From f294f3a4a87da4c8beed00597a948537de644131 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Tue, 21 Jan 2020 22:24:41 +0000
Subject: drm/i915: Clear the GGTT_WRITE bit on unbinding the vma
Git-commit: 5424f5d79472c5c20500e8d3eee356a4c6fef3d9
Patch-mainline: v5.7-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

While we do flush writes to the vma before unbinding (to make sure they
go through the right detiling register), we may also be concurrently
poking at the GGTT_WRITE bit from set-domain, as we mark all GGTT vma
associated with an object. We know this is for another vma, as we
are currently unbinding this one -- so if this vma will be reused, it
will be refaulted and have its dirty bit set before the next write.

Closes: https://gitlab.freedesktop.org/drm/intel/issues/999
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200121222447.419489-1-chris@chris-wilson.co.uk
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/i915_vma.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 4ff380770b32..4999882fbceb 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -1228,9 +1228,15 @@ int __i915_vma_unbind(struct i915_vma *vma)
 		 * before the unbind, other due to non-strict nature of those
 		 * indirect writes they may end up referencing the GGTT PTE
 		 * after the unbind.
+		 *
+		 * Note that we may be concurrently poking at the GGTT_WRITE
+		 * bit from set-domain, as we mark all GGTT vma associated
+		 * with an object. We know this is for another vma, as we
+		 * are currently unbinding this one -- so if this vma will be
+		 * reused, it will be refaulted and have its dirty bit set
+		 * before the next write.
 		 */
 		i915_vma_flush_writes(vma);
-		GEM_BUG_ON(i915_vma_has_ggtt_write(vma));
 
 		/* release the fence reg _after_ flushing */
 		ret = i915_vma_revoke_fence(vma);
@@ -1250,7 +1256,8 @@ int __i915_vma_unbind(struct i915_vma *vma)
 		trace_i915_vma_unbind(vma);
 		vma->ops->unbind_vma(vma);
 	}
-	atomic_and(~(I915_VMA_BIND_MASK | I915_VMA_ERROR), &vma->flags);
+	atomic_and(~(I915_VMA_BIND_MASK | I915_VMA_ERROR | I915_VMA_GGTT_WRITE),
+		   &vma->flags);
 
 	i915_vma_detach(vma);
 	vma_unbind_pages(vma);
-- 
2.28.0