* Alex Deucher wrote: > On Thu, Apr 12, 2012 at 5:33 AM, Thierry Reding > wrote: > > 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? > > You should be able to do something like that already with dma_buf and > the drm prime infrastructure. There's even a drm driver for the udl > USB framebuffer devices. Using DRM PRIME requires user-space to be involved. I was thinking more along the lines of allowing a dumb DRM driver that only provides a CRTC to register with another driver so that it shows up as an output for the latter DRM device. Then again, having user-space control this may be more flexible. Performance- wise both should be about the same, right? What I don't quite understand yet is how the DMABUF would be synchronized on both ends. Is there some infra- structure to account for it or would I have to export two buffers and flip them during the vblank of the "consumer"? Thierry