drm/i915: Set up an MTRR covering the GTT at driver load.

[safe/jmp/linux-2.6] / drivers / gpu / drm / i915 / i915_dma.c

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index ee64b73..1e01e78 100644 (file)
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -966,10 +966,6 @@ static int i915_load_modeset_init(struct drm_device *dev)
        if (ret)
                goto kfree_devname;
 
-        dev_priv->mm.gtt_mapping =
-               io_mapping_create_wc(dev->agp->base,
-                                    dev->agp->agp_info.aper_size * 1024*1024);
-
        /* Allow hardware batchbuffers unless told otherwise.
         */
        dev_priv->allow_batchbuffer = 1;
@@ -1081,6 +1077,23 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
                goto free_priv;
        }
 
+        dev_priv->mm.gtt_mapping =
+               io_mapping_create_wc(dev->agp->base,
+                                    dev->agp->agp_info.aper_size * 1024*1024);
+       /* Set up a WC MTRR for non-PAT systems.  This is more common than
+        * one would think, because the kernel disables PAT on first
+        * generation Core chips because WC PAT gets overridden by a UC
+        * MTRR if present.  Even if a UC MTRR isn't present.
+        */
+       dev_priv->mm.gtt_mtrr = mtrr_add(dev->agp->base,
+                                        dev->agp->agp_info.aper_size *
+                                        1024 * 1024,
+                                        MTRR_TYPE_WRCOMB, 1);
+       if (dev_priv->mm.gtt_mtrr < 0) {
+               DRM_INFO("MTRR allocation failed\n.  Graphics "
+                        "performance may suffer.\n");
+       }
+
 #ifdef CONFIG_HIGHMEM64G
        /* don't enable GEM on PAE - needs agp + set_memory_* interface fixes */
        dev_priv->has_gem = 0;
@@ -1145,8 +1158,14 @@ int i915_driver_unload(struct drm_device *dev)
 {
        struct drm_i915_private *dev_priv = dev->dev_private;
 
+       io_mapping_free(dev_priv->mm.gtt_mapping);
+       if (dev_priv->mm.gtt_mtrr >= 0) {
+               mtrr_del(dev_priv->mm.gtt_mtrr, dev->agp->base,
+                        dev->agp->agp_info.aper_size * 1024 * 1024);
+               dev_priv->mm.gtt_mtrr = -1;
+       }
+
        if (drm_core_check_feature(dev, DRIVER_MODESET)) {
-               io_mapping_free(dev_priv->mm.gtt_mapping);
                drm_irq_uninstall(dev);
        }