drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright 2012 Advanced Micro Devices, Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  * OTHER DEALINGS IN THE SOFTWARE.
  *
  */

 #include <linux/pci.h>
 #include <linux/acpi.h>
 #include <linux/slab.h>
 #include <linux/power_supply.h>
 #include <acpi/video.h>
 #include <drm/drmP.h>
 #include <drm/drm_crtc_helper.h>
 #include "amdgpu.h"
 #include "amd_acpi.h"
 #include "atom.h"

 extern void amdgpu_pm_acpi_event_handler(struct amdgpu_device *adev);
 /* Call the ATIF method
  */
 /**
  * amdgpu_atif_call - call an ATIF method
  *
  * @handle: acpi handle
  * @function: the ATIF function to execute
  * @params: ATIF function params
  *
  * Executes the requested ATIF function (all asics).
  * Returns a pointer to the acpi output buffer.
  */
 static union acpi_object *amdgpu_atif_call(acpi_handle handle, int function,
 		struct acpi_buffer *params)
 {
 	acpi_status status;
 	union acpi_object atif_arg_elements[2];
 	struct acpi_object_list atif_arg;
 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };

 	atif_arg.count = 2;
 	atif_arg.pointer = &atif_arg_elements[0];

 	atif_arg_elements[0].type = ACPI_TYPE_INTEGER;
 	atif_arg_elements[0].integer.value = function;

 	if (params) {
 		atif_arg_elements[1].type = ACPI_TYPE_BUFFER;
 		atif_arg_elements[1].buffer.length = params->length;
 		atif_arg_elements[1].buffer.pointer = params->pointer;
 	} else {
 		/* We need a second fake parameter */
 		atif_arg_elements[1].type = ACPI_TYPE_INTEGER;
 		atif_arg_elements[1].integer.value = 0;
 	}

 	status = acpi_evaluate_object(handle, "ATIF", &atif_arg, &buffer);

 	/* Fail only if calling the method fails and ATIF is supported */
 	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 		DRM_DEBUG_DRIVER("failed to evaluate ATIF got %s\n",
 				 acpi_format_exception(status));
 		kfree(buffer.pointer);
 		return NULL;
 	}

 	return buffer.pointer;
 }

 /**
  * amdgpu_atif_parse_notification - parse supported notifications
  *
  * @n: supported notifications struct
  * @mask: supported notifications mask from ATIF
  *
  * Use the supported notifications mask from ATIF function
  * ATIF_FUNCTION_VERIFY_INTERFACE to determine what notifications
  * are supported (all asics).
  */
 static void amdgpu_atif_parse_notification(struct amdgpu_atif_notifications *n, u32 mask)
 {
 	n->display_switch = mask & ATIF_DISPLAY_SWITCH_REQUEST_SUPPORTED;
 	n->expansion_mode_change = mask & ATIF_EXPANSION_MODE_CHANGE_REQUEST_SUPPORTED;
 	n->thermal_state = mask & ATIF_THERMAL_STATE_CHANGE_REQUEST_SUPPORTED;
 	n->forced_power_state = mask & ATIF_FORCED_POWER_STATE_CHANGE_REQUEST_SUPPORTED;
 	n->system_power_state = mask & ATIF_SYSTEM_POWER_SOURCE_CHANGE_REQUEST_SUPPORTED;
 	n->display_conf_change = mask & ATIF_DISPLAY_CONF_CHANGE_REQUEST_SUPPORTED;
 	n->px_gfx_switch = mask & ATIF_PX_GFX_SWITCH_REQUEST_SUPPORTED;
 	n->brightness_change = mask & ATIF_PANEL_BRIGHTNESS_CHANGE_REQUEST_SUPPORTED;
 	n->dgpu_display_event = mask & ATIF_DGPU_DISPLAY_EVENT_SUPPORTED;
 }

 /**
  * amdgpu_atif_parse_functions - parse supported functions
  *
  * @f: supported functions struct
  * @mask: supported functions mask from ATIF
  *
  * Use the supported functions mask from ATIF function
  * ATIF_FUNCTION_VERIFY_INTERFACE to determine what functions
  * are supported (all asics).
  */
 static void amdgpu_atif_parse_functions(struct amdgpu_atif_functions *f, u32 mask)
 {
 	f->system_params = mask & ATIF_GET_SYSTEM_PARAMETERS_SUPPORTED;
 	f->sbios_requests = mask & ATIF_GET_SYSTEM_BIOS_REQUESTS_SUPPORTED;
 	f->select_active_disp = mask & ATIF_SELECT_ACTIVE_DISPLAYS_SUPPORTED;
 	f->lid_state = mask & ATIF_GET_LID_STATE_SUPPORTED;
 	f->get_tv_standard = mask & ATIF_GET_TV_STANDARD_FROM_CMOS_SUPPORTED;
 	f->set_tv_standard = mask & ATIF_SET_TV_STANDARD_IN_CMOS_SUPPORTED;
 	f->get_panel_expansion_mode = mask & ATIF_GET_PANEL_EXPANSION_MODE_FROM_CMOS_SUPPORTED;
 	f->set_panel_expansion_mode = mask & ATIF_SET_PANEL_EXPANSION_MODE_IN_CMOS_SUPPORTED;
 	f->temperature_change = mask & ATIF_TEMPERATURE_CHANGE_NOTIFICATION_SUPPORTED;
 	f->graphics_device_types = mask & ATIF_GET_GRAPHICS_DEVICE_TYPES_SUPPORTED;
 }

 /**
  * amdgpu_atif_verify_interface - verify ATIF
  *
  * @handle: acpi handle
  * @atif: amdgpu atif struct
  *
  * Execute the ATIF_FUNCTION_VERIFY_INTERFACE ATIF function
  * to initialize ATIF and determine what features are supported
  * (all asics).
  * returns 0 on success, error on failure.
  */
 static int amdgpu_atif_verify_interface(acpi_handle handle,
 		struct amdgpu_atif *atif)
 {
 	union acpi_object *info;
 	struct atif_verify_interface output;
 	size_t size;
 	int err = 0;

 	info = amdgpu_atif_call(handle, ATIF_FUNCTION_VERIFY_INTERFACE, NULL);
 	if (!info)
 		return -EIO;

 	memset(&output, 0, sizeof(output));

 	size = *(u16 *) info->buffer.pointer;
 	if (size < 12) {
 		DRM_INFO("ATIF buffer is too small: %zu\n", size);
 		err = -EINVAL;
 		goto out;
 	}
 	size = min(sizeof(output), size);

 	memcpy(&output, info->buffer.pointer, size);

