Re: [PATCH] SATA / AHCI: Do not play with the link PM during suspend to RAM

Hello,

On 08/17/2010 11:28 PM, Stephan Diestelhorst wrote:

2010/8/17 Tejun Heo [off-list ref]:

quoted

On 08/17/2010 12:51 PM, Stephan Diestelhorst wrote:

quoted

I *think* I have applied the patch correctly. Please find a copy of
"git show" in the build directory attached. This should be the right
thing, shouldn't it?

quoted

Maybe I forgot to speify a particular debug option / verbosity?

quoted

I've also confirmed that the "XXX ahci_set_ipm" is present in
libahci.ko. So either I've screwed up badly when compiling the initrd,
the code is not executed or the printout does not make it into any
logfile anymore.

Yeah, that's weird.  You're enabling IPM, right?

Erm... Honestly, I have no clue. What is IPM? How do I enable it? This is a
Kubuntu Lucid 10.04 distribution, and I have not touched too much. In
particular, the kernels have been from upstream git, just with the Ubuntu config
copied over.

Maybe it is just not enabled? I am guessing that IPM might be IDE power
management? Or intelligent, integrated? Google turns up this email thread
as one of the first hits and nothing else conclusive.

It's interface power management, also called link power management.
You can check whether it's enabled by

$ cat /sys/class/scsi_host/host0/link_power_management_policy

If it says max_performance, it's disabled.  If it says anything else,
it's enabled.

Thanks.

-- 
tejun