Re: [PATCH] libata: Add ALPM power state accounting to the AHCI driver

[Tejun Heo <tj@kernel.org>]

Hello,

Arjan van de Ven wrote:
> sigh. so I moved all the generic logic generic, and left the ahci
> specific code specific to ahci. I put the logic there where it was
> easy to implement, and there where the other link power management
> controls are (in sysfs). If that's not good enough, I'm out of my skills
> in the libata world to be honest, and would like to ask you to implement
> that instead. let me know what sysfs looks like and I'll adjust
> powertop to it....

The reason why we have sysfs attributes which should have been at link
layer at host was that it originally was for ahci alpm which is host
specific feature which got extended to something somewhat generic.
Now another pm feature which should belong to link is added to host
following the precedence.

Then again, it's also true that nobody really cares about ATA PM
features enough during past couple of years so I really don't want to
prevent the feature you're trying to add.  It would be best if there's
someone who would pick it up and implement proper infrastructure but
well that doesn't seem to be happening anytime soon.

So, I don't know.  That's the concern I have but I don't want to nack
your change either.  One thing is at least make those functions take
ata_link isntead of ata_port as there's nothing port specific about
those.  Jeff, what do you think?

Thanks.

-- 
tejun