drm/i915/vbt: split out defaults that are set when there is no VBT

The main thing are the DDI ports. If there's a VBT that says there are
no outputs, we should trust that, and not have semi-random
defaults. Unfortunately, the defaults have resulted in some Chromebooks
without VBT to rely on this behaviour, so we split out the defaults for
the missing VBT case.

Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/95c26079ff640d43f53b944f17e9fc356b36daec.1489152288.git.jani.nikula@intel.com

diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 710988d..639d45c 100644 (file)
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -1341,6 +1341,7 @@ parse_device_mapping(struct drm_i915_private *dev_priv,
        return;
 }
 
+/* Common defaults which may be overridden by VBT. */
 static void
 init_vbt_defaults(struct drm_i915_private *dev_priv)
 {
@@ -1377,6 +1378,18 @@ init_vbt_defaults(struct drm_i915_private *dev_priv)
                        &dev_priv->vbt.ddi_port_info[port];
 
                info->hdmi_level_shift = HDMI_LEVEL_SHIFT_UNKNOWN;
+       }
+}
+
+/* Defaults to initialize only if there is no VBT. */
+static void
+init_vbt_missing_defaults(struct drm_i915_private *dev_priv)
+{
+       enum port port;
+
+       for (port = PORT_A; port < I915_MAX_PORTS; port++) {
+               struct ddi_vbt_port_info *info =
+                       &dev_priv->vbt.ddi_port_info[port];
 
                info->supports_dvi = (port != PORT_A && port != PORT_E);
                info->supports_hdmi = info->supports_dvi;
@@ -1516,8 +1529,10 @@ void intel_bios_init(struct drm_i915_private *dev_priv)
        parse_ddi_ports(dev_priv, bdb);
 
 out:
-       if (!vbt)
+       if (!vbt) {
                DRM_INFO("Failed to find VBIOS tables (VBT)\n");
+               init_vbt_missing_defaults(dev_priv);
+       }
 
        if (bios)
                pci_unmap_rom(pdev, bios);