Hi,
I've tested these two patches (in drm-intel-nightly, but also in CrOS kernel v3.14) and they seem just enough for what we want to do: the idea is to create a GEM bo in one process and pass the prime handle of the it to another process, which in turn uses the handle only to map and write. This could be useful for Chrome OS architecture, where the Web content ("unpriviledged process") maps and CPU-draws a buffer, which was previously allocated in the GPU process ("priviledged process").
I'm using a modified igt mostly to test these things. PTAL here: https://github.com/tiagovignatti/intel-gpu-tools/commits/prime_mmap
Thank you,
Tiago
Daniel Thompson (1): drm: prime: Honour O_RDWR during prime-handle-to-fd
Tiago Vignatti (1): drm/i915: Use CPU mapping for userspace dma-buf mmap()
drivers/gpu/drm/drm_prime.c | 10 +++------- drivers/gpu/drm/i915/i915_gem_dmabuf.c | 21 ++++++++++++++++++++- include/uapi/drm/drm.h | 1 + 3 files changed, 24 insertions(+), 8 deletions(-)