[PATCH v2 9/9] drm/i915: use DMA_ATTR_PERSISTENT_STREAMING flag

David Stevens
2021-08-06T10:35:50Z

Use the new DMA_ATTR_PERSISTENT_STREAMING for long lived dma mappings
which directly handle CPU cache coherency instead of using dma_sync_*.

Signed-off-by: David Stevens <stevensd@chromium.org>
---
drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 4 +++-
drivers/gpu/drm/i915/i915_gem_gtt.c | 3 ++-
2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index 616c3a2f1baf..df982cfb4f34 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -48,7 +48,9 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme
src = sg_next(src);
}

- ret = dma_map_sgtable(attachment->dev, st, dir, DMA_ATTR_SKIP_CPU_SYNC);
+ ret = dma_map_sgtable(attachment->dev, st, dir,
+ DMA_ATTR_SKIP_CPU_SYNC |
+ DMA_ATTR_PERSISTENT_STREAMING);
if (ret)
goto err_free_sg;

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 36489be4896b..f27a849631f7 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -33,7 +33,8 @@ int i915_gem_gtt_prepare_pages(struct drm_i915_gem_object *obj,
PCI_DMA_BIDIRECTIONAL,
DMA_ATTR_SKIP_CPU_SYNC |
DMA_ATTR_NO_KERNEL_MAPPING |
- DMA_ATTR_NO_WARN))
+ DMA_ATTR_NO_WARN |
+ DMA_ATTR_PERSISTENT_STREAMING))
return 0;

/*
--
2.32.0.605.g8dce9f2422-goog