xref: /linux/drivers/gpu/drm/radeon/radeon_acpi.c (revision d033a308d81ec83908760a15a841c2bd0d5e0ea3)
1 /*
2  * Copyright 2012 Advanced Micro Devices, Inc.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20  * OTHER DEALINGS IN THE SOFTWARE.
21  *
22  */
23 
24 #include <linux/pci.h>
25 #include <linux/acpi.h>
26 #include <linux/slab.h>
27 #include <linux/power_supply.h>
28 #include <acpi/acpi_drivers.h>
29 #include <acpi/acpi_bus.h>
30 #include <acpi/video.h>
31 
32 #include <drm/drmP.h>
33 #include <drm/drm_crtc_helper.h>
34 #include "radeon.h"
35 #include "radeon_acpi.h"
36 #include "atom.h"
37 
38 #include <linux/vga_switcheroo.h>
39 
40 #define ACPI_AC_CLASS           "ac_adapter"
41 
42 extern void radeon_pm_acpi_event_handler(struct radeon_device *rdev);
43 
44 struct atif_verify_interface {
45 	u16 size;		/* structure size in bytes (includes size field) */
46 	u16 version;		/* version */
47 	u32 notification_mask;	/* supported notifications mask */
48 	u32 function_bits;	/* supported functions bit vector */
49 } __packed;
50 
51 struct atif_system_params {
52 	u16 size;		/* structure size in bytes (includes size field) */
53 	u32 valid_mask;		/* valid flags mask */
54 	u32 flags;		/* flags */
55 	u8 command_code;	/* notify command code */
56 } __packed;
57 
58 struct atif_sbios_requests {
59 	u16 size;		/* structure size in bytes (includes size field) */
60 	u32 pending;		/* pending sbios requests */
61 	u8 panel_exp_mode;	/* panel expansion mode */
62 	u8 thermal_gfx;		/* thermal state: target gfx controller */
63 	u8 thermal_state;	/* thermal state: state id (0: exit state, non-0: state) */
64 	u8 forced_power_gfx;	/* forced power state: target gfx controller */
65 	u8 forced_power_state;	/* forced power state: state id */
66 	u8 system_power_src;	/* system power source */
67 	u8 backlight_level;	/* panel backlight level (0-255) */
68 } __packed;
69 
70 #define ATIF_NOTIFY_MASK	0x3
71 #define ATIF_NOTIFY_NONE	0
72 #define ATIF_NOTIFY_81		1
73 #define ATIF_NOTIFY_N		2
74 
75 struct atcs_verify_interface {
76 	u16 size;		/* structure size in bytes (includes size field) */
77 	u16 version;		/* version */
78 	u32 function_bits;	/* supported functions bit vector */
79 } __packed;
80 
81 /* Call the ATIF method
82  */
83 /**
84  * radeon_atif_call - call an ATIF method
85  *
86  * @handle: acpi handle
87  * @function: the ATIF function to execute
88  * @params: ATIF function params
89  *
90  * Executes the requested ATIF function (all asics).
91  * Returns a pointer to the acpi output buffer.
92  */
93 static union acpi_object *radeon_atif_call(acpi_handle handle, int function,
94 		struct acpi_buffer *params)
95 {
96 	acpi_status status;
97 	union acpi_object atif_arg_elements[2];
98 	struct acpi_object_list atif_arg;
99 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
100 
101 	atif_arg.count = 2;
102 	atif_arg.pointer = &atif_arg_elements[0];
103 
104 	atif_arg_elements[0].type = ACPI_TYPE_INTEGER;
105 	atif_arg_elements[0].integer.value = function;
106 
107 	if (params) {
108 		atif_arg_elements[1].type = ACPI_TYPE_BUFFER;
109 		atif_arg_elements[1].buffer.length = params->length;
110 		atif_arg_elements[1].buffer.pointer = params->pointer;
111 	} else {
112 		/* We need a second fake parameter */
113 		atif_arg_elements[1].type = ACPI_TYPE_INTEGER;
114 		atif_arg_elements[1].integer.value = 0;
115 	}
116 
117 	status = acpi_evaluate_object(handle, "ATIF", &atif_arg, &buffer);
118 
119 	/* Fail only if calling the method fails and ATIF is supported */
120 	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
121 		DRM_DEBUG_DRIVER("failed to evaluate ATIF got %s\n",
122 				 acpi_format_exception(status));
123 		kfree(buffer.pointer);
124 		return NULL;
125 	}
126 
127 	return buffer.pointer;
128 }
129 
130 /**
131  * radeon_atif_parse_notification - parse supported notifications
132  *
133  * @n: supported notifications struct
134  * @mask: supported notifications mask from ATIF
135  *
136  * Use the supported notifications mask from ATIF function
137  * ATIF_FUNCTION_VERIFY_INTERFACE to determine what notifications
138  * are supported (all asics).
