3D support for Displaylink devices

[Rob Clark]

On Mon, May 30, 2011 at 12:30 PM, PRASANNA KUMAR
<prasanna_tsm_kumar at yahoo.co.in> wrote:
> USB graphics devices from displaylink does not have 3D hardware. To get 3D
> effects (compiz, GNOME 3, KWin, OpenGL apps etc) with these device in Linux
> the native (primary) GPU can be used to provide hardware acceleration. All
> the graphics operation is done using the native (primary) GPU and the end
> result is taken and send to the displaylink device. Can this be achieved? If
> so is it possible to implement a generic framework so that any device (USB,
> thunderbolt or any new technology) can use this just by implementing device
> specific (compression and) data transport? I am not sure this is the correct
> mailing list.

fwiw, this situation is not too far different from the SoC world.  For
example, there are multiple ARM SoC's that share the same IMG/PowerVR
core or ARM/mali 3d core, but each have their own unique display
controller..

I don't know quite the best way to deal with this (either at the
DRM/kernel layer or xorg driver layer), but there would certainly be
some benefit to be able to make DRM driver a bit more modular to
combine a SoC specific display driver (mostly the KMS part) with a
different 2d and/or 3d accelerator IP.  Of course the (or some of the)
challenge here is that different display controllers might have
different memory mgmt requirements (for ex, depending on whether the
display controller has an IOMMU or not) and formats, and that the flip
command should somehow come via the 2d/3d command stream.

I have an (experimental) DRM/KMS driver for OMAP which tries to solve
the issue by way of a simple plugin API, ie the idea being to separate
the PVR part from the OMAP display controller part more cleanly.  I
don't think it is perfect, but it is an attempt.  (I'll send patches
as an RFC, but wanted to do some cleanup first.. just haven't had time
yet.)  But I'm definitely open to suggestions here.

BR,
-R


> Thanks,
> Prasanna Kumar
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