Am 12.03.2018 um 18:24 schrieb Daniel Vetter: > On Fri, Mar 09, 2018 at 08:11:40PM +0100, Christian K??nig wrote: >> This set of patches adds an option invalidate_mappings callback to each >> DMA-buf attachment which can be filled in by the importer. >> >> This callback allows the exporter to provided the DMA-buf content >> without pinning it. The reservation objects lock acts as synchronization >> point for buffer moves and creating mappings. >> >> This set includes an implementation for amdgpu which should be rather >> easily portable to other DRM drivers. > Bunch of higher level comments, and one I've forgotten in reply to patch > 1: > > - What happens when a dma-buf is pinned (e.g. i915 loves to pin buffers > for scanout)? When you need to pin an imported DMA-buf you need to detach and reattach without the invalidate_mappings callback. > - pulling the dma-buf implementations into amdgpu makes sense, that's > kinda how it was meant to be anyway. The gem prime helpers are a bit too > much midlayer for my taste (mostly because nvidia wanted to bypass the > EXPORT_SYMBOL_GPL of core dma-buf, hooray for legal bs). We can always > extract more helpers once there's more ttm based drivers doing this. Yeah, I though to abstract that similar to the AGP backend. Just moving some callbacks around in TTM should be sufficient to de-midlayer the whole thing. Thanks, Christian. > > Overall I like, there's some details to figure out first. > -Daniel
