drm/i915: move VBT based LVDS presence check to intel_bios.c
Hide knowledge about VBT child devices in intel_bios.c.
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1458125015-7931-2-git-send-email-jani.nikula@intel.com
diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index d5e6da0..4f7eba3 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -1472,3 +1472,53 @@
return false;
}
+
+/**
+ * intel_bios_is_lvds_present - is LVDS present in VBT
+ * @dev_priv: i915 device instance
+ * @i2c_pin: i2c pin for LVDS if present
+ *
+ * Return true if LVDS is present. If no child devices were parsed from VBT,
+ * assume LVDS is present.
+ */
+bool intel_bios_is_lvds_present(struct drm_i915_private *dev_priv, u8 *i2c_pin)
+{
+ int i;
+
+ if (!dev_priv->vbt.child_dev_num)
+ return true;
+
+ for (i = 0; i < dev_priv->vbt.child_dev_num; i++) {
+ union child_device_config *uchild = dev_priv->vbt.child_dev + i;
+ struct old_child_dev_config *child = &uchild->old;
+
+ /* If the device type is not LFP, continue.
+ * We have to check both the new identifiers as well as the
+ * old for compatibility with some BIOSes.
+ */
+ if (child->device_type != DEVICE_TYPE_INT_LFP &&
+ child->device_type != DEVICE_TYPE_LFP)
+ continue;
+
+ if (intel_gmbus_is_valid_pin(dev_priv, child->i2c_pin))
+ *i2c_pin = child->i2c_pin;
+
+ /* However, we cannot trust the BIOS writers to populate
+ * the VBT correctly. Since LVDS requires additional
+ * information from AIM blocks, a non-zero addin offset is
+ * a good indicator that the LVDS is actually present.
+ */
+ if (child->addin_offset)
+ return true;
+
+ /* But even then some BIOS writers perform some black magic
+ * and instantiate the device without reference to any
+ * additional data. Trust that if the VBT was written into
+ * the OpRegion then they have validated the LVDS's existence.
+ */
+ if (dev_priv->opregion.vbt)
+ return true;
+ }
+
+ return false;
+}