to recover some devices, retrying in 5 secs
> > > ata1: soft resetting link
> > > ata1: SATA link down (SStatus 611 SControl 300)
> > > ata1: failed to recover some devices, retrying in 5 secs
> > > ata1: hard resetting link
> > > ata1: port is slow to respond, please be patient (Status 0x80)
> > > ata1: COMRESET failed (errno=-16)
> > > ata1: hard resetting link
> > > ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
> > 
> > Can you enable CONFIG_PRINTK_TIME in your kernel?
> 
> Output follows ...
> 
> > It sounds like the ahci driver is having problems spinning up
> > the disk after putting it into a "low power state" (which I
> > have no clue might be). Getting more accurate time
> > stamps might be a useful additional clue.
> 
> The disk is an SSD so there's no need for delay to allow it to spin
> up.

I just did an experiment, and a workaround for this problem is to enable
max_performance immediately before sleep and return to min_power during
resume.

-jwb