Re: [RFC 4/4] drm: Add NVIDIA Tegra support

* Sascha Hauer wrote:

You might want to have a look at the sdrm patches I recently posted to
dri-devel and arm Linux Kernel. Among other things they allow to
register crtcs/connectors/encoders seperately so that each of them can
have its own representation in the devicetree. I haven't looked into
devicetree support for DRM, but with or without devicetree the problem
that we do not have a single PCI card for registering all DRM components
is the same.

I'll do that. One interesting use-case that's been on my mind for some time
is if it would be possible to provide a CRTC via DRM that isn't part of the
SoC or DRM "device" but which can display a framebuffer prepared by the DRM
framework.

In other words I would like to use the Tegra hardware to render content into
a framebuffer (using potentially the 3D engine or HW accelerated video
decoding blocks) but display that framebuffer with a CRTC registered by a
different driver (perhaps provided by a PCIe or USB device).

I think such a setup would be possible if the CRTC registration can be
decoupled from the DRM driver. Perhaps sdrm even supports that already?

Thierry