[PATCH 63/66] drm/i915: Remove superfluous posting reads after clear GGTT

Chris Wilson chris at chris-wilson.co.uk
Tue Jan 24 22:52:03 UTC 2017


The barrier here is not required - we apply the barrier before the range
is ever reused by the GPU instead.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 3be5a8bcce5d..078a3ff26b67 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -2166,7 +2166,6 @@ static void gen8_ggtt_clear_range(struct i915_address_space *vm,
 				      I915_CACHE_LLC);
 	for (i = 0; i < num_entries; i++)
 		gen8_set_pte(&gtt_base[i], scratch_pte);
-	readl(gtt_base);
 }
 
 static void gen6_ggtt_clear_range(struct i915_address_space *vm,
@@ -2191,7 +2190,6 @@ static void gen6_ggtt_clear_range(struct i915_address_space *vm,
 
 	for (i = 0; i < num_entries; i++)
 		iowrite32(scratch_pte, &gtt_base[i]);
-	readl(gtt_base);
 }
 
 static void i915_ggtt_insert_page(struct i915_address_space *vm,
@@ -2215,7 +2213,6 @@ static void i915_ggtt_insert_entries(struct i915_address_space *vm,
 		AGP_USER_MEMORY : AGP_USER_CACHED_MEMORY;
 
 	intel_gtt_insert_sg_entries(pages, start >> PAGE_SHIFT, flags);
-
 }
 
 static void i915_ggtt_clear_range(struct i915_address_space *vm,
-- 
2.11.0



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