 	/* TODO: check version? */
 	DRM_DEBUG_DRIVER("ATIF version %u\n", output.version);

 	amdgpu_atif_parse_notification(&atif->notifications, output.notification_mask);
 	amdgpu_atif_parse_functions(&atif->functions, output.function_bits);

 out:
 	kfree(info);
 	return err;
 }

 /**
  * amdgpu_atif_get_notification_params - determine notify configuration
  *
  * @handle: acpi handle
  * @n: atif notification configuration struct
  *
  * Execute the ATIF_FUNCTION_GET_SYSTEM_PARAMETERS ATIF function
  * to determine if a notifier is used and if so which one
  * (all asics).  This is either Notify(VGA, 0x81) or Notify(VGA, n)
  * where n is specified in the result if a notifier is used.
  * Returns 0 on success, error on failure.
  */
 static int amdgpu_atif_get_notification_params(acpi_handle handle,
 		struct amdgpu_atif_notification_cfg *n)
 {
 	union acpi_object *info;
 	struct atif_system_params params;
 	size_t size;
 	int err = 0;

 	info = amdgpu_atif_call(handle, ATIF_FUNCTION_GET_SYSTEM_PARAMETERS, NULL);
 	if (!info) {
 		err = -EIO;
 		goto out;
 	}

 	size = *(u16 *) info->buffer.pointer;
 	if (size < 10) {
 		err = -EINVAL;
 		goto out;
 	}

 	memset(&params, 0, sizeof(params));
 	size = min(sizeof(params), size);
 	memcpy(&params, info->buffer.pointer, size);

 	DRM_DEBUG_DRIVER("SYSTEM_PARAMS: mask = %#x, flags = %#x\n",
 			params.flags, params.valid_mask);
 	params.flags = params.flags & params.valid_mask;

 	if ((params.flags & ATIF_NOTIFY_MASK) == ATIF_NOTIFY_NONE) {
 		n->enabled = false;
 		n->command_code = 0;
 	} else if ((params.flags & ATIF_NOTIFY_MASK) == ATIF_NOTIFY_81) {
 		n->enabled = true;
 		n->command_code = 0x81;
 	} else {
 		if (size < 11) {
 			err = -EINVAL;
 			goto out;
 		}
 		n->enabled = true;
 		n->command_code = params.command_code;
 	}

 out:
 	DRM_DEBUG_DRIVER("Notification %s, command code = %#x\n",
 			(n->enabled ? "enabled" : "disabled"),
 			n->command_code);
 	kfree(info);
 	return err;
 }

 /**
  * amdgpu_atif_get_sbios_requests - get requested sbios event
  *
  * @handle: acpi handle
  * @req: atif sbios request struct
  *
  * Execute the ATIF_FUNCTION_GET_SYSTEM_BIOS_REQUESTS ATIF function
  * to determine what requests the sbios is making to the driver
  * (all asics).
  * Returns 0 on success, error on failure.
  */
 static int amdgpu_atif_get_sbios_requests(acpi_handle handle,
 		struct atif_sbios_requests *req)
 {
 	union acpi_object *info;
 	size_t size;
 	int count = 0;

 	info = amdgpu_atif_call(handle, ATIF_FUNCTION_GET_SYSTEM_BIOS_REQUESTS, NULL);
 	if (!info)
 		return -EIO;

 	size = *(u16 *)info->buffer.pointer;
 	if (size < 0xd) {
 		count = -EINVAL;
 		goto out;
 	}
 	memset(req, 0, sizeof(*req));

 	size = min(sizeof(*req), size);
 	memcpy(req, info->buffer.pointer, size);
 	DRM_DEBUG_DRIVER("SBIOS pending requests: %#x\n", req->pending);

 	count = hweight32(req->pending);

 out:
 	kfree(info);
 	return count;
 }

 /**
  * amdgpu_atif_handler - handle ATIF notify requests
  *
  * @adev: amdgpu_device pointer
  * @event: atif sbios request struct
  *
  * Checks the acpi event and if it matches an atif event,
  * handles it.
  * Returns NOTIFY code
  */
 int amdgpu_atif_handler(struct amdgpu_device *adev,
 			struct acpi_bus_event *event)
 {
 	struct amdgpu_atif *atif = &adev->atif;
 	struct atif_sbios_requests req;
 	acpi_handle handle;
 	int count;

 	DRM_DEBUG_DRIVER("event, device_class = %s, type = %#x\n",
 			event->device_class, event->type);

 	if (strcmp(event->device_class, ACPI_VIDEO_CLASS) != 0)
 		return NOTIFY_DONE;

 	if (!atif->notification_cfg.enabled ||
 	    event->type != atif->notification_cfg.command_code)
 		/* Not our event */
 		return NOTIFY_DONE;

 	/* Check pending SBIOS requests */
 	handle = ACPI_HANDLE(&adev->pdev->dev);
 	count = amdgpu_atif_get_sbios_requests(handle, &req);

 	if (count <= 0)
 		return NOTIFY_DONE;

 	DRM_DEBUG_DRIVER("ATIF: %d pending SBIOS requests\n", count);

 	if (req.pending & ATIF_PANEL_BRIGHTNESS_CHANGE_REQUEST) {
 		struct amdgpu_encoder *enc = atif->encoder_for_bl;

 		if (enc) {
 			struct amdgpu_encoder_atom_dig *dig = enc->enc_priv;

 			DRM_DEBUG_DRIVER("Changing brightness to %d\n",
 					req.backlight_level);

 			amdgpu_display_backlight_set_level(adev, enc, req.backlight_level);

 #if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) || defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
 			backlight_force_update(dig->bl_dev,
 					       BACKLIGHT_UPDATE_HOTKEY);
 #endif
 		}
 	}
 	/* TODO: check other events */