139  */
140 static void radeon_atif_parse_notification(struct radeon_atif_notifications *n, u32 mask)
141 {
142 	n->display_switch = mask & ATIF_DISPLAY_SWITCH_REQUEST_SUPPORTED;
143 	n->expansion_mode_change = mask & ATIF_EXPANSION_MODE_CHANGE_REQUEST_SUPPORTED;
144 	n->thermal_state = mask & ATIF_THERMAL_STATE_CHANGE_REQUEST_SUPPORTED;
145 	n->forced_power_state = mask & ATIF_FORCED_POWER_STATE_CHANGE_REQUEST_SUPPORTED;
146 	n->system_power_state = mask & ATIF_SYSTEM_POWER_SOURCE_CHANGE_REQUEST_SUPPORTED;
147 	n->display_conf_change = mask & ATIF_DISPLAY_CONF_CHANGE_REQUEST_SUPPORTED;
148 	n->px_gfx_switch = mask & ATIF_PX_GFX_SWITCH_REQUEST_SUPPORTED;
149 	n->brightness_change = mask & ATIF_PANEL_BRIGHTNESS_CHANGE_REQUEST_SUPPORTED;
150 	n->dgpu_display_event = mask & ATIF_DGPU_DISPLAY_EVENT_SUPPORTED;
151 }
152 
153 /**
154  * radeon_atif_parse_functions - parse supported functions
155  *
156  * @f: supported functions struct
157  * @mask: supported functions mask from ATIF
158  *
159  * Use the supported functions mask from ATIF function
160  * ATIF_FUNCTION_VERIFY_INTERFACE to determine what functions
161  * are supported (all asics).
162  */
163 static void radeon_atif_parse_functions(struct radeon_atif_functions *f, u32 mask)
164 {
165 	f->system_params = mask & ATIF_GET_SYSTEM_PARAMETERS_SUPPORTED;
166 	f->sbios_requests = mask & ATIF_GET_SYSTEM_BIOS_REQUESTS_SUPPORTED;
167 	f->select_active_disp = mask & ATIF_SELECT_ACTIVE_DISPLAYS_SUPPORTED;
168 	f->lid_state = mask & ATIF_GET_LID_STATE_SUPPORTED;
169 	f->get_tv_standard = mask & ATIF_GET_TV_STANDARD_FROM_CMOS_SUPPORTED;
170 	f->set_tv_standard = mask & ATIF_SET_TV_STANDARD_IN_CMOS_SUPPORTED;
171 	f->get_panel_expansion_mode = mask & ATIF_GET_PANEL_EXPANSION_MODE_FROM_CMOS_SUPPORTED;
172 	f->set_panel_expansion_mode = mask & ATIF_SET_PANEL_EXPANSION_MODE_IN_CMOS_SUPPORTED;
173 	f->temperature_change = mask & ATIF_TEMPERATURE_CHANGE_NOTIFICATION_SUPPORTED;
174 	f->graphics_device_types = mask & ATIF_GET_GRAPHICS_DEVICE_TYPES_SUPPORTED;
175 }
176 
177 /**
178  * radeon_atif_verify_interface - verify ATIF
179  *
180  * @handle: acpi handle
181  * @atif: radeon atif struct
182  *
183  * Execute the ATIF_FUNCTION_VERIFY_INTERFACE ATIF function
184  * to initialize ATIF and determine what features are supported
185  * (all asics).
186  * returns 0 on success, error on failure.
