drm/radeon/kms: check modes against max pixel clock

Filter out modes that are higher than the max pixel
clock.
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

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;
 };
 
 /*

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;
 	}
 

drivers/gpu/drm/radeon/radeon_clocks.c

@@ -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 =

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;

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;
 }