Re: [PATCH v6 1/2] ACPI: Add early console framework for DBGP/DBG2.

From: Grant Likely
Date: Tue Jun 04 2013 - 06:54:22 EST

On Fri, Oct 12, 2012 at 8:24 PM, Khalid Aziz <khalid@xxxxxxxxxxxxxx> wrote:
> On Wed, 2012-10-10 at 18:44 +0100, Matthew Garrett wrote:
>> On Wed, Oct 10, 2012 at 11:23:01AM +0800, Lv Zheng wrote:
>> > Microsoft Debug Port Table (DBGP or DBG2) is used by the Windows SoC
>> > platforms to describe their debugging facilities.
>> > DBGP:
>> > DBG2:
>> The license for these specifications only covers BIOS implementations,
>> not OS implementations. Has this had appropriate legal review?
> I agree with Matthew. There are potential legal issues with using
> DBGP/DBGP2 tables in Linux. I had added support for SPCR and DBGP tables
> many years ago (in early 2.6 kernel timeframe) before Microsoft added
> this new license. I pulled the code out (in 2.6.14, I think) after
> Microsoft added the new license to these tables. I agree with Matthew's
> interpretation that the license is clear only about BIOS vendors being
> allowed to use these tables. PCDP table in DIG64 spec was introduced to
> get around the legal issues with using SPCR and DBGP in Linux.
> License for DBGP/DBGP2 needs some legal review before this patch can go
> into Linux.

Matthew, can you point me at the license Microsoft is using for the
DBG2 table? I can download the document from Microsoft's site without
seeing any reference to it being licensed only for BIOS implementers.
All I see is a "this document is provided 'as-is', blah blah blah"
blurb at the beginning of the document. It may be that Microsoft has
changed the license on this document in the last 6 months.

I asked some of my contacts at Microsoft about this and was told that
the DBG2 spec was supposed to be freed up; but I wasn't able to get
anything absolutely confirmed or in writing.

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