While this series is more correct from the DMA API point of view, it is also much heavier as it strictly disables the use of any cache on all user-space mapped BOs, and is also much more restricted in terms of which memory it can use.
I have a v4 in the works that lets us use TTM for user-mapped objects and only falls back to using the DMA API for kernel-only objects (fences & PBs basically). Will push it shortly but wanted to signal this revision as deprecated in the meantime.
On Fri, Jun 27, 2014 at 8:22 PM, Alexandre Courbot acourbot@nvidia.com wrote:
v2 was doing some pretty nasty things with the DMA API, so I took a different approach for this v3.
As suggested, this version uses ttm_dma_populate() to populate BOs. The reason for doing this was that it would entitle us to using the DMA sync functions, but since the memory returned is already coherent anyway, we do not even need to call these functions anymore.
So this series has turned into 2 small patches:
- The first attempts to make it more obvious that Nouveau can use different
ways to populate TTs, and make it possible to choose which method to use from a single place.
- The second leverages this work to select the DMA allocator to populate TTs
on ARM.
Doing this solves all our coherency problems with Nouveau on Tegra, and hopefully makes the code easier to read in the process.
Alexandre Courbot (2): drm/nouveau: cleanup TTM population logic drm/nouveau: use DMA TT population method on ARM
drivers/gpu/drm/nouveau/nouveau_bo.c | 63 ++++++++++++++++++----------------- drivers/gpu/drm/nouveau/nouveau_drm.h | 11 ++++++ drivers/gpu/drm/nouveau/nouveau_ttm.c | 17 ++++++++++ 3 files changed, 61 insertions(+), 30 deletions(-)
-- 2.0.0