1 files changed, 53 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.9/0180-drm-vc4-Fulfill-user-BO-creation-requests-from-the-k.patch b/target/linux/brcm2708/patches-4.9/0180-drm-vc4-Fulfill-user-BO-creation-requests-from-the-k.patch
new file mode 100644
index 0000000000..c0967b4639
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.9/0180-drm-vc4-Fulfill-user-BO-creation-requests-from-the-k.patch
@@ -0,0 +1,53 @@
+From cb8a5a1cf8cfd5b88fe641ada9a2dfb318d43c3f Mon Sep 17 00:00:00 2001
+From: Eric Anholt <eric@anholt.net>
+Date: Wed, 8 Feb 2017 15:00:54 -0800
+Subject: [PATCH] drm/vc4: Fulfill user BO creation requests from the kernel BO
+ cache.
+
+The from_cache flag was actually "the BO is invisible to userspace",
+so we can repurpose to just zero out a cached BO and return it to
+userspace.
+
+Improves wall time for a loop of 5 glsl-algebraic-add-add-1 by
+-1.44989% +/- 0.862891% (n=28, 1 outlier removed from each that
+appeared to be other system noise)
+
+Note that there's an intel-gpu-tools test to check for the proper
+zeroing behavior here, which we continue to pass.
+
+Signed-off-by: Eric Anholt <eric@anholt.net>
+---
+ drivers/gpu/drm/vc4/vc4_bo.c | 13 +++++++------
+ 1 file changed, 7 insertions(+), 6 deletions(-)
+
+--- a/drivers/gpu/drm/vc4/vc4_bo.c
++++ b/drivers/gpu/drm/vc4/vc4_bo.c
+@@ -208,21 +208,22 @@ struct drm_gem_object *vc4_create_object
+ }
+ 
+ struct vc4_bo *vc4_bo_create(struct drm_device *dev, size_t unaligned_size,
+-			     bool from_cache)
++			     bool allow_unzeroed)
+ {
+ 	size_t size = roundup(unaligned_size, PAGE_SIZE);
+ 	struct vc4_dev *vc4 = to_vc4_dev(dev);
+ 	struct drm_gem_cma_object *cma_obj;
++	struct vc4_bo *bo;
+ 
+ 	if (size == 0)
+ 		return ERR_PTR(-EINVAL);
+ 
+ 	/* First, try to get a vc4_bo from the kernel BO cache. */
+-	if (from_cache) {
+-		struct vc4_bo *bo = vc4_bo_get_from_cache(dev, size);
+-
+-		if (bo)
+-			return bo;
++	bo = vc4_bo_get_from_cache(dev, size);
++	if (bo) {
++		if (!allow_unzeroed)
++			memset(bo->base.vaddr, 0, bo->base.base.size);
++		return bo;
+ 	}
+ 
+ 	cma_obj = drm_gem_cma_create(dev, size);