[ltp] [PATCH] 2.6.17: Unload disks heads before powering down

[Shem Multinymous]

Hi,

On 9/26/06, Henrique de Moraes Holschuh <hmh@hmh.eng.br> wrote:
> > Any real drawback to doing an UNLOAD IMMEDIATE instead of
> > STANDBY IMMEDIATE?
> Is Unload Immediate widely supported?

Just on newer disks, and the capability is often not reported
(http://thinkwiki.org/wiki/Problem_with_APS_harddisk_parking).

I guess it could try UNLOAD IMMEDIATE, and fall back if it returns
error (like the hdaps_protect code does given the right parameters).

> > I'm getting a spindown on reboot (i.e., shutdown) even without the SuSE
> > patch.
>
> Check the userspace scripts too.  They may be doing it (get rid of hdparm
> and userspace won't spin down disks anymore).  Add some printk on libata-eh
> (2.6.18) to track down when *_eh_suspend is called...

Right. I'll try an instrumented kernel later.

swsusp and uswsusp don't have the spin-down issue, right?

> 2.6.18 has the new Linus way of doing PM, AFAIK.  Not to mention the
> entirely new libata EH path.

Sorry, I forgot: the 2.6.17.4 kernel I tried had the tj libata patches
applied. So it closer to 2.6.18 than 2.6.17.x.
I think I indeed didn't see these spin-downs with the old libata code.

  Shem