diff --git a/drivers/gpu/drm/aspeed/aspeed_gfx.h b/drivers/gpu/drm/aspeed/aspeed_gfx.h
index eb4c267cde5e..c7aefee0657a 100644
--- a/drivers/gpu/drm/aspeed/aspeed_gfx.h
+++ b/drivers/gpu/drm/aspeed/aspeed_gfx.h
@@ -109,11 +109,15 @@ int aspeed_gfx_create_output(struct drm_device *drm);
 #define CRT_THROD_HIGH(x)		((x) << 8)
 
 /* SCU control */
-#define SCU_G6_CLK_COURCE		0x300
+#define G6_CLK_SOURCE			0x300
+#define G6_CLK_SOURCE_MASK		(BIT(8) | BIT(9) | BIT(10))
+#define G6_CLK_SOURCE_HPLL		(BIT(8) | BIT(9) | BIT(10))
+#define G6_CLK_SOURCE_USB		BIT(9)
+#define G6_CLK_SEL3			0x308
+#define G6_CLK_DIV_MASK			0x3F000
+#define G6_CLK_DIV_16			(BIT(16)|BIT(15)|BIT(13)|BIT(12))
+#define G6_USB_40_CLK			BIT(9)
 
 /* GFX FLAGS */
 #define CLK_MASK			BIT(0)
 #define CLK_G6				BIT(0)
-
-#define G6_CLK_MASK			(BIT(8) | BIT(9) | BIT(10))
-#define G6_USB_40_CLK			BIT(9)
diff --git a/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c b/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
index a24fab22eac4..5829be9c7c67 100644
--- a/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
+++ b/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
@@ -23,6 +23,28 @@ drm_pipe_to_aspeed_gfx(struct drm_simple_display_pipe *pipe)
 	return container_of(pipe, struct aspeed_gfx, pipe);
 }
 
+static void aspeed_gfx_set_clock_source(struct aspeed_gfx *priv, int mode_width)
+{
+	regmap_update_bits(priv->scu, G6_CLK_SOURCE, G6_CLK_SOURCE_MASK, 0x0);
+	regmap_update_bits(priv->scu, G6_CLK_SEL3, G6_CLK_DIV_MASK, 0x0);
+
+	switch (mode_width) {
+	case 1024:
+		/* hpll div 16 = 75Mhz */
+		regmap_update_bits(priv->scu, G6_CLK_SOURCE,
+		G6_CLK_SOURCE_MASK, G6_CLK_SOURCE_HPLL);
+		regmap_update_bits(priv->scu, G6_CLK_SEL3,
+		G6_CLK_DIV_MASK, G6_CLK_DIV_16);
+		break;
+	case 800:
+	default:
+		/* usb 40Mhz */
+		regmap_update_bits(priv->scu, G6_CLK_SOURCE,
+		G6_CLK_SOURCE_MASK, G6_CLK_SOURCE_USB);
+		break;
+	}
+}
+
 static int aspeed_gfx_set_pixel_fmt(struct aspeed_gfx *priv, u32 *bpp)
 {
 	struct drm_crtc *crtc = &priv->pipe.crtc;
@@ -77,12 +99,11 @@ static void aspeed_gfx_disable_controller(struct aspeed_gfx *priv)
 	regmap_update_bits(priv->scu, priv->dac_reg, BIT(16), 0);
 }
 
-static void aspeed_gfx_set_clk(struct aspeed_gfx *priv)
+static void aspeed_gfx_set_clk(struct aspeed_gfx *priv, int mode_width)
 {
 	switch (priv->flags & CLK_MASK) {
 	case CLK_G6:
-		regmap_update_bits(priv->scu, SCU_G6_CLK_COURCE, G6_CLK_MASK, 0x0);
-		regmap_update_bits(priv->scu, SCU_G6_CLK_COURCE, G6_CLK_MASK, G6_USB_40_CLK);
+		aspeed_gfx_set_clock_source(priv, mode_width);
 		break;
 	default:
 		break;
@@ -99,7 +120,7 @@ static void aspeed_gfx_crtc_mode_set_nofb(struct aspeed_gfx *priv)
 	if (err)
 		return;
 
-	aspeed_gfx_set_clk(priv);
+	aspeed_gfx_set_clk(priv, m->hdisplay);
 
 #if 0
 	/* TODO: we have only been able to test with the 40MHz USB clock. The
diff --git a/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c b/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
index af56ffdccc65..e1a814aebc2d 100644
--- a/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
+++ b/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
@@ -110,6 +110,7 @@ static const struct drm_mode_config_funcs aspeed_gfx_mode_config_funcs = {
 
 static int aspeed_gfx_setup_mode_config(struct drm_device *drm)
 {
+	struct aspeed_gfx *priv = to_aspeed_gfx(drm);
 	int ret;
 
 	ret = drmm_mode_config_init(drm);
@@ -118,8 +119,18 @@ static int aspeed_gfx_setup_mode_config(struct drm_device *drm)
 
 	drm->mode_config.min_width = 0;
 	drm->mode_config.min_height = 0;
-	drm->mode_config.max_width = 800;
-	drm->mode_config.max_height = 600;
+
+	switch (priv->flags & CLK_MASK) {
+	case CLK_G6:
+		drm->mode_config.max_width = 1024;
+		drm->mode_config.max_height = 768;
+		break;
+	default:
+		drm->mode_config.max_width = 800;
+		drm->mode_config.max_height = 600;
+		break;
+	}
+
 	drm->mode_config.funcs = &aspeed_gfx_mode_config_funcs;
 
 	return ret;
@@ -167,6 +178,7 @@ static int aspeed_gfx_load(struct drm_device *drm)
 	priv->vga_scratch_reg = config->vga_scratch_reg;
 	priv->throd_val = config->throd_val;
 	priv->scan_line_max = config->scan_line_max;
+	priv->flags = config->gfx_flags;
 
 	priv->scu = syscon_regmap_lookup_by_phandle(np, "syscon");
 	if (IS_ERR(priv->scu)) {
diff --git a/drivers/gpu/drm/aspeed/aspeed_gfx_out.c b/drivers/gpu/drm/aspeed/aspeed_gfx_out.c
index 6759cb88415a..5d5e04f15c59 100644
--- a/drivers/gpu/drm/aspeed/aspeed_gfx_out.c
+++ b/drivers/gpu/drm/aspeed/aspeed_gfx_out.c
@@ -10,7 +10,19 @@
 
 static int aspeed_gfx_get_modes(struct drm_connector *connector)
 {
-	return drm_add_modes_noedid(connector, 800, 600);
+	struct aspeed_gfx *priv = container_of(connector, struct aspeed_gfx, connector);
+	int mode_count = 0;
+
+	switch (priv->flags & CLK_MASK) {
+	case CLK_G6:
+		mode_count = drm_add_modes_noedid(connector, 1024, 768);
+		break;
+	default:
+		mode_count = drm_add_modes_noedid(connector, 800, 600);
+		break;
+	}
+
+	return mode_count;
 }
 
 static const struct
