Re: IBM HDAPS Someone interested?

From: Alejandro Bonilla
Date: Mon Jun 20 2005 - 18:11:29 EST


Pavel Machek wrote:

Hi!

Apple connects their accelerometer over i2c, see:

http://www.kernelthread.com/software/ams/

For some reverse engineering attempts, see:

http://www.paul.sladen.org/thinkpad-r31/accelerometer.html

According to IBM, it is *not* enabled during system bootup:

http://www-307.ibm.com/pc/support/site.wss/document.do?lndocid=MIGR-53167

According to another text, BIOS know how to test accelerometer in some
kind of self test. Aha, here's the most interesting text:

http://www-307.ibm.com/pc/support/site.wss/document.do?lndocid=MIGR-53432

According to this text:

typical free-fall takes 300msec, but head unloading takes
300-500msec. [So I had my computation right ;-)] ... "therefore, it is
too late to start head unloading after detecting free fall"...

They really try to detect conditions just before free fall... and it
does not sound that difficult.

Another clever trick is that if user is still using the mouse, machine
is probably not in free fall ;-). In pdf, they also mention few
.sys files. They should probably be disassembled to learn how the
interface works (hint hint), actually exported symbol names should be
quite helpfull in determining what function is the interesting one.

Pavel


Pavel,

Thanks for all this information and to everyone providing data. This is really want we want. But We need to know how to talk to the chip before getting any on these math results to work.

Try what Lenz said: watch -n1 cat /proc/acpi/ibm/ecdump

.Alejandro
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/