3D support for Displaylink devices

[Prasanna Kumar T S M]

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.