drm/i915: restore gtt on resume in the drm instead of in intel-gtt.ko

This still uses the agp functions to actually reinstate the mappings
(with a gross hack to make agp cooperate), but it wires everything
up correctly for the switchover.

The call to agp_rebind_memory can be dropped because all non-kms drivers
do all their rebinding on EnterVT.

v2: Be more paranoid and flush the chipset cache after restoring gtt
mappings.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
new file mode 100644
index 0000000..5f21d0a
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -0,0 +1,49 @@
+/*
+ * Copyright © 2010 Daniel Vetter
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#include "drmP.h"
+#include "drm.h"
+#include "i915_drm.h"
+#include "i915_drv.h"
+#include "i915_trace.h"
+#include "intel_drv.h"
+
+void i915_gem_restore_gtt_mappings(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_i915_gem_object *obj_priv;
+	int ret;
+
+	list_for_each_entry(obj_priv,
+			    &dev_priv->mm.gtt_list,
+			    gtt_list) {
+		/* Hack to force agp to reinsert buffer object. */
+		obj_priv->agp_mem->is_bound = false;
+		ret = agp_bind_memory(obj_priv->agp_mem, obj_priv->gtt_space->start / PAGE_SIZE);
+		BUG_ON(ret != 0);
+	}
+
+	/* Be paranoid and flush the chipset cache. */
+	intel_gtt_chipset_flush();
+}