 	/* We've handled the event, stop the notifier chain. The ACPI interface
 	 * overloads ACPI_VIDEO_NOTIFY_PROBE, we don't want to send that to
 	 * userspace if the event was generated only to signal a SBIOS
 	 * request.
 	 */
 	return NOTIFY_BAD;
 }

 /* Call the ATCS method
  */
 /**
  * amdgpu_atcs_call - call an ATCS method
  *
  * @handle: acpi handle
  * @function: the ATCS function to execute
  * @params: ATCS function params
  *
  * Executes the requested ATCS function (all asics).
  * Returns a pointer to the acpi output buffer.
  */
 static union acpi_object *amdgpu_atcs_call(acpi_handle handle, int function,
 					   struct acpi_buffer *params)
 {
 	acpi_status status;
 	union acpi_object atcs_arg_elements[2];
 	struct acpi_object_list atcs_arg;
 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };

 	atcs_arg.count = 2;
 	atcs_arg.pointer = &atcs_arg_elements[0];

 	atcs_arg_elements[0].type = ACPI_TYPE_INTEGER;
 	atcs_arg_elements[0].integer.value = function;

 	if (params) {
 		atcs_arg_elements[1].type = ACPI_TYPE_BUFFER;
 		atcs_arg_elements[1].buffer.length = params->length;
 		atcs_arg_elements[1].buffer.pointer = params->pointer;
 	} else {
 		/* We need a second fake parameter */
 		atcs_arg_elements[1].type = ACPI_TYPE_INTEGER;
 		atcs_arg_elements[1].integer.value = 0;
 	}

 	status = acpi_evaluate_object(handle, "ATCS", &atcs_arg, &buffer);

 	/* Fail only if calling the method fails and ATIF is supported */
 	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 		DRM_DEBUG_DRIVER("failed to evaluate ATCS got %s\n",
 				 acpi_format_exception(status));
 		kfree(buffer.pointer);
 		return NULL;
 	}

 	return buffer.pointer;
 }

 /**
  * amdgpu_atcs_parse_functions - parse supported functions
  *
  * @f: supported functions struct
  * @mask: supported functions mask from ATCS
  *
  * Use the supported functions mask from ATCS function
  * ATCS_FUNCTION_VERIFY_INTERFACE to determine what functions
  * are supported (all asics).
  */
 static void amdgpu_atcs_parse_functions(struct amdgpu_atcs_functions *f, u32 mask)
 {
 	f->get_ext_state = mask & ATCS_GET_EXTERNAL_STATE_SUPPORTED;
 	f->pcie_perf_req = mask & ATCS_PCIE_PERFORMANCE_REQUEST_SUPPORTED;
 	f->pcie_dev_rdy = mask & ATCS_PCIE_DEVICE_READY_NOTIFICATION_SUPPORTED;
 	f->pcie_bus_width = mask & ATCS_SET_PCIE_BUS_WIDTH_SUPPORTED;
 }

 /**
  * amdgpu_atcs_verify_interface - verify ATCS
  *
  * @handle: acpi handle
  * @atcs: amdgpu atcs struct
  *
  * Execute the ATCS_FUNCTION_VERIFY_INTERFACE ATCS function
  * to initialize ATCS and determine what features are supported
  * (all asics).
  * returns 0 on success, error on failure.
  */
 static int amdgpu_atcs_verify_interface(acpi_handle handle,
 					struct amdgpu_atcs *atcs)
 {
 	union acpi_object *info;
 	struct atcs_verify_interface output;
 	size_t size;
 	int err = 0;

 	info = amdgpu_atcs_call(handle, ATCS_FUNCTION_VERIFY_INTERFACE, NULL);
 	if (!info)
 		return -EIO;

 	memset(&output, 0, sizeof(output));

 	size = *(u16 *) info->buffer.pointer;
 	if (size < 8) {
 		DRM_INFO("ATCS buffer is too small: %zu\n", size);
 		err = -EINVAL;
 		goto out;
 	}
 	size = min(sizeof(output), size);

 	memcpy(&output, info->buffer.pointer, size);

 	/* TODO: check version? */
 	DRM_DEBUG_DRIVER("ATCS version %u\n", output.version);

 	amdgpu_atcs_parse_functions(&atcs->functions, output.function_bits);

 out:
 	kfree(info);
 	return err;
 }

 /**
  * amdgpu_acpi_is_pcie_performance_request_supported
  *
  * @adev: amdgpu_device pointer
  *
  * Check if the ATCS pcie_perf_req and pcie_dev_rdy methods
  * are supported (all asics).
  * returns true if supported, false if not.
  */
 bool amdgpu_acpi_is_pcie_performance_request_supported(struct amdgpu_device *adev)
 {
 	struct amdgpu_atcs *atcs = &adev->atcs;

 	if (atcs->functions.pcie_perf_req && atcs->functions.pcie_dev_rdy)
 		return true;

 	return false;
 }

 /**
  * amdgpu_acpi_pcie_notify_device_ready
  *
  * @adev: amdgpu_device pointer
  *
  * Executes the PCIE_DEVICE_READY_NOTIFICATION method
  * (all asics).
  * returns 0 on success, error on failure.
  */
 int amdgpu_acpi_pcie_notify_device_ready(struct amdgpu_device *adev)
 {
 	acpi_handle handle;
 	union acpi_object *info;
 	struct amdgpu_atcs *atcs = &adev->atcs;

 	/* Get the device handle */
 	handle = ACPI_HANDLE(&adev->pdev->dev);
 	if (!handle)
 		return -EINVAL;

 	if (!atcs->functions.pcie_dev_rdy)
 		return -EINVAL;

 	info = amdgpu_atcs_call(handle, ATCS_FUNCTION_PCIE_DEVICE_READY_NOTIFICATION, NULL);
 	if (!info)
 		return -EIO;

 	kfree(info);

 	return 0;
 }

 /**
  * amdgpu_acpi_pcie_performance_request
  *
  * @adev: amdgpu_device pointer
  * @perf_req: requested perf level (pcie gen speed)
  * @advertise: set advertise caps flag if set
  *
  * Executes the PCIE_PERFORMANCE_REQUEST method to
  * change the pcie gen speed (all asics).
  * returns 0 on success, error on failure.
  */
 int amdgpu_acpi_pcie_performance_request(struct amdgpu_device *adev,
 					 u8 perf_req, bool advertise)
 {
 	acpi_handle handle;
 	union acpi_object *info;
 	struct amdgpu_atcs *atcs = &adev->atcs;
 	struct atcs_pref_req_input atcs_input;
 	struct atcs_pref_req_output atcs_output;
 	struct acpi_buffer params;
 	size_t size;
 	u32 retry = 3;

