drm/i915: Check the LID device to decide whether the LVDS should be initialized

[deliverable/linux.git] / drivers / gpu / drm / i915 / intel_lvds.c

diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index f65044b1647b2b24fb84a466ec260216ab54b731..9ab38efffecfeab426e48c45bbc3a7ee77bf96f4 100644 (file)
--- 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"
 
@@ -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;