diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index ba643b57605..27f45579e64 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -165,6 +165,7 @@ struct radeon_clock {
 	uint32_t default_sclk;
 	uint32_t default_dispclk;
 	uint32_t dp_extclk;
+	uint32_t max_pixel_clock;
 };
 
 /*
diff --git a/drivers/gpu/drm/radeon/radeon_atombios.c b/drivers/gpu/drm/radeon/radeon_atombios.c
index 90dfb2b8cf0..fa62a503ae7 100644
--- a/drivers/gpu/drm/radeon/radeon_atombios.c
+++ b/drivers/gpu/drm/radeon/radeon_atombios.c
@@ -1246,6 +1246,10 @@ bool radeon_atom_get_clock_info(struct drm_device *dev)
 		}
 		*dcpll = *p1pll;
 
+		rdev->clock.max_pixel_clock = le16_to_cpu(firmware_info->info.usMaxPixelClock);
+		if (rdev->clock.max_pixel_clock == 0)
+			rdev->clock.max_pixel_clock = 40000;
+
 		return true;
 	}
 
diff --git a/drivers/gpu/drm/radeon/radeon_clocks.c b/drivers/gpu/drm/radeon/radeon_clocks.c
index 5249af8931e..2d48e7a1474 100644
--- a/drivers/gpu/drm/radeon/radeon_clocks.c
+++ b/drivers/gpu/drm/radeon/radeon_clocks.c
@@ -117,7 +117,7 @@ static bool __devinit radeon_read_clocks_OF(struct drm_device *dev)
 	p1pll->reference_div = RREG32_PLL(RADEON_PPLL_REF_DIV) & 0x3ff;
 	if (p1pll->reference_div < 2)
 		p1pll->reference_div = 12;
-	p2pll->reference_div = p1pll->reference_div;	
+	p2pll->reference_div = p1pll->reference_div;
 
 	/* These aren't in the device-tree */
 	if (rdev->family >= CHIP_R420) {
@@ -139,6 +139,8 @@ static bool __devinit radeon_read_clocks_OF(struct drm_device *dev)
 		p2pll->pll_out_min = 12500;
 		p2pll->pll_out_max = 35000;
 	}
+	/* not sure what the max should be in all cases */
+	rdev->clock.max_pixel_clock = 35000;
 
 	spll->reference_freq = mpll->reference_freq = p1pll->reference_freq;
 	spll->reference_div = mpll->reference_div =
@@ -151,7 +153,7 @@ static bool __devinit radeon_read_clocks_OF(struct drm_device *dev)
 	else
 		rdev->clock.default_sclk =
 			radeon_legacy_get_engine_clock(rdev);
-			
+
 	val = of_get_property(dp, "ATY,MCLK", NULL);
 	if (val && *val)
 		rdev->clock.default_mclk = (*val) / 10;
@@ -160,7 +162,7 @@ static bool __devinit radeon_read_clocks_OF(struct drm_device *dev)
 			radeon_legacy_get_memory_clock(rdev);
 
 	DRM_INFO("Using device-tree clock info\n");
-	
+
 	return true;
 }
 #else
diff --git a/drivers/gpu/drm/radeon/radeon_combios.c b/drivers/gpu/drm/radeon/radeon_combios.c
index 5b991f7c6e2..d1b95b70af6 100644
--- a/drivers/gpu/drm/radeon/radeon_combios.c
+++ b/drivers/gpu/drm/radeon/radeon_combios.c
@@ -866,6 +866,11 @@ bool radeon_combios_get_clock_info(struct drm_device *dev)
 		rdev->clock.default_sclk = sclk;
 		rdev->clock.default_mclk = mclk;
 
+		if (RBIOS32(pll_info + 0x16))
+			rdev->clock.max_pixel_clock = RBIOS32(pll_info + 0x16);
+		else
+			rdev->clock.max_pixel_clock = 35000; /* might need something asic specific */
+
 		return true;
 	}
 	return false;
diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c
index ee1dccb3fec..9c2929c7e79 100644
--- a/drivers/gpu/drm/radeon/radeon_connectors.c
+++ b/drivers/gpu/drm/radeon/radeon_connectors.c
@@ -626,8 +626,14 @@ static int radeon_vga_get_modes(struct drm_connector *connector)
 static int radeon_vga_mode_valid(struct drm_connector *connector,
 				  struct drm_display_mode *mode)
 {
+	struct drm_device *dev = connector->dev;
+	struct radeon_device *rdev = dev->dev_private;
+
 	/* XXX check mode bandwidth */
-	/* XXX verify against max DAC output frequency */
+
+	if ((mode->clock / 10) > rdev->clock.max_pixel_clock)
+		return MODE_CLOCK_HIGH;
+
 	return MODE_OK;
 }
 
@@ -1015,6 +1021,11 @@ static int radeon_dvi_mode_valid(struct drm_connector *connector,
 		} else
 			return MODE_CLOCK_HIGH;
 	}
+
+	/* check against the max pixel clock */
+	if ((mode->clock / 10) > rdev->clock.max_pixel_clock)
+		return MODE_CLOCK_HIGH;
+
 	return MODE_OK;
 }