 	/* Get the device handle */
 	handle = ACPI_HANDLE(&adev->pdev->dev);
 	if (!handle)
 		return -EINVAL;

 	if (!atcs->functions.pcie_perf_req)
 		return -EINVAL;

 	atcs_input.size = sizeof(struct atcs_pref_req_input);
 	/* client id (bit 2-0: func num, 7-3: dev num, 15-8: bus num) */
 	atcs_input.client_id = adev->pdev->devfn | (adev->pdev->bus->number << 8);
 	atcs_input.valid_flags_mask = ATCS_VALID_FLAGS_MASK;
 	atcs_input.flags = ATCS_WAIT_FOR_COMPLETION;
 	if (advertise)
 		atcs_input.flags |= ATCS_ADVERTISE_CAPS;
 	atcs_input.req_type = ATCS_PCIE_LINK_SPEED;
 	atcs_input.perf_req = perf_req;

 	params.length = sizeof(struct atcs_pref_req_input);
 	params.pointer = &atcs_input;

 	while (retry--) {
 		info = amdgpu_atcs_call(handle, ATCS_FUNCTION_PCIE_PERFORMANCE_REQUEST, &params);
 		if (!info)
 			return -EIO;

 		memset(&atcs_output, 0, sizeof(atcs_output));

 		size = *(u16 *) info->buffer.pointer;
 		if (size < 3) {
 			DRM_INFO("ATCS buffer is too small: %zu\n", size);
 			kfree(info);
 			return -EINVAL;
 		}
 		size = min(sizeof(atcs_output), size);

 		memcpy(&atcs_output, info->buffer.pointer, size);

 		kfree(info);

 		switch (atcs_output.ret_val) {
 		case ATCS_REQUEST_REFUSED:
 		default:
 			return -EINVAL;
 		case ATCS_REQUEST_COMPLETE:
 			return 0;
 		case ATCS_REQUEST_IN_PROGRESS:
 			udelay(10);
 			break;
 		}
 	}

 	return 0;
 }

 /**
  * amdgpu_acpi_event - handle notify events
  *
  * @nb: notifier block
  * @val: val
  * @data: acpi event
  *
  * Calls relevant amdgpu functions in response to various
  * acpi events.
  * Returns NOTIFY code
  */
 static int amdgpu_acpi_event(struct notifier_block *nb,
 			     unsigned long val,
 			     void *data)
 {
 	struct amdgpu_device *adev = container_of(nb, struct amdgpu_device, acpi_nb);
 	struct acpi_bus_event *entry = (struct acpi_bus_event *)data;

 	if (strcmp(entry->device_class, ACPI_AC_CLASS) == 0) {
 		if (power_supply_is_system_supplied() > 0)
 			DRM_DEBUG_DRIVER("pm: AC\n");
 		else
 			DRM_DEBUG_DRIVER("pm: DC\n");

 		amdgpu_pm_acpi_event_handler(adev);
 	}

 	/* Check for pending SBIOS requests */
 	return amdgpu_atif_handler(adev, entry);
 }

 /* Call all ACPI methods here */
 /**
  * amdgpu_acpi_init - init driver acpi support
  *
  * @adev: amdgpu_device pointer
  *
  * Verifies the AMD ACPI interfaces and registers with the acpi
  * notifier chain (all asics).
  * Returns 0 on success, error on failure.
  */
 int amdgpu_acpi_init(struct amdgpu_device *adev)
 {
 	acpi_handle handle;
 	struct amdgpu_atif *atif = &adev->atif;
 	struct amdgpu_atcs *atcs = &adev->atcs;
 	int ret;

 	/* Get the device handle */
 	handle = ACPI_HANDLE(&adev->pdev->dev);

 	if (!adev->bios || !handle)
 		return 0;

 	/* Call the ATCS method */
 	ret = amdgpu_atcs_verify_interface(handle, atcs);
 	if (ret) {
 		DRM_DEBUG_DRIVER("Call to ATCS verify_interface failed: %d\n", ret);
 	}

 	/* Call the ATIF method */
 	ret = amdgpu_atif_verify_interface(handle, atif);
 	if (ret) {
 		DRM_DEBUG_DRIVER("Call to ATIF verify_interface failed: %d\n", ret);
 		goto out;
 	}

 	if (atif->notifications.brightness_change) {
 		struct drm_encoder *tmp;

 		/* Find the encoder controlling the brightness */
 		list_for_each_entry(tmp, &adev->ddev->mode_config.encoder_list,
 				head) {
 			struct amdgpu_encoder *enc = to_amdgpu_encoder(tmp);

 			if ((enc->devices & (ATOM_DEVICE_LCD_SUPPORT)) &&
 			    enc->enc_priv) {
 				if (adev->is_atom_bios) {
 					struct amdgpu_encoder_atom_dig *dig = enc->enc_priv;
 					if (dig->bl_dev) {
 						atif->encoder_for_bl = enc;
 						break;
 					}
 				}
 			}
 		}
 	}

 	if (atif->functions.sbios_requests && !atif->functions.system_params) {
 		/* XXX check this workraround, if sbios request function is
 		 * present we have to see how it's configured in the system
 		 * params
 		 */
 		atif->functions.system_params = true;
 	}

 	if (atif->functions.system_params) {
 		ret = amdgpu_atif_get_notification_params(handle,
 				&atif->notification_cfg);
 		if (ret) {
 			DRM_DEBUG_DRIVER("Call to GET_SYSTEM_PARAMS failed: %d\n",
 					ret);
 			/* Disable notification */
 			atif->notification_cfg.enabled = false;
 		}
 	}

 out:
 	adev->acpi_nb.notifier_call = amdgpu_acpi_event;
 	register_acpi_notifier(&adev->acpi_nb);

 	return ret;
 }

 /**
  * amdgpu_acpi_fini - tear down driver acpi support
  *
  * @adev: amdgpu_device pointer
  *
  * Unregisters with the acpi notifier chain (all asics).
  */
 void amdgpu_acpi_fini(struct amdgpu_device *adev)
 {
 	unregister_acpi_notifier(&adev->acpi_nb);
 }
	/*
	* Copyright 2012 Advanced Micro Devices, Inc.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
	* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
	* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
	* OTHER DEALINGS IN THE SOFTWARE.
	*
	*/

