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SubjectRe: Notebook disk spindown
On Sat, 9 Sep 2000, Russell King wrote:

> Andre Hedrick writes:
> > You know that it would take me 25 minutes or less to fix the code if I had
> > a full native taskfile. This would allow a (void *)(void) to be set in
> > kernel apmd and have all the drive data and callouts.
> Andre,
> I totally fail to see how taskfile will fix the problem of apmd not
> allowing my laptop to automatically suspend or hibernate.

I did to until I asked somebody, then thought about it, read some more,
and requestioned the notion, and then it seemed reasonable.

If apmd could issue a WIN_STANDBY value and execute WIN_STANDBYNOW1 then
the drive would know the thresholds to attempt a "suspend". Where as an
issue of WIN_SLEEPNOW1 would "hibernate" the drive.

> Please explain how the ability to suspend/hibernate, which seems to
> be dependent on apmd has to do with whether or not the kernel
> provides taskfile, which apmd would not use.

If there were callable ioctl's or callout functions, apmd could actively
control suspend/hibernate and apm-drive power thresholds to increase
battery runtime. At least this was the intent of the additions set
forward by the drive guys, as explained to me.

> Please, for your own sake, think about the problem being discussed
> before posting "taskfile would fix that" comments.

I have and offered it to the folks at linuxcare the apmd guys.
The ideas were to create an ioctl pair that would/could knock-out a drive
and preserve the settings, because the reset command to wake it up flushes
the settings. Thus after the wakeup reset, and a checkpower-loop for
ready-status in a passive drive query, the completion of the command would
set the drive and host back to pre- suspend/hibernate mode.

This in combination of the bios telling apmd to do something, apmd now can
parallel the bios if there is a problem and correct if possible.

Once I get my laptop, I will verify this and send you the results.

Now if I missed the initial point, I apologize.


Andre Hedrick
The Linux ATA/IDE guy

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