DualHead card with HW acceleration

[Andy Ritger]

On Wed, 17 Aug 2005, Thomas Winischhofer wrote:

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> Andy Ritger wrote:
> > The NVIDIA X driver supports hw accelerated rotation.  Note that
> > the current support is for rotating an entire X screen, so to rotate
> > 2 DFPs driven by one GPU, you could setup 2 separate X screens on
> > one GPU, each X screen driving one DFP, and each X screen rotated.
> 
> Mind if I ask if this support is mainly done by hardware or by software
> (ie the driver)?

NVIDIA hardware doesn't natively do rotated scanout, if that's what
you're asking :)

The current implementation in the NVIDIA X driver accumulates
dirty regions as rendering touches the desktop (both X rendering
and direct rendering XvMC and OpenGL clients), and then uses the
3D engine, at opportune times, to rotate the regions into a shadow
surface that is scanned out.

(the 3D engine is overkill in the plain rotated case, but the same
paths are leveraged in the CI and RGB workstation overlay emulation
performed by the NVIDIA driver on Quadro GPUs).

Thanks,
- Andy


> Thomas
> 
> - --
> Thomas Winischhofer
> Vienna/Austria
> thomas AT winischhofer DOT net          http://www.winischhofer.net/
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