[Mesa-dev] About OpenGL QB stereo support..

[Alex Deucher]

On Thu, Jan 13, 2011 at 2:35 PM, Ian Romanick <idr at freedesktop.org> wrote:
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> On 01/13/2011 06:51 AM, Stefanos A. wrote:
>> On Thu, 13 Jan 2011 14:18:01 +0200, Corbin Simpson
>> <mostawesomedude at gmail.com> wrote:
>>
>>> 12, 2011 at 3:47 PM, rtfss none <rtfss1 at gmail.com> wrote:
>>>> Hi,
>>>>
>>>> first sorry if not is the correct place to post it but I was thinking
>>>> that with open source Sandy Bridge and AMD 68xx cards support that
>>>> ship with Displayport 1.2 (AMD only) and HDMI1.4(both) connectors
>>>> supporting
>>>> 3d stereo output if could mesa developers expose support for it.. i.e.
>>>> mesa ogl driver expose support for OGL QB stereo.. of course that
>>>> perhaps should require changes to drm stack or both amd and intel open
>>>> source drivers to setup
>>>> correct stereo frame packing output in this outputs.. that could add
>>>> an advantage of open source drivers to propietary drivers which only
>>>> expose ogl stereo support for professional cards.. and even then i
>>>> think there is no currently support for ogl qb stereo support via hdmi
>>>> 1.4 nor in Nvidia and AMD worlds.. also this could be a good effort to
>>>> port all stereo madness to linux now that seem even MVC hardware
>>>> decoding is supported on both Sandy Bridge and AMD 68xx cards.. that
>>>> could be exposed via VAAPI for SandyBrige (I'm posting on libva dev
>>>> list) or new OpenDecode AMD API which already exposes that support
>>>> (currently Windows world only but some OCL developers have asked AMD
>>>> to support also Linux)..
>>> DRI and GLX have all the correct support for GL_STEREO, but none of
>>> the open drivers implement it as far as I know. This would probably be
>>> a non-trivial thing to implement.
>>
>> Do we have the necessary documentation to support quad-buffer stereo?
>
> I'm not sure.  I think HDMI does stereo differently than the traditional
> approach.  The traditional way is to just switch between the left and
> right buffers each vertical blank.  To get this working we'll need some
> support in X and in the kernel.  We don't need any documentation to do
> the old way, but if HDMI is, in fact, different, we may need some
> additional documentation.

HDMI indeed does it differently; in fact there are several methods
supported depending on the hw.  There are special HDMI 3D packets
required for the source and the sink decide what methods they each
support and which one they are going to use.  See this page for more
info:
http://thedigitallifestyle.com/cs/tdl/b/custom/archive/2010/03/26/making-sense-out-of-hdmi-1-4-performance-and-the-cea_1920_s-861-infoframes-_2d00_-installment-027.aspx
The data is sent to the TV differently depending on the method the
source and sink work out.

Alex

>
> Since HDMI is proprietary, it may be (legally) impossible to make some
> of the documentation public.
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