drm/i915: Don't check for lid presence when detecting LVDS

Checking for the presence of a lid in order to validate whether or not
an LVDS display exists fails on some development platforms that implement
a lid device but allow the LVDS to be disabled. The VBT is correctly
updated, but Linux assumes that an LVDS is still present and lies to
userspace. Remove the lid check and trust the VBT.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/intel_lvds.c

@@ -854,65 +854,6 @@ static const struct dmi_system_id intel_no_lvds[] = {
 	{ }	/* terminating entry */
 };
 
-#ifdef CONFIG_ACPI
-/*
- * check_lid_device -- check whether @handle is an ACPI LID device.
- * @handle: ACPI device handle
- * @level : depth in the ACPI namespace tree
- * @context: the number of LID device when we find the device
- * @rv: a return value to fill if desired (Not use)
- */
-static acpi_status
-check_lid_device(acpi_handle handle, u32 level, void *context,
-			void **return_value)
-{
-	struct acpi_device *acpi_dev;
-	int *lid_present = context;
-
-	acpi_dev = NULL;
-	/* Get the acpi device for device handle */
-	if (acpi_bus_get_device(handle, &acpi_dev) || !acpi_dev) {
-		/* If there is no ACPI device for handle, return */
-		return AE_OK;
-	}
-
-	if (!strncmp(acpi_device_hid(acpi_dev), "PNP0C0D", 7))
-		*lid_present = 1;
-
-	return AE_OK;
-}
-
-/**
- * check whether there exists the ACPI LID device by enumerating the ACPI
- * device tree.
- */
-static int intel_lid_present(void)
-{
-	int lid_present = 0;
-
-	if (acpi_disabled) {
-		/* If ACPI is disabled, there is no ACPI device tree to
-		 * check, so assume the LID device would have been present.
-		 */
-		return 1;
-	}
-
-	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
-				ACPI_UINT32_MAX,
-				check_lid_device, NULL, &lid_present, NULL);
-
-	return lid_present;
-}
-#else
-static int intel_lid_present(void)
-{
-	/* In the absence of ACPI built in, assume that the LID device would
-	 * have been present.
-	 */
-	return 1;
-}
-#endif
-
 /**
  * intel_find_lvds_downclock - find the reduced downclock for LVDS in EDID
  * @dev: drm device
@@ -1031,12 +972,8 @@ void intel_lvds_init(struct drm_device *dev)
 	if (dmi_check_system(intel_no_lvds))
 		return;
 
-	/*
-	 * Assume LVDS is present if there's an ACPI lid device or if the
-	 * device is present in the VBT.
-	 */
-	if (!lvds_is_present_in_vbt(dev) && !intel_lid_present()) {
-		DRM_DEBUG_KMS("LVDS is not present in VBT and no lid detected\n");
+	if (!lvds_is_present_in_vbt(dev)) {
+		DRM_DEBUG_KMS("LVDS is not present in VBT\n");
 		return;
 	}