nouveau: add optimus detection to DSM code.

optimus has another DSM GUID, so we check for its existance,
also allow the BIOS stuff is we find it.
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/nouveau/nouveau_acpi.c

@@ -37,15 +37,71 @@
 
 static struct nouveau_dsm_priv {
 	bool dsm_detected;
+	bool optimus_detected;
 	acpi_handle dhandle;
 	acpi_handle rom_handle;
 } nouveau_dsm_priv;
 
+#define NOUVEAU_DSM_HAS_MUX 0x1
+#define NOUVEAU_DSM_HAS_OPT 0x2
+
 static const char nouveau_dsm_muid[] = {
 	0xA0, 0xA0, 0x95, 0x9D, 0x60, 0x00, 0x48, 0x4D,
 	0xB3, 0x4D, 0x7E, 0x5F, 0xEA, 0x12, 0x9F, 0xD4,
 };
 
+static const char nouveau_op_dsm_muid[] = {
+	0xF8, 0xD8, 0x86, 0xA4, 0xDA, 0x0B, 0x1B, 0x47,
+	0xA7, 0x2B, 0x60, 0x42, 0xA6, 0xB5, 0xBE, 0xE0,
+};
+
+static int nouveau_optimus_dsm(acpi_handle handle, int func, int arg, uint32_t *result)
+{
+	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
+	struct acpi_object_list input;
+	union acpi_object params[4];
+	union acpi_object *obj;
+	int err;
+
+	input.count = 4;
+	input.pointer = params;
+	params[0].type = ACPI_TYPE_BUFFER;
+	params[0].buffer.length = sizeof(nouveau_op_dsm_muid);
+	params[0].buffer.pointer = (char *)nouveau_op_dsm_muid;
+	params[1].type = ACPI_TYPE_INTEGER;
+	params[1].integer.value = 0x00000100;
+	params[2].type = ACPI_TYPE_INTEGER;
+	params[2].integer.value = func;
+	params[3].type = ACPI_TYPE_BUFFER;
+	params[3].buffer.length = 0;
+
+	err = acpi_evaluate_object(handle, "_DSM", &input, &output);
+	if (err) {
+		printk(KERN_INFO "failed to evaluate _DSM: %d\n", err);
+		return err;
+	}
+
+	obj = (union acpi_object *)output.pointer;
+
+	if (obj->type == ACPI_TYPE_INTEGER)
+		if (obj->integer.value == 0x80000002) {
+			return -ENODEV;
+		}
+
+	if (obj->type == ACPI_TYPE_BUFFER) {
+		if (obj->buffer.length == 4 && result) {
+			*result = 0;
+			*result |= obj->buffer.pointer[0];
+			*result |= (obj->buffer.pointer[1] << 8);
+			*result |= (obj->buffer.pointer[2] << 16);
+			*result |= (obj->buffer.pointer[3] << 24);
+		}
+	}
+
+	kfree(output.pointer);
+	return 0;
+}
+
 static int nouveau_dsm(acpi_handle handle, int func, int arg, uint32_t *result)
 {
 	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
@@ -151,11 +207,11 @@ static struct vga_switcheroo_handler nouveau_dsm_handler = {
 	.get_client_id = nouveau_dsm_get_client_id,
 };
 
-static bool nouveau_dsm_pci_probe(struct pci_dev *pdev)
+static int nouveau_dsm_pci_probe(struct pci_dev *pdev)
 {
 	acpi_handle dhandle, nvidia_handle;
 	acpi_status status;
-	int ret;
+	int ret, retval = 0;
 	uint32_t result;
 
 	dhandle = DEVICE_ACPI_HANDLE(&pdev->dev);
@@ -169,11 +225,17 @@ static bool nouveau_dsm_pci_probe(struct pci_dev *pdev)
 
 	ret = nouveau_dsm(dhandle, NOUVEAU_DSM_SUPPORTED,
 			  NOUVEAU_DSM_SUPPORTED_FUNCTIONS, &result);
-	if (ret < 0)
-		return false;
+	if (ret == 0)
+		retval |= NOUVEAU_DSM_HAS_MUX;
 
-	nouveau_dsm_priv.dhandle = dhandle;
-	return true;
+	ret = nouveau_optimus_dsm(dhandle, 0, 0, &result);
+	if (ret == 0)
+		retval |= NOUVEAU_DSM_HAS_OPT;
+
+	if (retval)
+		nouveau_dsm_priv.dhandle = dhandle;
+
+	return retval;
 }
 
 static bool nouveau_dsm_detect(void)
@@ -182,30 +244,42 @@ static bool nouveau_dsm_detect(void)
 	struct acpi_buffer buffer = {sizeof(acpi_method_name), acpi_method_name};
 	struct pci_dev *pdev = NULL;
 	int has_dsm = 0;
+	int has_optimus;
 	int vga_count = 0;
 	bool guid_valid;
+	int retval;
+	bool ret = false;
 
-	/* lookup the GUID */
+	/* lookup the MXM GUID */
 	guid_valid = mxm_wmi_supported();
-	if (!guid_valid)
-		return false;
 
-	printk("MXM GUID detected in BIOS\n");
+	if (guid_valid)
+		printk("MXM: GUID detected in BIOS\n");
 
+	/* now do DSM detection */
 	while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev)) != NULL) {
 		vga_count++;
 
-		has_dsm |= (nouveau_dsm_pci_probe(pdev) == true);
+		retval = nouveau_dsm_pci_probe(pdev);
+		printk("ret val is %d\n", retval);
+		if (retval & NOUVEAU_DSM_HAS_MUX)
+			has_dsm |= 1;
+		if (retval & NOUVEAU_DSM_HAS_OPT)
+			has_optimus = 1;
 	}
 
-	if (vga_count == 2 && has_dsm) {
+	if (vga_count == 2 && has_dsm && guid_valid) {
 		acpi_get_name(nouveau_dsm_priv.dhandle, ACPI_FULL_PATHNAME, &buffer);
 		printk(KERN_INFO "VGA switcheroo: detected DSM switching method %s handle\n",
 		       acpi_method_name);
 		nouveau_dsm_priv.dsm_detected = true;
-		return true;
+		ret = true;
 	}
-	return false;
+
+	if (has_optimus == 1)
+		nouveau_dsm_priv.optimus_detected = true;
+
+	return ret;
 }
 
 void nouveau_register_dsm_handler(void)
@@ -258,7 +332,7 @@ bool nouveau_acpi_rom_supported(struct pci_dev *pdev)
 	acpi_status status;
 	acpi_handle dhandle, rom_handle;
 
-	if (!nouveau_dsm_priv.dsm_detected)
+	if (!nouveau_dsm_priv.dsm_detected && !nouveau_dsm_priv.optimus_detected)
 		return false;
 
 	dhandle = DEVICE_ACPI_HANDLE(&pdev->dev);