	#include <linux/pci.h>
	#include <linux/acpi.h>
	#include <linux/slab.h>
	#include <linux/power_supply.h>
	#include <acpi/video.h>
	#include <drm/drmP.h>
	#include <drm/drm_crtc_helper.h>
	#include "amdgpu.h"
	#include "amd_acpi.h"
	#include "atom.h"

	extern void amdgpu_pm_acpi_event_handler(struct amdgpu_device *adev);
	/* Call the ATIF method
	*/
	/**
	* amdgpu_atif_call - call an ATIF method
	*
	* @handle: acpi handle
	* @function: the ATIF function to execute
	* @params: ATIF function params
	*
	* Executes the requested ATIF function (all asics).
	* Returns a pointer to the acpi output buffer.
	*/
	static union acpi_object *amdgpu_atif_call(acpi_handle handle, int function,
	struct acpi_buffer *params)
	{
	acpi_status status;
	union acpi_object atif_arg_elements[2];
	struct acpi_object_list atif_arg;
	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };

	atif_arg.count = 2;
	atif_arg.pointer = &atif_arg_elements[0];

	atif_arg_elements[0].type = ACPI_TYPE_INTEGER;
	atif_arg_elements[0].integer.value = function;

	if (params) {
	atif_arg_elements[1].type = ACPI_TYPE_BUFFER;
	atif_arg_elements[1].buffer.length = params->length;
	atif_arg_elements[1].buffer.pointer = params->pointer;
	} else {
	/* We need a second fake parameter */
	atif_arg_elements[1].type = ACPI_TYPE_INTEGER;
	atif_arg_elements[1].integer.value = 0;
	}

	status = acpi_evaluate_object(handle, "ATIF", &atif_arg, &buffer);

	/* Fail only if calling the method fails and ATIF is supported */
	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
	DRM_DEBUG_DRIVER("failed to evaluate ATIF got %s\n",
	acpi_format_exception(status));
	kfree(buffer.pointer);
	return NULL;
	}

	return buffer.pointer;
	}

	/**
	* amdgpu_atif_parse_notification - parse supported notifications
	*
	* @n: supported notifications struct
	* @mask: supported notifications mask from ATIF
	*
	* Use the supported notifications mask from ATIF function
	* ATIF_FUNCTION_VERIFY_INTERFACE to determine what notifications
	* are supported (all asics).
	*/
	static void amdgpu_atif_parse_notification(struct amdgpu_atif_notifications *n, u32 mask)
	{
	n->display_switch = mask & ATIF_DISPLAY_SWITCH_REQUEST_SUPPORTED;
	n->expansion_mode_change = mask & ATIF_EXPANSION_MODE_CHANGE_REQUEST_SUPPORTED;
	n->thermal_state = mask & ATIF_THERMAL_STATE_CHANGE_REQUEST_SUPPORTED;
	n->forced_power_state = mask & ATIF_FORCED_POWER_STATE_CHANGE_REQUEST_SUPPORTED;
	n->system_power_state = mask & ATIF_SYSTEM_POWER_SOURCE_CHANGE_REQUEST_SUPPORTED;
	n->display_conf_change = mask & ATIF_DISPLAY_CONF_CHANGE_REQUEST_SUPPORTED;
	n->px_gfx_switch = mask & ATIF_PX_GFX_SWITCH_REQUEST_SUPPORTED;
	n->brightness_change = mask & ATIF_PANEL_BRIGHTNESS_CHANGE_REQUEST_SUPPORTED;
	n->dgpu_display_event = mask & ATIF_DGPU_DISPLAY_EVENT_SUPPORTED;
	}

	/**
	* amdgpu_atif_parse_functions - parse supported functions
	*
	* @f: supported functions struct
	* @mask: supported functions mask from ATIF
	*
	* Use the supported functions mask from ATIF function
	* ATIF_FUNCTION_VERIFY_INTERFACE to determine what functions
	* are supported (all asics).
	*/
	static void amdgpu_atif_parse_functions(struct amdgpu_atif_functions *f, u32 mask)
	{
	f->system_params = mask & ATIF_GET_SYSTEM_PARAMETERS_SUPPORTED;
	f->sbios_requests = mask & ATIF_GET_SYSTEM_BIOS_REQUESTS_SUPPORTED;
	f->select_active_disp = mask & ATIF_SELECT_ACTIVE_DISPLAYS_SUPPORTED;
	f->lid_state = mask & ATIF_GET_LID_STATE_SUPPORTED;
	f->get_tv_standard = mask & ATIF_GET_TV_STANDARD_FROM_CMOS_SUPPORTED;
	f->set_tv_standard = mask & ATIF_SET_TV_STANDARD_IN_CMOS_SUPPORTED;
	f->get_panel_expansion_mode = mask & ATIF_GET_PANEL_EXPANSION_MODE_FROM_CMOS_SUPPORTED;
	f->set_panel_expansion_mode = mask & ATIF_SET_PANEL_EXPANSION_MODE_IN_CMOS_SUPPORTED;
	f->temperature_change = mask & ATIF_TEMPERATURE_CHANGE_NOTIFICATION_SUPPORTED;
	f->graphics_device_types = mask & ATIF_GET_GRAPHICS_DEVICE_TYPES_SUPPORTED;
	}

