nb/intel/x4x/gma.c: Probe VGA EDID on DVI-I ports

This allows the use of the native VGA init on boards featuring DVI-I
ports. Digital output is not supported.

Change-Id: I11a4dd68746e06c7e27ecf3e765bdd0d8cf40515
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/20890
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/src/northbridge/intel/x4x/gma.c b/src/northbridge/intel/x4x/gma.c
index e91d778..db96fac 100644
--- a/src/northbridge/intel/x4x/gma.c
+++ b/src/northbridge/intel/x4x/gma.c
@@ -74,6 +74,15 @@
 	u32 pixel_m1 = 1;
 	u32 pixel_m2 = 1;
 
+	u8 vga_gmbus = GMBUS_PORT_VGADDC;
+
+	if (IS_ENABLED(CONFIG_GFX_GMA_ANALOG_I2C_HDMI_B))
+		vga_gmbus = GMBUS_PORT_DPB;
+	else if (IS_ENABLED(CONFIG_GFX_GMA_ANALOG_I2C_HDMI_C))
+		vga_gmbus = GMBUS_PORT_DPC;
+	else if (IS_ENABLED(CONFIG_GFX_GMA_ANALOG_I2C_HDMI_D))
+		vga_gmbus = GMBUS_PORT_DPD;
+
 	vga_gr_write(0x18, 0);
 
 	/* Set up GTT */
@@ -113,7 +122,11 @@
 
 	udelay(1);
 
-	intel_gmbus_read_edid(mmio + GMBUS0, GMBUS_PORT_VGADDC, 0x50, edid_data,
+	/*
+	 * TODO: check if it is actually an analog display.
+	 * No harm is done but the console output could be confusing.
+	 */
+	intel_gmbus_read_edid(mmio + GMBUS0, vga_gmbus, 0x50, edid_data,
 			sizeof(edid_data));
 	intel_gmbus_stop(mmio + GMBUS0);
 	decode_edid(edid_data,