Comment 24 for bug 855124

Well, that pinpoints it entirely on the EDID probe for the HDMI port. So it would appear to be that we valiantly try to read the EDID through a sea of noise.

Just on the off-chance this helps and points us in the right direction, can you try:

diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
index d98cee6..1b14504 100644
--- a/drivers/gpu/drm/i915/intel_i2c.c
+++ b/drivers/gpu/drm/i915/intel_i2c.c
@@ -401,7 +401,7 @@ int intel_setup_gmbus(struct drm_device *dev)
                bus->reg0 = i | GMBUS_RATE_100KHZ;

                /* XXX force bit banging until GMBUS is fully debugged */
- bus->force_bit = intel_gpio_create(dev_priv, i);
+ //bus->force_bit = intel_gpio_create(dev_priv, i);
        }

        intel_i2c_reset(dev_priv->dev);