	/**
	* amdgpu_atif_verify_interface - verify ATIF
	*
	* @handle: acpi handle
	* @atif: amdgpu atif struct
	*
	* Execute the ATIF_FUNCTION_VERIFY_INTERFACE ATIF function
	* to initialize ATIF and determine what features are supported
	* (all asics).
	* returns 0 on success, error on failure.
	*/
	static int amdgpu_atif_verify_interface(acpi_handle handle,
	struct amdgpu_atif *atif)
	{
	union acpi_object *info;
	struct atif_verify_interface output;
	size_t size;
	int err = 0;

	info = amdgpu_atif_call(handle, ATIF_FUNCTION_VERIFY_INTERFACE, NULL);
	if (!info)
	return -EIO;

	memset(&output, 0, sizeof(output));

	size = (u16 ) info->buffer.pointer;
	if (size < 12) {
	DRM_INFO("ATIF buffer is too small: %zu\n", size);
	err = -EINVAL;
	goto out;
	}
	size = min(sizeof(output), size);

	memcpy(&output, info->buffer.pointer, size);

	/* TODO: check version? */
	DRM_DEBUG_DRIVER("ATIF version %u\n", output.version);

	amdgpu_atif_parse_notification(&atif->notifications, output.notification_mask);
	amdgpu_atif_parse_functions(&atif->functions, output.function_bits);

	out:
	kfree(info);
	return err;
	}

	/**
	* amdgpu_atif_get_notification_params - determine notify configuration
	*
	* @handle: acpi handle
	* @n: atif notification configuration struct
	*
	* Execute the ATIF_FUNCTION_GET_SYSTEM_PARAMETERS ATIF function
	* to determine if a notifier is used and if so which one
	* (all asics). This is either Notify(VGA, 0x81) or Notify(VGA, n)
	* where n is specified in the result if a notifier is used.
	* Returns 0 on success, error on failure.
	*/
	static int amdgpu_atif_get_notification_params(acpi_handle handle,
	struct amdgpu_atif_notification_cfg *n)
	{
	union acpi_object *info;
	struct atif_system_params params;
	size_t size;
	int err = 0;

	info = amdgpu_atif_call(handle, ATIF_FUNCTION_GET_SYSTEM_PARAMETERS, NULL);
	if (!info) {
	err = -EIO;
	goto out;
	}

	size = (u16 ) info->buffer.pointer;
	if (size < 10) {
	err = -EINVAL;
	goto out;
	}

	memset(&params, 0, sizeof(params));
	size = min(sizeof(params), size);
	memcpy(&params, info->buffer.pointer, size);

	DRM_DEBUG_DRIVER("SYSTEM_PARAMS: mask = %#x, flags = %#x\n",
	params.flags, params.valid_mask);
	params.flags = params.flags & params.valid_mask;

	if ((params.flags & ATIF_NOTIFY_MASK) == ATIF_NOTIFY_NONE) {
	n->enabled = false;
	n->command_code = 0;
	} else if ((params.flags & ATIF_NOTIFY_MASK) == ATIF_NOTIFY_81) {
	n->enabled = true;
	n->command_code = 0x81;
	} else {
	if (size < 11) {
	err = -EINVAL;
	goto out;
	}
	n->enabled = true;
	n->command_code = params.command_code;
	}

	out:
	DRM_DEBUG_DRIVER("Notification %s, command code = %#x\n",
	(n->enabled ? "enabled" : "disabled"),
	n->command_code);
	kfree(info);
	return err;
	}

	/**
	* amdgpu_atif_get_sbios_requests - get requested sbios event
	*
	* @handle: acpi handle
	* @req: atif sbios request struct
	*
	* Execute the ATIF_FUNCTION_GET_SYSTEM_BIOS_REQUESTS ATIF function
	* to determine what requests the sbios is making to the driver
	* (all asics).
	* Returns 0 on success, error on failure.
	*/
	static int amdgpu_atif_get_sbios_requests(acpi_handle handle,
	struct atif_sbios_requests *req)
	{
	union acpi_object *info;
	size_t size;
	int count = 0;

	info = amdgpu_atif_call(handle, ATIF_FUNCTION_GET_SYSTEM_BIOS_REQUESTS, NULL);
	if (!info)
	return -EIO;

	size = (u16 )info->buffer.pointer;
	if (size < 0xd) {
	count = -EINVAL;
	goto out;
	}
	memset(req, 0, sizeof(*req));

	size = min(sizeof(*req), size);
	memcpy(req, info->buffer.pointer, size);
	DRM_DEBUG_DRIVER("SBIOS pending requests: %#x\n", req->pending);

	count = hweight32(req->pending);

	out:
	kfree(info);
	return count;
	}

	/**
	* amdgpu_atif_handler - handle ATIF notify requests
	*
	* @adev: amdgpu_device pointer
	* @event: atif sbios request struct
	*
	* Checks the acpi event and if it matches an atif event,
	* handles it.
	* Returns NOTIFY code
	*/
	int amdgpu_atif_handler(struct amdgpu_device *adev,
	struct acpi_bus_event *event)
	{
	struct amdgpu_atif *atif = &adev->atif;
	struct atif_sbios_requests req;
	acpi_handle handle;
	int count;

	DRM_DEBUG_DRIVER("event, device_class = %s, type = %#x\n",
	event->device_class, event->type);

	if (strcmp(event->device_class, ACPI_VIDEO_CLASS) != 0)
	return NOTIFY_DONE;

	if (!atif->notification_cfg.enabled \|\|
	event->type != atif->notification_cfg.command_code)
	/* Not our event */
	return NOTIFY_DONE;

	/* Check pending SBIOS requests */
	handle = ACPI_HANDLE(&adev->pdev->dev);
	count = amdgpu_atif_get_sbios_requests(handle, &req);

	if (count <= 0)
	return NOTIFY_DONE;

	DRM_DEBUG_DRIVER("ATIF: %d pending SBIOS requests\n", count);

	if (req.pending & ATIF_PANEL_BRIGHTNESS_CHANGE_REQUEST) {
	struct amdgpu_encoder *enc = atif->encoder_for_bl;

	if (enc) {
	struct amdgpu_encoder_atom_dig *dig = enc->enc_priv;

	DRM_DEBUG_DRIVER("Changing brightness to %d\n",
	req.backlight_level);

	amdgpu_display_backlight_set_level(adev, enc, req.backlight_level);

	#if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) \|\| defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
	backlight_force_update(dig->bl_dev,
	BACKLIGHT_UPDATE_HOTKEY);
	#endif
	}
	}
	/* TODO: check other events */

