3D support for Displaylink devices

[Alex Deucher]

On Fri, Jun 3, 2011 at 5:00 AM, Prasanna Kumar T S M
<prasanna_tsm_kumar at yahoo.co.in> wrote:
> On 03-06-2011 00:16, Alan Cox wrote:
>>>
>>> The window system needs support for splitting rendering and display.
>>> In X these are currently tied together.  The only real obstacle is
>>> fixing this in X.  However, this is a lot of work.  Dave Airlie has
>>> started working on this, but it's not really usable yet.   See:
>>> http://airlied.livejournal.com/71734.html
>>> http://cgit.freedesktop.org/~airlied/xserver/log/?h=drvlayer
>>
>> In the windows world it basically works by 'borrowing' the real graphics
>> card for rendering and then doing the damage list/compression/uplink.
>>
>> So its basically a *very* strange CRTC/scanout. To most intents and
>> purposes plugging one into an i915 say is an extra i915 head, and indeed
>> you can sensibly display the same scanout buffer on both real and link
>> heads.
>>
>> Alan
>>
> Why not tell X that DisplayLink device connected is a monitor (like
> connecting a projector) so that Intel driver will take care of all the 3D
> support (at least for Compiz) and video acceleration, only mode setting and
> data transfer from memory can be taken care by a DisplayLink driver. This
> may be a **very** bad way of implementing and may be hypothetical but if
> there is a possibility it will dramatically improve multi monitor support in
> X. I guess "Rotate and Resize" extensions can be supported easily if such a
> thing is implemented.
>

Patches welcome.  It's still a lot of work.

Alex