[PATCH] drm/i915: correct the calculation of first_pd_entry_in_global_pt

[xiong.y.zhang at intel.com (Zhang, Xiong Y)]

When ppgtt is enabled, dev_priv->gtt.total has excluded the gtt space occupied by ppgtt table in i915_gem_init_global_gtt() function. So the calculation of first_pd_entry_in_global_pt doesn't need to subtract I915_PPGTT_PD_ENTRIES again. Or else PPGTT directory table will be destroyed by global gtt allocation.

Signed-off-by: Xiong Zhang<xiong.y.zhang at intel.com>

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index ce024bd..3cd48e2 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -258,8 +258,7 @@ static int gen6_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
        /* ppgtt PDEs reside in the global gtt pagetable, which has 512*1024
         * entries. For aliasing ppgtt support we just steal them at the end for
         * now. */
-       first_pd_entry_in_global_pt =
-               gtt_total_entries(dev_priv->gtt) - I915_PPGTT_PD_ENTRIES;
+       first_pd_entry_in_global_pt = gtt_total_entries(dev_priv->gtt);

        if (IS_HASWELL(dev)) {
                ppgtt->pte_encode = hsw_pte_encode;