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From bea96046b4245e9abd65ed7acfed9adfd5f6c639 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Thu, 3 Mar 2011 23:43:02 +0000
Subject: [PATCH] drm/i915: Gen4+ has non-power-of-two strides

In c2e0eb16707, we started checking that the buffer was the correct size
for tiled access by ensuring that the size was a multiple of tiles.
However, gen4+ complicates the issue by allowing any multiple of 4096
bytes for the stride and so the simple check based on a power-of-two
stride was failing for valid bo.

Reported-by: Dan Williams <dcbw@redhat.com>
Reported-by: Robert Hooker <sarvatt@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_tiling.c |   29 ++++++++++++++---------------
 1 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_tiling.c b/drivers/gpu/drm/i915/i915_gem_tiling.c
index 79a04fd..654f350 100644
--- a/drivers/gpu/drm/i915/i915_gem_tiling.c
+++ b/drivers/gpu/drm/i915/i915_gem_tiling.c
@@ -215,6 +215,19 @@ i915_tiling_ok(struct drm_device *dev, int stride, int size, int tiling_mode)
 		}
 	}
 
+	if (INTEL_INFO(dev)->gen >= 4) {
+		/* 965+ just needs multiples of tile width */
+		if (stride & (tile_width - 1))
+			return false;
+	} else {
+		/* Pre-965 needs power of two tile widths */
+		if (stride < tile_width)
+			return false;
+
+		if (stride & (stride - 1))
+			return false;
+	}
+
 	if (IS_GEN2(dev) ||
 	    (tiling_mode == I915_TILING_Y && HAS_128_BYTE_Y_TILING(dev)))
 		tile_height = 32;
@@ -226,21 +239,7 @@ i915_tiling_ok(struct drm_device *dev, int stride, int size, int tiling_mode)
 		tile_height *= 2;
 
 	/* Size needs to be aligned to a full tile row */
-	if (size & (tile_height * stride - 1))
-		return false;
-
-	/* 965+ just needs multiples of tile width */
-	if (INTEL_INFO(dev)->gen >= 4) {
-		if (stride & (tile_width - 1))
-			return false;
-		return true;
-	}
-
-	/* Pre-965 needs power of two tile widths */
-	if (stride < tile_width)
-		return false;
-
-	if (stride & (stride - 1))
+	if (size % (tile_height * stride))
 		return false;
 
 	return true;
-- 
1.7.4.1