187  */
188 static int radeon_atif_verify_interface(acpi_handle handle,
189 		struct radeon_atif *atif)
190 {
191 	union acpi_object *info;
192 	struct atif_verify_interface output;
193 	size_t size;
194 	int err = 0;
195 
196 	info = radeon_atif_call(handle, ATIF_FUNCTION_VERIFY_INTERFACE, NULL);
197 	if (!info)
198 		return -EIO;
199 
200 	memset(&output, 0, sizeof(output));
201 
202 	size = *(u16 *) info->buffer.pointer;
203 	if (size < 12) {
204 		DRM_INFO("ATIF buffer is too small: %zu\n", size);
205 		err = -EINVAL;
206 		goto out;
207 	}
208 	size = min(sizeof(output), size);
209 
210 	memcpy(&output, info->buffer.pointer, size);
211 
212 	/* TODO: check version? */
213 	DRM_DEBUG_DRIVER("ATIF version %u\n", output.version);
214 
215 	radeon_atif_parse_notification(&atif->notifications, output.notification_mask);
216 	radeon_atif_parse_functions(&atif->functions, output.function_bits);
217 
218 out:
219 	kfree(info);
220 	return err;
221 }
222 
223 /**
224  * radeon_atif_get_notification_params - determine notify configuration
225  *
226  * @handle: acpi handle
227  * @n: atif notification configuration struct
228  *
229  * Execute the ATIF_FUNCTION_GET_SYSTEM_PARAMETERS ATIF function
230  * to determine if a notifier is used and if so which one
231  * (all asics).  This is either Notify(VGA, 0x81) or Notify(VGA, n)
232  * where n is specified in the result if a notifier is used.
233  * Returns 0 on success, error on failure.
234  */
235 static int radeon_atif_get_notification_params(acpi_handle handle,
236 		struct radeon_atif_notification_cfg *n)
237 {
238 	union acpi_object *info;
239 	struct atif_system_params params;
240 	size_t size;
241 	int err = 0;
242 
243 	info = radeon_atif_call(handle, ATIF_FUNCTION_GET_SYSTEM_PARAMETERS, NULL);
244 	if (!info) {
245 		err = -EIO;
246 		goto out;
247 	}
248 
249 	size = *(u16 *) info->buffer.pointer;
250 	if (size < 10) {
251 		err = -EINVAL;
252 		goto out;
253 	}
254 
255 	memset(&params, 0, sizeof(params));
256 	size = min(sizeof(params), size);
257 	memcpy(&params, info->buffer.pointer, size);
258 
259 	DRM_DEBUG_DRIVER("SYSTEM_PARAMS: mask = %#x, flags = %#x\n",
260 			params.flags, params.valid_mask);
261 	params.flags = params.flags & params.valid_mask;
262 
263 	if ((params.flags & ATIF_NOTIFY_MASK) == ATIF_NOTIFY_NONE) {
264 		n->enabled = false;
265 		n->command_code = 0;
266 	} else if ((params.flags & ATIF_NOTIFY_MASK) == ATIF_NOTIFY_81) {
267 		n->enabled = true;
268 		n->command_code = 0x81;
269 	} else {
270 		if (size < 11) {
271 			err = -EINVAL;
272 			goto out;
273 		}
274 		n->enabled = true;
275 		n->command_code = params.command_code;
276 	}
277 
278 out:
279 	DRM_DEBUG_DRIVER("Notification %s, command code = %#x\n",
280 			(n->enabled ? "enabled" : "disabled"),
281 			n->command_code);
282 	kfree(info);
283 	return err;
284 }
285 
286 /**
287  * radeon_atif_get_sbios_requests - get requested sbios event
288  *
289  * @handle: acpi handle
290  * @req: atif sbios request struct
291  *
292  * Execute the ATIF_FUNCTION_GET_SYSTEM_BIOS_REQUESTS ATIF function
293  * to determine what requests the sbios is making to the driver
294  * (all asics).
295  * Returns 0 on success, error on failure.
