Nouveau - Jun 2015 - [PATCH] nvc0: create screen fence objects with coherent attribute

This is required on non-coherent architectures to ensure the value of
the fence is correct at all times. Failure to do this results in the
display freezing for a few seconds every now and then on Tegra.

The NOUVEAU_BO_COHERENT is a no-op for coherent architectures, so behavior
on x86 should not be affected by this patch.

Signed-off-by: Alexandre Courbot <acourbot at nvidia.com>
---
 src/gallium/drivers/nouveau/nvc0/nvc0_screen.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
b/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
index 5936d05a5b93..307cf5f9cd75 100644
--- a/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
+++ b/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
@@ -610,6 +610,7 @@ nvc0_screen_create(struct nouveau_device *dev)
    struct nouveau_pushbuf *push;
    uint64_t value;
    uint32_t obj_class;
+   uint32_t flags;
    int ret;
    unsigned i;
 
@@ -660,8 +661,11 @@ nvc0_screen_create(struct nouveau_device *dev)
    screen->base.base.get_video_param = nouveau_vp3_screen_get_video_param;
    screen->base.base.is_video_format_supported =
nouveau_vp3_screen_video_supported;
 
-   ret = nouveau_bo_new(dev, NOUVEAU_BO_GART | NOUVEAU_BO_MAP, 0, 4096, NULL,
-                        &screen->fence.bo);
+   flags = NOUVEAU_BO_GART | NOUVEAU_BO_MAP;
+   if (dev->drm_version >= 0x01000202)
+      flags |= NOUVEAU_BO_COHERENT;
+
+   ret = nouveau_bo_new(dev, flags, 0, 4096, NULL, &screen->fence.bo);
    if (ret)
       goto fail;
    nouveau_bo_map(screen->fence.bo, 0, NULL);
-- 
2.4.4