Re: [PATCH 00/12] ThinkPad embedded controller and hdaps drivers (version 2)

On 8/10/06, Andrew Morton <akpm-3NddpPZAyC0@public.gmane.org> wrote:
> This situation is still a concern.  From where did this additional register
> information come?
>
> Was it reverse-engineered?  If so, by whom and how can we satisfy ourselves
> of this?
>
> Was it from published documents?

Here's a more detailed explanation:

All the low level LPC register access is publicly documented in the
manual of the embedded controller. See [1] and in particular [2]. The
submitted thinkpad_ec code just follows these specs (very defensively
with and a lot of extra status checks, because some EC hangs were
reported in older versions). The only remaining information is about
the accelerometer-specific commands implemented by the firmware; the
public APS spec [3] and the mainline code based on this already
contain most of the this information, and a few corrections and
extentions were gleaned from the reverse-engineered the firmware code
[4]. If case you're wondering about the "opaque" function,
hdaps_check_ec(), then note that it's just code from the original
hdaps driver (following [3]) that's translated to use thinkpad_ec
instead of direct IO port access.


> Was it improperly obtained from NDA'ed documentation?

Absolutely not. I've never signed any NDA remotely related to this.
(and why I do so when the above sources already contain all the needed
information?)

BTW, I can't help wondering: do you have a similarly detailed account
for an appreciable fraction of the driver code in mainline?


> So hm.  We're setting precedent here and we need Linus around to resolve
> this.  Perhaps we can ask "Shem" to reveal his true identity to Linus (and
> maybe me) privately and then we proceed on that basis.

Sure, we can do this. Actually I've alredy e-mailed Linus to this
effect several days ago, before realizing he's off-line.


> "each of the Signed-off-by:ers should know the identity of the others".

How following the DCO's chain-of-trust model?

--- a/Documentation/SubmittingPatches
+++ b/Documentation/SubmittingPatches
@@ -296,7 +296,7 @@ can certify the below:

         (c) The contribution was provided directly to me by some other
             person who certified (a), (b) or (c) and I have not modified
-            it.
+            it, and the legal identity of that person is known to me.

        (d) I understand and agree that this project and the contribution
            are public and that a record of the contribution (including all


  Shem

[1]http://thinkwiki.org/wiki/Renesas_H8S/2161BV and in particular
[2]http://documentation.renesas.com/eng/products/mpumcu/rej0...
[3]http://www.almaden.ibm.com/cs/people/marksmith/tpaps.html
[4]http://forum.thinkpads.com/viewtopic.php?t=20958

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