1 files changed, 11 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 051134c56ae..53d54455262 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1011,8 +1011,16 @@ static int i915_load_modeset_init(struct drm_device *dev)
         /* Basic memrange allocator for stolen space (aka vram) */
         drm_mm_init(&dev_priv->vram, 0, prealloc_size);
 
-        /* Let GEM Manage from end of prealloc space to end of aperture */
-        i915_gem_do_init(dev, prealloc_size, agp_size);
+        /* Let GEM Manage from end of prealloc space to end of aperture.
+         *
+         * However, leave one page at the end still bound to the scratch page.
+         * There are a number of places where the hardware apparently
+         * prefetches past the end of the object, and we've seen multiple
+         * hangs with the GPU head pointer stuck in a batchbuffer bound
+         * at the last page of the aperture.  One page should be enough to
+         * keep any prefetching inside of the aperture.
+         */
+        i915_gem_do_init(dev, prealloc_size, agp_size - 4096);
 
         ret = i915_gem_init_ringbuffer(dev);
         if (ret)
@@ -1350,6 +1358,7 @@ struct drm_ioctl_desc i915_ioctls[] = {
         DRM_IOCTL_DEF(DRM_I915_GEM_SET_TILING, i915_gem_set_tiling, 0),
         DRM_IOCTL_DEF(DRM_I915_GEM_GET_TILING, i915_gem_get_tiling, 0),
         DRM_IOCTL_DEF(DRM_I915_GEM_GET_APERTURE, i915_gem_get_aperture_ioctl, 0),
+        DRM_IOCTL_DEF(DRM_I915_GET_PIPE_FROM_CRTC_ID, intel_get_pipe_from_crtc_id, 0),
 };
 
 int i915_max_ioctl = DRM_ARRAY_SIZE(i915_ioctls);