	/* We've handled the event, stop the notifier chain. The ACPI interface
	* overloads ACPI_VIDEO_NOTIFY_PROBE, we don't want to send that to
	* userspace if the event was generated only to signal a SBIOS
	* request.
	*/
	return NOTIFY_BAD;
	}

	/* Call the ATCS method
	*/
	/**
	* amdgpu_atcs_call - call an ATCS method
	*
	* @handle: acpi handle
	* @function: the ATCS function to execute
	* @params: ATCS function params
	*
	* Executes the requested ATCS function (all asics).
	* Returns a pointer to the acpi output buffer.
	*/
	static union acpi_object *amdgpu_atcs_call(acpi_handle handle, int function,
	struct acpi_buffer *params)
	{
	acpi_status status;
	union acpi_object atcs_arg_elements[2];
	struct acpi_object_list atcs_arg;
	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };

	atcs_arg.count = 2;
	atcs_arg.pointer = &atcs_arg_elements[0];

	atcs_arg_elements[0].type = ACPI_TYPE_INTEGER;
	atcs_arg_elements[0].integer.value = function;

	if (params) {
	atcs_arg_elements[1].type = ACPI_TYPE_BUFFER;
	atcs_arg_elements[1].buffer.length = params->length;
	atcs_arg_elements[1].buffer.pointer = params->pointer;
	} else {
	/* We need a second fake parameter */
	atcs_arg_elements[1].type = ACPI_TYPE_INTEGER;
	atcs_arg_elements[1].integer.value = 0;
	}

	status = acpi_evaluate_object(handle, "ATCS", &atcs_arg, &buffer);

	/* Fail only if calling the method fails and ATIF is supported */
	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
	DRM_DEBUG_DRIVER("failed to evaluate ATCS got %s\n",
	acpi_format_exception(status));
	kfree(buffer.pointer);
	return NULL;
	}

	return buffer.pointer;
	}

	/**
	* amdgpu_atcs_parse_functions - parse supported functions
	*
	* @f: supported functions struct
	* @mask: supported functions mask from ATCS
	*
	* Use the supported functions mask from ATCS function
	* ATCS_FUNCTION_VERIFY_INTERFACE to determine what functions
	* are supported (all asics).
	*/
	static void amdgpu_atcs_parse_functions(struct amdgpu_atcs_functions *f, u32 mask)
	{
	f->get_ext_state = mask & ATCS_GET_EXTERNAL_STATE_SUPPORTED;
	f->pcie_perf_req = mask & ATCS_PCIE_PERFORMANCE_REQUEST_SUPPORTED;
	f->pcie_dev_rdy = mask & ATCS_PCIE_DEVICE_READY_NOTIFICATION_SUPPORTED;
	f->pcie_bus_width = mask & ATCS_SET_PCIE_BUS_WIDTH_SUPPORTED;
	}

	/**
	* amdgpu_atcs_verify_interface - verify ATCS
	*
	* @handle: acpi handle
	* @atcs: amdgpu atcs struct
	*
	* Execute the ATCS_FUNCTION_VERIFY_INTERFACE ATCS function
	* to initialize ATCS and determine what features are supported
	* (all asics).
	* returns 0 on success, error on failure.
	*/
	static int amdgpu_atcs_verify_interface(acpi_handle handle,
	struct amdgpu_atcs *atcs)
	{
	union acpi_object *info;
	struct atcs_verify_interface output;
	size_t size;
	int err = 0;

	info = amdgpu_atcs_call(handle, ATCS_FUNCTION_VERIFY_INTERFACE, NULL);
	if (!info)
	return -EIO;

	memset(&output, 0, sizeof(output));

	size = (u16 ) info->buffer.pointer;
	if (size < 8) {
	DRM_INFO("ATCS buffer is too small: %zu\n", size);
	err = -EINVAL;
	goto out;
	}
	size = min(sizeof(output), size);

	memcpy(&output, info->buffer.pointer, size);

	/* TODO: check version? */
	DRM_DEBUG_DRIVER("ATCS version %u\n", output.version);

	amdgpu_atcs_parse_functions(&atcs->functions, output.function_bits);

	out:
	kfree(info);
	return err;
	}

	/**
	* amdgpu_acpi_is_pcie_performance_request_supported
	*
	* @adev: amdgpu_device pointer
	*
	* Check if the ATCS pcie_perf_req and pcie_dev_rdy methods
	* are supported (all asics).
	* returns true if supported, false if not.
	*/
	bool amdgpu_acpi_is_pcie_performance_request_supported(struct amdgpu_device *adev)
	{
	struct amdgpu_atcs *atcs = &adev->atcs;

	if (atcs->functions.pcie_perf_req && atcs->functions.pcie_dev_rdy)
	return true;

	return false;
	}

	/**
	* amdgpu_acpi_pcie_notify_device_ready
	*
	* @adev: amdgpu_device pointer
	*
	* Executes the PCIE_DEVICE_READY_NOTIFICATION method
	* (all asics).
	* returns 0 on success, error on failure.
	*/
	int amdgpu_acpi_pcie_notify_device_ready(struct amdgpu_device *adev)
	{
	acpi_handle handle;
	union acpi_object *info;
	struct amdgpu_atcs *atcs = &adev->atcs;

	/* Get the device handle */
	handle = ACPI_HANDLE(&adev->pdev->dev);
	if (!handle)
	return -EINVAL;

	if (!atcs->functions.pcie_dev_rdy)
	return -EINVAL;

	info = amdgpu_atcs_call(handle, ATCS_FUNCTION_PCIE_DEVICE_READY_NOTIFICATION, NULL);
	if (!info)
	return -EIO;

	kfree(info);

	return 0;
	}

	/**
	* amdgpu_acpi_pcie_performance_request
	*
	* @adev: amdgpu_device pointer
	* @perf_req: requested perf level (pcie gen speed)
	* @advertise: set advertise caps flag if set
	*
	* Executes the PCIE_PERFORMANCE_REQUEST method to
	* change the pcie gen speed (all asics).
	* returns 0 on success, error on failure.
	*/
	int amdgpu_acpi_pcie_performance_request(struct amdgpu_device *adev,
	u8 perf_req, bool advertise)
	{
	acpi_handle handle;
	union acpi_object *info;
	struct amdgpu_atcs *atcs = &adev->atcs;
	struct atcs_pref_req_input atcs_input;
	struct atcs_pref_req_output atcs_output;
	struct acpi_buffer params;
	size_t size;
	u32 retry = 3;

