On Thu, Apr 12, 2012 at 9:25 AM, Thierry Reding <thierry.reding@xxxxxxxxxxxxxxxxx> wrote: > * Alex Deucher wrote: >> On Thu, Apr 12, 2012 at 5:33 AM, Thierry Reding >> <thierry.reding@xxxxxxxxxxxxxxxxx> 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. Even then it could get tricky with synchronization depending on the hw. > > 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"? Performance should be about the same. The tricky part is synchronization. dma_buf is for sharing. There are ideas to make generic sync objects, but for now, it's up to the userspace components to handle it. Alex _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