296  */
297 static int radeon_atif_get_sbios_requests(acpi_handle handle,
298 		struct atif_sbios_requests *req)
299 {
300 	union acpi_object *info;
301 	size_t size;
302 	int count = 0;
303 
304 	info = radeon_atif_call(handle, ATIF_FUNCTION_GET_SYSTEM_BIOS_REQUESTS, NULL);
305 	if (!info)
306 		return -EIO;
307 
308 	size = *(u16 *)info->buffer.pointer;
309 	if (size < 0xd) {
310 		count = -EINVAL;
311 		goto out;
312 	}
313 	memset(req, 0, sizeof(*req));
314 
315 	size = min(sizeof(*req), size);
316 	memcpy(req, info->buffer.pointer, size);
317 	DRM_DEBUG_DRIVER("SBIOS pending requests: %#x\n", req->pending);
318 
319 	count = hweight32(req->pending);
320 
321 out:
322 	kfree(info);
323 	return count;
324 }
325 
326 /**
327  * radeon_atif_handler - handle ATIF notify requests
328  *
329  * @rdev: radeon_device pointer
330  * @event: atif sbios request struct
331  *
332  * Checks the acpi event and if it matches an atif event,
333  * handles it.
334  * Returns NOTIFY code
335  */
336 int radeon_atif_handler(struct radeon_device *rdev,
337 		struct acpi_bus_event *event)
338 {
339 	struct radeon_atif *atif = &rdev->atif;
340 	struct atif_sbios_requests req;
341 	acpi_handle handle;
342 	int count;
343 
344 	DRM_DEBUG_DRIVER("event, device_class = %s, type = %#x\n",
345 			event->device_class, event->type);
346 
347 	if (strcmp(event->device_class, ACPI_VIDEO_CLASS) != 0)
348 		return NOTIFY_DONE;
349 
350 	if (!atif->notification_cfg.enabled ||
351 			event->type != atif->notification_cfg.command_code)
352 		/* Not our event */
353 		return NOTIFY_DONE;
354 
355 	/* Check pending SBIOS requests */
356 	handle = DEVICE_ACPI_HANDLE(&rdev->pdev->dev);
357 	count = radeon_atif_get_sbios_requests(handle, &req);
358 
359 	if (count <= 0)
360 		return NOTIFY_DONE;
361 
362 	DRM_DEBUG_DRIVER("ATIF: %d pending SBIOS requests\n", count);
363 
364 	if (req.pending & ATIF_PANEL_BRIGHTNESS_CHANGE_REQUEST) {
365 		struct radeon_encoder *enc = atif->encoder_for_bl;
366 
367 		if (enc) {
368 			DRM_DEBUG_DRIVER("Changing brightness to %d\n",
369 					req.backlight_level);
370 
371 			radeon_set_backlight_level(rdev, enc, req.backlight_level);
372 
373 #if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) || defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
374 			if (rdev->is_atom_bios) {
375 				struct radeon_encoder_atom_dig *dig = enc->enc_priv;
376 				backlight_force_update(dig->bl_dev,
377 						       BACKLIGHT_UPDATE_HOTKEY);
378 			} else {
379 				struct radeon_encoder_lvds *dig = enc->enc_priv;
380 				backlight_force_update(dig->bl_dev,
381 						       BACKLIGHT_UPDATE_HOTKEY);
382 			}
383 #endif
384 		}
385 	}
386 	/* TODO: check other events */
387 
388 	/* We've handled the event, stop the notifier chain. The ACPI interface
389 	 * overloads ACPI_VIDEO_NOTIFY_PROBE, we don't want to send that to
390 	 * userspace if the event was generated only to signal a SBIOS
391 	 * request.
392 	 */
393 	return NOTIFY_BAD;
394 }
395 
396 /* Call the ATCS method
397  */
398 /**
399  * radeon_atcs_call - call an ATCS method
400  *
401  * @handle: acpi handle
402  * @function: the ATCS function to execute
403  * @params: ATCS function params
404  *
405  * Executes the requested ATCS function (all asics).
406  * Returns a pointer to the acpi output buffer.
