Re: Sata link_power_management_policy questions

[Robert Hancock <hancockrwd@gmail.com>]

On 06/22/2009 12:50 PM, Patrick Voegeli Olivera wrote:
> Hi there,
>
> I have a laptop with Sata set to native mode and ahci enabled in the
> bios. In ubuntu, I can see
> /sys/class/scsi_host/host0/link_power_management_policy for host0, host1
> and host2, but if I read any of those using cat they always will return
> max_performance, even if I echo min_power or medium_power and it gives
> no errors:
>
> root@patrick-laptop:~# cat
> /sys/class/scsi_host/host0/link_power_management_policy
> max_performance
> root@patrick-laptop:~# echo min_power >
> /sys/class/scsi_host/host0/link_power_management_policy
> root@patrick-laptop:~# cat
> /sys/class/scsi_host/host0/link_power_management_policy
> max_performance
>
> I've tried to look around for a solution, but I haven't found anything
> useful. Is this a feature that depends on the HDD? Does the hard drive
> need to be sata 2/300 or should it also work with sata 1/150? Is it just
> that my laptop doesn't support it?
>
> Since my HDD is sata150, I've tried with another HDD and I had the same
> problem. I don't know if it was sata2 compliant, though.
>
> My laptop has intel chipsets. Namely, the 965gm (with x3100 graphics)
> northbridge and I think it has a ich8 southbridge.
>
> Any ideas on what to try?

Please post your dmesg output and hdparm -I output for the drive. Also 
cc-ing linux-ide.