[Mesa-dev] S2TC - yet another attempt to solve the "S3TC issue"

Ian Romanick idr at freedesktop.org
Tue Aug 9 15:23:46 PDT 2011

Hash: SHA1

On 08/09/2011 02:29 AM, Rudolf Polzer wrote:
> On Tue, Aug 09, 2011 at 02:01:44AM -0700, Jose Fonseca wrote:
>> ----- Original Message -----
>>> On Mon, Aug 08, 2011 at 05:49:09AM -0700, Jose Fonseca wrote:
>>>> ----- Original Message -----
>>>>> The suggestion however is to include a S2TC-like method with
>>>>> Mesa, to
>>>>> basically
>>>>> make sure that in the long run NO distro has no support for S3TC
>>>>> uploading,
>>>>> without requiring an extra decision in each distro.
>>>> I wouldn't oppose bundling S2TC for software renderers, but
>>>> enabling S3TC decompression on hardware is an orthogonal matter,
>>>> which depends on the licensing terms between the IHV and S3.
>>>> If you wanna fix this, convince IHVs to fully license the S3TC use
>>>> in their hardware for Linux.  So far the only IHV that _seems_ to
>>>> have such wide cross-OS license is NVIDIA.
>>>> I think it would be good to add a FAQ about this in the docs.  But
>>>> I'm done with this stupid thread.  I'll enjoy my vacation and stop
>>>> wasting time with this nonsense.
>>> In other words: you want the EXISTING support in Mesa to upload S3TC
>>> compressed
>>> textures (pre-compressed, not runtime compressed) to the hardware
>>> removed.
>> I couldn't let this statements go unchallenged..
>> The option in question is disabled by default, and I don't agree this is
>> inducing in infringement in any way as we always highlighted the S3TC
>> pitfalls in the mailing lists, and the IHV's S3TC licensing terms have not
>> been disclosed, but I agree that at the very least we should better document
>> this option in docs/patents.txt, to avoid misunderstandings as you're having,
>> and yes, probably also have the option disabled by default with a configure
>> option, as we do with floating point textures, which the drivers may override
>> or not, as the breadth of S3TC license of the target hardware is known.
>> Thanks for pointing this issue out, Rudolf.  Thanks for playing devil's
>> advocate in a public forum, and forcing us to take a stricter stand on this
>> matter.  I am confused though, because I thought you were trying to help the
>> Linux community, not the patent trolls.
> I was trying to help the Linux communtiy, but apparently I failed.
> Looks like all this work I did was for nothing. Nothing is appreciated, all is
> "Not Invented Here".

"Not invented here" has nothing to do with it.  You did some fine work
that will help the software rasterizers.

> How else should I have brought this up? I still don't understand WHY this is an
> issue. Is US patent law really that retarded? I still can't believe this, as to
> me that would mean that Apache would have needed a patent license in order to
> transport GIF files back then (or at least, to assign the content type
> "image/gif" in the default config).

It's like any sort of licensing.  If I own some particular thing, I can
license you to use it under any terms I want.  It turns out that the
licensing terms for the S3TC patents are *extremely* restrictive.
Combine that with the licensing fees being the primary source of S3's
income, and there can be only trouble.
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