drm/i915, agp/intel: Fix stolen memory size on Sandybridge

New memory control config reg at 0x50 should be used for stolen
memory size detection on Sandybridge.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 2a312b6..3d59862 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -53,6 +53,25 @@
 #define INTEL_GMCH_GMS_STOLEN_224M	(0xc << 4)
 #define INTEL_GMCH_GMS_STOLEN_352M	(0xd << 4)
 
+#define SNB_GMCH_CTRL	0x50
+#define SNB_GMCH_GMS_STOLEN_MASK	0xF8
+#define SNB_GMCH_GMS_STOLEN_32M		(1 << 3)
+#define SNB_GMCH_GMS_STOLEN_64M		(2 << 3)
+#define SNB_GMCH_GMS_STOLEN_96M		(3 << 3)
+#define SNB_GMCH_GMS_STOLEN_128M	(4 << 3)
+#define SNB_GMCH_GMS_STOLEN_160M	(5 << 3)
+#define SNB_GMCH_GMS_STOLEN_192M	(6 << 3)
+#define SNB_GMCH_GMS_STOLEN_224M	(7 << 3)
+#define SNB_GMCH_GMS_STOLEN_256M	(8 << 3)
+#define SNB_GMCH_GMS_STOLEN_288M	(9 << 3)
+#define SNB_GMCH_GMS_STOLEN_320M	(0xa << 3)
+#define SNB_GMCH_GMS_STOLEN_352M	(0xb << 3)
+#define SNB_GMCH_GMS_STOLEN_384M	(0xc << 3)
+#define SNB_GMCH_GMS_STOLEN_416M	(0xd << 3)
+#define SNB_GMCH_GMS_STOLEN_448M	(0xe << 3)
+#define SNB_GMCH_GMS_STOLEN_480M	(0xf << 3)
+#define SNB_GMCH_GMS_STOLEN_512M	(0x10 << 3)
+
 /* PCI config space */
 
 #define HPLLCC	0xc0 /* 855 only */