407  */
408 static union acpi_object *radeon_atcs_call(acpi_handle handle, int function,
409 					   struct acpi_buffer *params)
410 {
411 	acpi_status status;
412 	union acpi_object atcs_arg_elements[2];
413 	struct acpi_object_list atcs_arg;
414 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
415 
416 	atcs_arg.count = 2;
417 	atcs_arg.pointer = &atcs_arg_elements[0];
418 
419 	atcs_arg_elements[0].type = ACPI_TYPE_INTEGER;
420 	atcs_arg_elements[0].integer.value = function;
421 
422 	if (params) {
423 		atcs_arg_elements[1].type = ACPI_TYPE_BUFFER;
424 		atcs_arg_elements[1].buffer.length = params->length;
425 		atcs_arg_elements[1].buffer.pointer = params->pointer;
426 	} else {
427 		/* We need a second fake parameter */
428 		atcs_arg_elements[1].type = ACPI_TYPE_INTEGER;
429 		atcs_arg_elements[1].integer.value = 0;
430 	}
431 
432 	status = acpi_evaluate_object(handle, "ATCS", &atcs_arg, &buffer);
433 
434 	/* Fail only if calling the method fails and ATIF is supported */
435 	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
436 		DRM_DEBUG_DRIVER("failed to evaluate ATCS got %s\n",
437 				 acpi_format_exception(status));
438 		kfree(buffer.pointer);
439 		return NULL;
440 	}
441 
442 	return buffer.pointer;
443 }
444 
445 /**
446  * radeon_atcs_parse_functions - parse supported functions
447  *
448  * @f: supported functions struct
449  * @mask: supported functions mask from ATCS
450  *
451  * Use the supported functions mask from ATCS function
452  * ATCS_FUNCTION_VERIFY_INTERFACE to determine what functions
453  * are supported (all asics).
454  */
455 static void radeon_atcs_parse_functions(struct radeon_atcs_functions *f, u32 mask)
456 {
457 	f->get_ext_state = mask & ATCS_GET_EXTERNAL_STATE_SUPPORTED;
458 	f->pcie_perf_req = mask & ATCS_PCIE_PERFORMANCE_REQUEST_SUPPORTED;
459 	f->pcie_dev_rdy = mask & ATCS_PCIE_DEVICE_READY_NOTIFICATION_SUPPORTED;
460 	f->pcie_bus_width = mask & ATCS_SET_PCIE_BUS_WIDTH_SUPPORTED;
461 }
462 
463 /**
464  * radeon_atcs_verify_interface - verify ATCS
465  *
466  * @handle: acpi handle
467  * @atcs: radeon atcs struct
468  *
469  * Execute the ATCS_FUNCTION_VERIFY_INTERFACE ATCS function
470  * to initialize ATCS and determine what features are supported
471  * (all asics).
472  * returns 0 on success, error on failure.
473  */
474 static int radeon_atcs_verify_interface(acpi_handle handle,
475 					struct radeon_atcs *atcs)
476 {
477 	union acpi_object *info;
478 	struct atcs_verify_interface output;
479 	size_t size;
480 	int err = 0;
481 
482 	info = radeon_atcs_call(handle, ATCS_FUNCTION_VERIFY_INTERFACE, NULL);
483 	if (!info)
484 		return -EIO;
485 
486 	memset(&output, 0, sizeof(output));
487 
488 	size = *(u16 *) info->buffer.pointer;
489 	if (size < 8) {
490 		DRM_INFO("ATCS buffer is too small: %zu\n", size);
491 		err = -EINVAL;
492 		goto out;
493 	}
494 	size = min(sizeof(output), size);
495 
496 	memcpy(&output, info->buffer.pointer, size);
497 
498 	/* TODO: check version? */
499 	DRM_DEBUG_DRIVER("ATCS version %u\n", output.version);
500 
501 	radeon_atcs_parse_functions(&atcs->functions, output.function_bits);
502 
503 out:
504 	kfree(info);
505 	return err;
506 }
507 
508 /**
509  * radeon_acpi_event - handle notify events
510  *
511  * @nb: notifier block
512  * @val: val
513  * @data: acpi event
514  *
515  * Calls relevant radeon functions in response to various
516  * acpi events.
517  * Returns NOTIFY code
518  */
519 static int radeon_acpi_event(struct notifier_block *nb,
520 			     unsigned long val,
521 			     void *data)
522 {
523 	struct radeon_device *rdev = container_of(nb, struct radeon_device, acpi_nb);
524 	struct acpi_bus_event *entry = (struct acpi_bus_event *)data;
525 
526 	if (strcmp(entry->device_class, ACPI_AC_CLASS) == 0) {
527 		if (power_supply_is_system_supplied() > 0)
528 			DRM_DEBUG_DRIVER("pm: AC\n");
529 		else
530 			DRM_DEBUG_DRIVER("pm: DC\n");
531 
532 		radeon_pm_acpi_event_handler(rdev);
533 	}
534 
535 	/* Check for pending SBIOS requests */
536 	return radeon_atif_handler(rdev, entry);
537 }
538 
539 /* Call all ACPI methods here */
540 /**
541  * radeon_acpi_init - init driver acpi support
542  *
543  * @rdev: radeon_device pointer
544  *
545  * Verifies the AMD ACPI interfaces and registers with the acpi
546  * notifier chain (all asics).
