1 files changed, 72 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 9564ca44a97..9ab38efffec 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -36,6 +36,7 @@
 #include "intel_drv.h"
 #include "i915_drm.h"
 #include "i915_drv.h"
+#include <linux/acpi.h>
 
 #define I915_LVDS "i915_lvds"
 
@@ -252,14 +253,14 @@ static bool intel_lvds_mode_fixup(struct drm_encoder *encoder,
 
         /* Should never happen!! */
         if (!IS_I965G(dev) && intel_crtc->pipe == 0) {
-                printk(KERN_ERR "Can't support LVDS on pipe A\n");
+                DRM_ERROR("Can't support LVDS on pipe A\n");
                 return false;
         }
 
         /* Should never happen!! */
         list_for_each_entry(tmp_encoder, &dev->mode_config.encoder_list, head) {
                 if (tmp_encoder != encoder && tmp_encoder->crtc == encoder->crtc) {
-                        printk(KERN_ERR "Can't enable LVDS and another "
+                        DRM_ERROR("Can't enable LVDS and another "
                                "encoder on the same pipe\n");
                         return false;
                 }
@@ -788,6 +789,65 @@ 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, &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_lvds_init - setup LVDS connectors on this device
  * @dev: drm device
@@ -811,6 +871,16 @@ void intel_lvds_init(struct drm_device *dev)
         if (dmi_check_system(intel_no_lvds))
                 return;
 
+        /* Assume that any device without an ACPI LID device also doesn't
+         * have an integrated LVDS.  We would be better off parsing the BIOS
+         * to get a reliable indicator, but that code isn't written yet.
+         *
+         * In the case of all-in-one desktops using LVDS that we've seen,
+         * they're using SDVO LVDS.
+         */
+        if (!intel_lid_present())
+                return;
+
         if (IS_IGDNG(dev)) {
                 if ((I915_READ(PCH_LVDS) & LVDS_DETECTED) == 0)
                         return;