target/linux/brcm2708/patches-4.9/0180-drm-vc4-Fulfill-user-BO-creation-requests-from-the-k.patch

   1 From cb8a5a1cf8cfd5b88fe641ada9a2dfb318d43c3f Mon Sep 17 00:00:00 2001
   2 From: Eric Anholt <eric@anholt.net>
   3 Date: Wed, 8 Feb 2017 15:00:54 -0800
   4 Subject: [PATCH] drm/vc4: Fulfill user BO creation requests from the kernel BO
   5  cache.
   6
   7 The from_cache flag was actually "the BO is invisible to userspace",
   8 so we can repurpose to just zero out a cached BO and return it to
   9 userspace.
  10
  11 Improves wall time for a loop of 5 glsl-algebraic-add-add-1 by
  12 -1.44989% +/- 0.862891% (n=28, 1 outlier removed from each that
  13 appeared to be other system noise)
  14
  15 Note that there's an intel-gpu-tools test to check for the proper
  16 zeroing behavior here, which we continue to pass.
  17
  18 Signed-off-by: Eric Anholt <eric@anholt.net>
  19 ---
  20  drivers/gpu/drm/vc4/vc4_bo.c | 13 +++++++------
  21  1 file changed, 7 insertions(+), 6 deletions(-)
  22
  23 --- a/drivers/gpu/drm/vc4/vc4_bo.c
  24 +++ b/drivers/gpu/drm/vc4/vc4_bo.c
  25 @@ -208,21 +208,22 @@ struct drm_gem_object *vc4_create_object
  26  }
  27
  28  struct vc4_bo *vc4_bo_create(struct drm_device *dev, size_t unaligned_size,
  29 -                            bool from_cache)
  30 +                            bool allow_unzeroed)
  31  {
  32         size_t size = roundup(unaligned_size, PAGE_SIZE);
  33         struct vc4_dev *vc4 = to_vc4_dev(dev);
  34         struct drm_gem_cma_object *cma_obj;
  35 +       struct vc4_bo *bo;
  36
  37         if (size == 0)
  38                 return ERR_PTR(-EINVAL);
  39
  40         /* First, try to get a vc4_bo from the kernel BO cache. */
  41 -       if (from_cache) {
  42 -               struct vc4_bo *bo = vc4_bo_get_from_cache(dev, size);
  43 -
  44 -               if (bo)
  45 -                       return bo;
  46 +       bo = vc4_bo_get_from_cache(dev, size);
  47 +       if (bo) {
  48 +               if (!allow_unzeroed)
  49 +                       memset(bo->base.vaddr, 0, bo->base.base.size);
  50 +               return bo;
  51         }
  52
  53         cma_obj = drm_gem_cma_create(dev, size);