drm/i915/bxt: Broxton DDB is 512 blocks

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Antti Koskipää <antti.koskipaa@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index fa4ccb3..1e25e3e 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2538,6 +2538,7 @@
  */
 
 #define SKL_DDB_SIZE		896	/* in blocks */
+#define BXT_DDB_SIZE		512
 
 static void
 skl_ddb_get_pipe_allocation_limits(struct drm_device *dev,
@@ -2556,7 +2557,10 @@
 		return;
 	}
 
-	ddb_size = SKL_DDB_SIZE;
+	if (IS_BROXTON(dev))
+		ddb_size = BXT_DDB_SIZE;
+	else
+		ddb_size = SKL_DDB_SIZE;
 
 	ddb_size -= 4; /* 4 blocks for bypass path allocation */