	/* Get the device handle */
	handle = ACPI_HANDLE(&adev->pdev->dev);
	if (!handle)
	return -EINVAL;

	if (!atcs->functions.pcie_perf_req)
	return -EINVAL;

	atcs_input.size = sizeof(struct atcs_pref_req_input);
	/* client id (bit 2-0: func num, 7-3: dev num, 15-8: bus num) */
	atcs_input.client_id = adev->pdev->devfn \| (adev->pdev->bus->number << 8);
	atcs_input.valid_flags_mask = ATCS_VALID_FLAGS_MASK;
	atcs_input.flags = ATCS_WAIT_FOR_COMPLETION;
	if (advertise)
	atcs_input.flags \|= ATCS_ADVERTISE_CAPS;
	atcs_input.req_type = ATCS_PCIE_LINK_SPEED;
	atcs_input.perf_req = perf_req;

	params.length = sizeof(struct atcs_pref_req_input);
	params.pointer = &atcs_input;

	while (retry--) {
	info = amdgpu_atcs_call(handle, ATCS_FUNCTION_PCIE_PERFORMANCE_REQUEST, &params);
	if (!info)
	return -EIO;

	memset(&atcs_output, 0, sizeof(atcs_output));

	size = (u16 ) info->buffer.pointer;
	if (size < 3) {
	DRM_INFO("ATCS buffer is too small: %zu\n", size);
	kfree(info);
	return -EINVAL;
	}
	size = min(sizeof(atcs_output), size);

	memcpy(&atcs_output, info->buffer.pointer, size);

	kfree(info);

	switch (atcs_output.ret_val) {
	case ATCS_REQUEST_REFUSED:
	default:
	return -EINVAL;
	case ATCS_REQUEST_COMPLETE:
	return 0;
	case ATCS_REQUEST_IN_PROGRESS:
	udelay(10);
	break;
	}
	}

	return 0;
	}

	/**
	* amdgpu_acpi_event - handle notify events
	*
	* @nb: notifier block
	* @val: val
	* @data: acpi event
	*
	* Calls relevant amdgpu functions in response to various
	* acpi events.
	* Returns NOTIFY code
	*/
	static int amdgpu_acpi_event(struct notifier_block *nb,
	unsigned long val,
	void *data)
	{
	struct amdgpu_device *adev = container_of(nb, struct amdgpu_device, acpi_nb);
	struct acpi_bus_event entry = (struct acpi_bus_event )data;

	if (strcmp(entry->device_class, ACPI_AC_CLASS) == 0) {
	if (power_supply_is_system_supplied() > 0)
	DRM_DEBUG_DRIVER("pm: AC\n");
	else
	DRM_DEBUG_DRIVER("pm: DC\n");

	amdgpu_pm_acpi_event_handler(adev);
	}

	/* Check for pending SBIOS requests */
	return amdgpu_atif_handler(adev, entry);
	}

	/* Call all ACPI methods here */
	/**
	* amdgpu_acpi_init - init driver acpi support
	*
	* @adev: amdgpu_device pointer
	*
	* Verifies the AMD ACPI interfaces and registers with the acpi
	* notifier chain (all asics).
	* Returns 0 on success, error on failure.
	*/
	int amdgpu_acpi_init(struct amdgpu_device *adev)
	{
	acpi_handle handle;
	struct amdgpu_atif *atif = &adev->atif;
	struct amdgpu_atcs *atcs = &adev->atcs;
	int ret;

	/* Get the device handle */
	handle = ACPI_HANDLE(&adev->pdev->dev);

	if (!adev->bios \|\| !handle)
	return 0;

	/* Call the ATCS method */
	ret = amdgpu_atcs_verify_interface(handle, atcs);
	if (ret) {
	DRM_DEBUG_DRIVER("Call to ATCS verify_interface failed: %d\n", ret);
	}

	/* Call the ATIF method */
	ret = amdgpu_atif_verify_interface(handle, atif);
	if (ret) {
	DRM_DEBUG_DRIVER("Call to ATIF verify_interface failed: %d\n", ret);
	goto out;
	}

	if (atif->notifications.brightness_change) {
	struct drm_encoder *tmp;

	/* Find the encoder controlling the brightness */
	list_for_each_entry(tmp, &adev->ddev->mode_config.encoder_list,
	head) {
	struct amdgpu_encoder *enc = to_amdgpu_encoder(tmp);

	if ((enc->devices & (ATOM_DEVICE_LCD_SUPPORT)) &&
	enc->enc_priv) {
	if (adev->is_atom_bios) {
	struct amdgpu_encoder_atom_dig *dig = enc->enc_priv;
	if (dig->bl_dev) {
	atif->encoder_for_bl = enc;
	break;
	}
	}
	}
	}
	}

	if (atif->functions.sbios_requests && !atif->functions.system_params) {
	/* XXX check this workraround, if sbios request function is
	* present we have to see how it's configured in the system
	* params
	*/
	atif->functions.system_params = true;
	}

	if (atif->functions.system_params) {
	ret = amdgpu_atif_get_notification_params(handle,
	&atif->notification_cfg);
	if (ret) {
	DRM_DEBUG_DRIVER("Call to GET_SYSTEM_PARAMS failed: %d\n",
	ret);
	/* Disable notification */
	atif->notification_cfg.enabled = false;
	}
	}

	out:
	adev->acpi_nb.notifier_call = amdgpu_acpi_event;
	register_acpi_notifier(&adev->acpi_nb);

	return ret;
	}

	/**
	* amdgpu_acpi_fini - tear down driver acpi support
	*
	* @adev: amdgpu_device pointer
	*
	* Unregisters with the acpi notifier chain (all asics).
	*/
	void amdgpu_acpi_fini(struct amdgpu_device *adev)
	{
	unregister_acpi_notifier(&adev->acpi_nb);
	}