#define I830_GMCH_MEM_MASK             0x1
 #define I830_GMCH_MEM_64M              0x1
 #define I830_GMCH_MEM_128M             0
-#define I830_GMCH_GMS_MASK             0xF0
+#define I830_GMCH_GMS_MASK             0x70
 #define I830_GMCH_GMS_DISABLED         0x00
 #define I830_GMCH_GMS_LOCAL            0x10
 #define I830_GMCH_GMS_STOLEN_512       0x20
 #define INTEL_I830_ERRSTS      0x92
 
 /* Intel 855GM/852GM registers */
+#define I855_GMCH_GMS_MASK             0xF0
 #define I855_GMCH_GMS_STOLEN_0M                0x0
 #define I855_GMCH_GMS_STOLEN_1M                (0x1 << 4)
 #define I855_GMCH_GMS_STOLEN_4M                (0x2 << 4)
 
                 */
                if (IS_G33)
                        size = 0;
-               switch (gmch_ctrl & I830_GMCH_GMS_MASK) {
+               switch (gmch_ctrl & I855_GMCH_GMS_MASK) {
                case I855_GMCH_GMS_STOLEN_1M:
                        gtt_entries = MB(1) - KB(size);
                        break;