[ltp] Re: IBM HDAPS Someone interested?

Lenz Grimmer linux-thinkpad@linux-thinkpad.org
Mon, 20 Jun 2005 19:04:35 +0200


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Hi,

let me add my 2 cents here, as I have been toying around with this idea,
too..

Vojtech Pavlik wrote:

> Indeed, but there is a zillion of different approaches to an A/D. I'm
> quite sure IBM have rolled their own directly on the mainboard.
> 
> The main question is on which bus and which address it lives and what
> is the programming interface. It's not something Analog Devices would
> know.
> 
> It can be on some monitoring chip living on the SMBus (most likely)
> or coupled directly to the ACPI bridge on PCI, or anywhere else in
> the system.

I tried monitoring the output of the embedded controller register dump
that the "ibm-acpi" kernel module provides, using the following command
and then moving the Laptop (Thinkpad T42) to trigger changes:

  watch -n1 cat /proc/acpi/ibm/ecdump

Alas, there wasn't really a pattern that convinced me that the chip
actually is monitored via this controller. But of course it may not harm
if somebody else double checks this.

> Well, some piece of software needs to park the HDD when the notebook
> is falling, and that piece of software should better be running since
> the notebook is powered on. Hence my suspicion it's in the BIOS. It
> doesn't have to be visible to the user, at all.

On Windows, you need to run a separate tray application that enables the
protection. So it seems like it's implemented in "userspace". It may be
worth debugging what this Window applet actually does...

Bye,
	LenZ
- --
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 Lenz Grimmer <lenz@grimmer.com>                             -o)
 [ICQ: 160767607 | Jabber: LenZGr@jabber.org]                /\\
 http://www.lenzg.org/                                       V_V
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