diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c
index 979a0241fdcb..c17cf611625c 100644
--- a/drivers/gpu/drm/i915/display/intel_cdclk.c
+++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
@@ -2705,8 +2705,13 @@ static int g4x_hrawclk(struct drm_i915_private *dev_priv)
 	u32 clkcfg;
 
 	/* hrawclock is 1/4 the FSB frequency */
-	clkcfg = intel_de_read(dev_priv, CLKCFG);
-	switch (clkcfg & CLKCFG_FSB_MASK) {
+	clkcfg = intel_de_read(dev_priv, CLKCFG) & CLKCFG_FSB_MASK;
+
+	/* ELK seems to redefine some of the values */
+	if (IS_G45(dev_priv) && clkcfg == CLKCFG_FSB_1600_ALT)
+		return 400000;
+
+	switch (clkcfg) {
 	case CLKCFG_FSB_400:
 		return 100000;
 	case CLKCFG_FSB_533:
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 6c076a24eb82..10187780e06c 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3775,12 +3775,8 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
 #define CLKCFG_FSB_1067					(6 << 0)	/* hrawclk 266 */
 #define CLKCFG_FSB_1067_ALT				(0 << 0)	/* hrawclk 266 */
 #define CLKCFG_FSB_1333					(7 << 0)	/* hrawclk 333 */
-/*
- * Note that on at least on ELK the below value is reported for both
- * 333 and 400 MHz BIOS FSB setting, but given that the gmch datasheet
- * lists only 200/266/333 MHz FSB as supported let's decode it as 333 MHz.
- */
 #define CLKCFG_FSB_1333_ALT				(4 << 0)	/* hrawclk 333 */
+#define CLKCFG_FSB_1600_ALT				(6 << 0)	/* hrawclk 400 */
 #define CLKCFG_FSB_MASK					(7 << 0)
 #define CLKCFG_MEM_533					(1 << 4)
 #define CLKCFG_MEM_667					(2 << 4)