From 4ec8f58d042d7fe0dab570fed35a438759645ca8 Mon Sep 17 00:00:00 2001
From: Keith Packard <keithp@keithp.com>
Date: Thu, 6 Dec 2007 15:12:21 -0800
Subject: [PATCH] i915: wait for buffer idle before writing relocations

When writing a relocation entry, make sure the target buffer is idle,
otherwise the GPU may see inconsistent data.
---
 shared-core/i915_dma.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/shared-core/i915_dma.c b/shared-core/i915_dma.c
index 090ac80a..18d2482e 100644
--- a/shared-core/i915_dma.c
+++ b/shared-core/i915_dma.c
@@ -751,6 +751,13 @@ int i915_apply_reloc(struct drm_file *file_priv, int num_buffers,
 	    !drm_bo_same_page(relocatee->offset, new_cmd_offset)) {
 		drm_bo_kunmap(&relocatee->kmap);
 		relocatee->offset = new_cmd_offset;
+		mutex_lock (&relocatee->buf->mutex);
+		ret = drm_bo_wait (relocatee->buf, 0, 0, FALSE);
+		mutex_unlock (&relocatee->buf->mutex);
+		if (ret) {
+			DRM_ERROR("Could not wait for buffer to apply relocs\n %08lx", new_cmd_offset);
+			return ret;
+		}
 		ret = drm_bo_kmap(relocatee->buf, new_cmd_offset >> PAGE_SHIFT,
 				  1, &relocatee->kmap);
 		if (ret) {