Re: Questions about libdrm_intel and way to share physical memory between CPU and GPU

On Fri, 27 May 2011 14:37:45 -0700, "Segovia, Benjamin" benjamin.segovia@intel.com wrote:

Hello gurus,

I have two question mostly regarding libdrm_intel

1/ What is the difference between drm_intel_bo_map and drm_intel_gem_bo_map_gtt ?

bo_map uses the CPU domain, and so is CPU linear (needs sw detiling). bo_gtt_map uses the uncached [WC] GTT domain, and so is GPU linear (detiling is performed by the hardware using a fence).

2/ Will it be possible (or is it already possible) to directly share a regularly allocated piece of physical memory? Typical use case is the following one using OpenCL API:

Yes. I've proposed a vmap interface to bind user-pages into the GTT, similar to a completely unused bit of TTM functionality. -Chris