547  * Returns 0 on success, error on failure.
548  */
549 int radeon_acpi_init(struct radeon_device *rdev)
550 {
551 	acpi_handle handle;
552 	struct radeon_atif *atif = &rdev->atif;
553 	struct radeon_atcs *atcs = &rdev->atcs;
554 	int ret;
555 
556 	/* Get the device handle */
557 	handle = DEVICE_ACPI_HANDLE(&rdev->pdev->dev);
558 
559 	/* No need to proceed if we're sure that ATIF is not supported */
560 	if (!ASIC_IS_AVIVO(rdev) || !rdev->bios || !handle)
561 		return 0;
562 
563 	/* Call the ATCS method */
564 	ret = radeon_atcs_verify_interface(handle, atcs);
565 	if (ret) {
566 		DRM_DEBUG_DRIVER("Call to ATCS verify_interface failed: %d\n", ret);
567 	}
568 
569 	/* Call the ATIF method */
570 	ret = radeon_atif_verify_interface(handle, atif);
571 	if (ret) {
572 		DRM_DEBUG_DRIVER("Call to ATIF verify_interface failed: %d\n", ret);
573 		goto out;
574 	}
575 
576 	if (atif->notifications.brightness_change) {
577 		struct drm_encoder *tmp;
578 		struct radeon_encoder *target = NULL;
579 
580 		/* Find the encoder controlling the brightness */
581 		list_for_each_entry(tmp, &rdev->ddev->mode_config.encoder_list,
582 				head) {
583 			struct radeon_encoder *enc = to_radeon_encoder(tmp);
584 
585 			if ((enc->devices & (ATOM_DEVICE_LCD_SUPPORT)) &&
586 			    enc->enc_priv) {
587 				if (rdev->is_atom_bios) {
588 					struct radeon_encoder_atom_dig *dig = enc->enc_priv;
589 					if (dig->bl_dev) {
590 						target = enc;
591 						break;
592 					}
593 				} else {
594 					struct radeon_encoder_lvds *dig = enc->enc_priv;
595 					if (dig->bl_dev) {
596 						target = enc;
597 						break;
598 					}
599 				}
600 			}
601 		}
602 
603 		atif->encoder_for_bl = target;
604 		if (!target) {
605 			/* Brightness change notification is enabled, but we
606 			 * didn't find a backlight controller, this should
607 			 * never happen.
608 			 */
609 			DRM_ERROR("Cannot find a backlight controller\n");
610 		}
611 	}
612 
613 	if (atif->functions.sbios_requests && !atif->functions.system_params) {
614 		/* XXX check this workraround, if sbios request function is
615 		 * present we have to see how it's configured in the system
616 		 * params
617 		 */
618 		atif->functions.system_params = true;
619 	}
620 
621 	if (atif->functions.system_params) {
622 		ret = radeon_atif_get_notification_params(handle,
623 				&atif->notification_cfg);
624 		if (ret) {
625 			DRM_DEBUG_DRIVER("Call to GET_SYSTEM_PARAMS failed: %d\n",
626 					ret);
627 			/* Disable notification */
628 			atif->notification_cfg.enabled = false;
629 		}
630 	}
631 
632 out:
633 	rdev->acpi_nb.notifier_call = radeon_acpi_event;
634 	register_acpi_notifier(&rdev->acpi_nb);
635 
636 	return ret;
637 }
638 
639 /**
640  * radeon_acpi_fini - tear down driver acpi support
641  *
642  * @rdev: radeon_device pointer
643  *
644  * Unregisters with the acpi notifier chain (all asics).
645  */
646 void radeon_acpi_fini(struct radeon_device *rdev)
647 {
648 	unregister_acpi_notifier(&rdev->acpi_nb);
649 }
650