Try to read the Data from the SDVO SPD ROM, DDC1, DDC2, DDC3.
Use the new mechanism to detect SDVO card.
---
 drivers/gpu/drm/drm_edid.c        |    6 ++
 drivers/gpu/drm/i915/intel_sdvo.c |   88 ++++++++++++++++++++++++++++++++++----
 2 files changed, 87 insertions(+), 7 deletions(-)

Index: linux-2.6.32-rc4/drivers/gpu/drm/i915/intel_sdvo.c
===================================================================
--- linux-2.6.32-rc4.orig/drivers/gpu/drm/i915/intel_sdvo.c	2009-10-14 11:40:33.000000000 +0800
+++ linux-2.6.32-rc4/drivers/gpu/drm/i915/intel_sdvo.c	2009-10-16 10:04:48.000000000 +0800
@@ -47,7 +47,7 @@
 	"SECAM_K"  , "SECAM_K1", "SECAM_L" ,
 	"SECAM_60"
 };
-
+u8 spd_buffer[256];
 #define TV_FORMAT_NUM  (sizeof(tv_format_names) / sizeof(*tv_format_names))
 
 struct intel_sdvo_priv {
@@ -2666,6 +2666,19 @@
 	return;
 }
 
+static void sdvo_print_spd()
+{
+	int i;
+	printk(KERN_DEBUG "SPD ROM");
+	for (i = 0; i < 256; i++) {
+		if (i % 16 ==0)
+			printk("\n\t%x, ", spd_buffer[i]);
+		else
+			printk("%x ", spd_buffer[i]);
+	}
+	printk(KERN_DEBUG "End SPD ROM\n");
+	return;
+}
 bool intel_sdvo_init(struct drm_device *dev, int output_device)
 {
 	struct drm_connector *connector;
@@ -2699,16 +2712,79 @@
 
 	/* Save the bit-banging i2c functionality for use by the DDC wrapper */
 	intel_sdvo_i2c_bit_algo.functionality = intel_output->i2c_bus->algo->functionality;
-
+	if (output_device == SDVOB)
+	{
+		u8 out_buf;
+		struct i2c_msg temp_msgs[] = {
+			{
+			.addr = DDC_ADDR,
+			.flags = 0,
+			.len = 1,
+			.buf = &out_buf,
+			},
+			{
+			.addr = DDC_ADDR,
+			.flags = I2C_M_RD,
+			.len = 128,
+			.buf = spd_buffer,
+			},
+		};
+		out_buf = 0;
+		/* switch to SPD DDC */
+		printk(KERN_DEBUG "Switch to SDVO SPD ROM\n");
+		intel_sdvo_set_control_bus_switch(intel_output, 1);
+		if (i2c_transfer(intel_output->i2c_bus, temp_msgs, 2) == 2) {
+			sdvo_print_spd();
+		} else {
+			printk(KERN_DEBUG "Can't read the SDVO SPD ROM\n");
+		}
+		/* switch to SDVO DDC1 */
+		printk(KERN_DEBUG "Switch to SDVO DDC1\n");
+		intel_sdvo_set_control_bus_switch(intel_output, 2);
+		if (i2c_transfer(intel_output->i2c_bus, temp_msgs, 2) == 2) {
+			sdvo_print_spd();
+		} else {
+			printk(KERN_DEBUG "Can't read the SDVO DDC1\n");
+		}
+		/* switch to SPD DDC2 */
+		printk(KERN_DEBUG "Switch to SDVO DDC2\n");
+		intel_sdvo_set_control_bus_switch(intel_output, 4);
+		if (i2c_transfer(intel_output->i2c_bus, temp_msgs, 2) == 2) {
+			sdvo_print_spd();
+		} else {
+			printk(KERN_DEBUG "Can't read the SDVO DDC2\n");
+		}
+		/* switch to SPD DDC3 */
+		printk(KERN_DEBUG "Switch to SDVO DDC3\n");
+		intel_sdvo_set_control_bus_switch(intel_output, 8);
+		if (i2c_transfer(intel_output->i2c_bus, temp_msgs, 2) == 2) {
+			sdvo_print_spd();
+		} else {
+			printk(KERN_DEBUG "Can't read the SDVO DDC3\n");
+		}
+	}
 	/* Read the regs to test if we can talk to the device */
+	/* At the same time it is also used to switch the SDVO device from
+	 * PROM to SDVO-only state.
+	 * when it fails, we will contine to check whether the capibility
+	 * is detected.
+	 */
 	for (i = 0; i < 0x40; i++) {
 		if (!intel_sdvo_read_byte(intel_output, i, &ch[i])) {
-			DRM_DEBUG_KMS("No SDVO device found on SDVO%c\n",
+			DRM_DEBUG_KMS("Failure in state transistion on SDVO%c\n",
 					output_device == SDVOB ? 'B' : 'C');
-			goto err_i2c;
+			break;
 		}
 	}
-
+	/*
+	 * According to the SDVO spec, the capability is mandatory. The
+	 * failure indicates that no SDVO device is detected.
+	 */
+	if (!intel_sdvo_get_capabilities(intel_output, &sdvo_priv->caps)) {
+		DRM_DEBUG_KMS("No SDVO device found on SDVO%c\n",
+				output_device == SDVOB ? 'B' : 'C');
+		goto err_i2c;
+	}
 	/* setup the DDC bus. */
 	if (output_device == SDVOB) {
 		intel_output->ddc_bus = intel_i2c_create(dev, GPIOE, "SDVOB DDC BUS");
@@ -2726,8 +2802,6 @@
 	/* Wrap with our custom algo which switches to DDC mode */
 	intel_output->ddc_bus->algo = &intel_sdvo_i2c_bit_algo;
 
-	/* In defaut case sdvo lvds is false */
-	intel_sdvo_get_capabilities(intel_output, &sdvo_priv->caps);
 
 	if (intel_sdvo_output_setup(intel_output,
 				    sdvo_priv->caps.output_flags) != true) {
Index: linux-2.6.32-rc4/drivers/gpu/drm/drm_edid.c
===================================================================
--- linux-2.6.32-rc4.orig/drivers/gpu/drm/drm_edid.c	2009-10-14 11:40:33.000000000 +0800
+++ linux-2.6.32-rc4/drivers/gpu/drm/drm_edid.c	2009-10-14 11:42:40.000000000 +0800
@@ -1057,6 +1057,12 @@
 		ret = -1;
 	}
 end:
+	printk(KERN_DEBUG "Read EDID for connector %s, DDC bus name %s\n",
+			drm_get_connector_name(connector), adapter->name);
+	if (ret)
+		printk(KERN_DEBUG "Incorrect EDID\n");
+	else
+		printk(KERN_DEBUG "EDID is obtained\n");
 	return ret;
 }