[PATCH] AHCI powersaving and port-stopping (2.6.22-rc4)

[Török Edvin]

On 6/14/07, rami jiossy <sramij at yahoo.com> wrote:
>
> i've tried the attached patch for kernel 2.6.22-rc4. it saves around ~1W.

I have tried a combination of Kristen's ALPM patch, and Tejun's port
stopping patch.
It saves 1.2W iff:
* link_power_management_policy is min_power
* /sys/module/libata/parameters/powersave is 2 (DIPS), or 5 (DIPS/static)

If I turn off link_power_management (set to max_performance) the
system looses connection with my sata device completely (need to
reboot to regain).

If I use anything else but powersave modes 2 or 5 I get no powersavings at all.

Would it be worth integrating powersave mode 2 (DIPS) into the ALPM patch?


P.S.: the ahci force enable patch still has some issues: spurious IRQs
sometimes, and
IDE devices gone. I've managed to enable the IDE controller
separately, allocate resources, but libata can't communicate with it
yet. Also it doesn't seem to work on ICH6 at all, only ICH7.
An updated version is available here:
http://edwintorok.googlepages.com/patch_ahci.patch.

Best regards,
--Edwin