drm/i915/bios: ignore HDMI on port A

BugLink: http://bugs.launchpad.net/bugs/1724783

commit 2ba7d7e0 upstream.

The hardware state readout oopses after several warnings when trying to
use HDMI on port A, if such a combination is configured in VBT. Filter
the combo out already at the VBT parsing phase.

v2: also ignore DVI (Ville)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102889
Cc: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Daniel Drake <dan@reactivated.net>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170921141920.18172-1-jani.nikula@intel.com
(cherry picked from commit d27ffc1d)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

drivers/gpu/drm/i915/intel_bios.c

@@ -957,6 +957,13 @@ static void parse_ddi_port(struct drm_i915_private *dev_priv, enum port port,
 	is_hdmi = is_dvi && (child->common.device_type & DEVICE_TYPE_NOT_HDMI_OUTPUT) == 0;
 	is_edp = is_dp && (child->common.device_type & DEVICE_TYPE_INTERNAL_CONNECTOR);
 
+	if (port == PORT_A && is_dvi) {
+		DRM_DEBUG_KMS("VBT claims port A supports DVI%s, ignoring\n",
+			      is_hdmi ? "/HDMI" : "");
+		is_dvi = false;
+		is_hdmi = false;
+	}
+
 	info->supports_dvi = is_dvi;
 	info->supports_hdmi = is_hdmi;
 	info->supports_dp = is_dp;