xref: /openbmc/linux/drivers/acpi/acpica/hwsleep.c (revision b6dcefde)
1 
2 /******************************************************************************
3  *
4  * Name: hwsleep.c - ACPI Hardware Sleep/Wake Interface
5  *
6  *****************************************************************************/
7 
8 /*
9  * Copyright (C) 2000 - 2008, Intel Corp.
10  * All rights reserved.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions, and the following disclaimer,
17  *    without modification.
18  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
19  *    substantially similar to the "NO WARRANTY" disclaimer below
20  *    ("Disclaimer") and any redistribution must be conditioned upon
21  *    including a substantially similar Disclaimer requirement for further
22  *    binary redistribution.
23  * 3. Neither the names of the above-listed copyright holders nor the names
24  *    of any contributors may be used to endorse or promote products derived
25  *    from this software without specific prior written permission.
26  *
27  * Alternatively, this software may be distributed under the terms of the
28  * GNU General Public License ("GPL") version 2 as published by the Free
29  * Software Foundation.
30  *
31  * NO WARRANTY
32  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
33  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
34  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
35  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
36  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
41  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
42  * POSSIBILITY OF SUCH DAMAGES.
43  */
44 
45 #include <acpi/acpi.h>
46 #include "accommon.h"
47 #include "actables.h"
48 #include <linux/tboot.h>
49 
50 #define _COMPONENT          ACPI_HARDWARE
51 ACPI_MODULE_NAME("hwsleep")
52 
53 /*******************************************************************************
54  *
55  * FUNCTION:    acpi_set_firmware_waking_vector
56  *
57  * PARAMETERS:  physical_address    - 32-bit physical address of ACPI real mode
58  *                                    entry point.
59  *
60  * RETURN:      Status
61  *
62  * DESCRIPTION: Sets the 32-bit firmware_waking_vector field of the FACS
63  *
64  ******************************************************************************/
65 acpi_status
66 acpi_set_firmware_waking_vector(u32 physical_address)
67 {
68 	ACPI_FUNCTION_TRACE(acpi_set_firmware_waking_vector);
69 
70 
71 	/*
72 	 * According to the ACPI specification 2.0c and later, the 64-bit
73 	 * waking vector should be cleared and the 32-bit waking vector should
74 	 * be used, unless we want the wake-up code to be called by the BIOS in
75 	 * Protected Mode.  Some systems (for example HP dv5-1004nr) are known
76 	 * to fail to resume if the 64-bit vector is used.
77 	 */
78 
79 	/* Set the 32-bit vector */
80 
81 	acpi_gbl_FACS->firmware_waking_vector = physical_address;
82 
83 	/* Clear the 64-bit vector if it exists */
84 
85 	if ((acpi_gbl_FACS->length > 32) && (acpi_gbl_FACS->version >= 1)) {
86 		acpi_gbl_FACS->xfirmware_waking_vector = 0;
87 	}
88 
89 	return_ACPI_STATUS(AE_OK);
90 }
91 
92 ACPI_EXPORT_SYMBOL(acpi_set_firmware_waking_vector)
93 
94 #if ACPI_MACHINE_WIDTH == 64
95 /*******************************************************************************
96  *
97  * FUNCTION:    acpi_set_firmware_waking_vector64
98  *
99  * PARAMETERS:  physical_address    - 64-bit physical address of ACPI protected
100  *                                    mode entry point.
101  *
102  * RETURN:      Status
103  *
104  * DESCRIPTION: Sets the 64-bit X_firmware_waking_vector field of the FACS, if
105  *              it exists in the table. This function is intended for use with
106  *              64-bit host operating systems.
107  *
108  ******************************************************************************/
109 acpi_status
110 acpi_set_firmware_waking_vector64(u64 physical_address)
111 {
112 	ACPI_FUNCTION_TRACE(acpi_set_firmware_waking_vector64);
113 
114 
115 	/* Determine if the 64-bit vector actually exists */
116 
117 	if ((acpi_gbl_FACS->length <= 32) || (acpi_gbl_FACS->version < 1)) {
118 		return_ACPI_STATUS(AE_NOT_EXIST);
119 	}
120 
121 	/* Clear 32-bit vector, set the 64-bit X_ vector */
122 
123 	acpi_gbl_FACS->firmware_waking_vector = 0;
124 	acpi_gbl_FACS->xfirmware_waking_vector = physical_address;
125 
126 	return_ACPI_STATUS(AE_OK);
127 }
128 
129 ACPI_EXPORT_SYMBOL(acpi_set_firmware_waking_vector64)
130 #endif
131 
132 /*******************************************************************************
133  *
134  * FUNCTION:    acpi_enter_sleep_state_prep
135  *
136  * PARAMETERS:  sleep_state         - Which sleep state to enter
137  *
138  * RETURN:      Status
139  *
140  * DESCRIPTION: Prepare to enter a system sleep state (see ACPI 2.0 spec p 231)
141  *              This function must execute with interrupts enabled.
142  *              We break sleeping into 2 stages so that OSPM can handle
143  *              various OS-specific tasks between the two steps.
144  *
145  ******************************************************************************/
146 acpi_status acpi_enter_sleep_state_prep(u8 sleep_state)
147 {
148 	acpi_status status;
149 	struct acpi_object_list arg_list;
150 	union acpi_object arg;
151 
152 	ACPI_FUNCTION_TRACE(acpi_enter_sleep_state_prep);
153 
154 	/* _PSW methods could be run here to enable wake-on keyboard, LAN, etc. */
155 
156 	status = acpi_get_sleep_type_data(sleep_state,
157 					  &acpi_gbl_sleep_type_a,
158 					  &acpi_gbl_sleep_type_b);
159 	if (ACPI_FAILURE(status)) {
160 		return_ACPI_STATUS(status);
161 	}
162 
163 	/* Setup parameter object */
164 
165 	arg_list.count = 1;
166 	arg_list.pointer = &arg;
167 
168 	arg.type = ACPI_TYPE_INTEGER;
169 	arg.integer.value = sleep_state;
170 
171 	/* Run the _PTS method */
172 
173 	status = acpi_evaluate_object(NULL, METHOD_NAME__PTS, &arg_list, NULL);
174 	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
175 		return_ACPI_STATUS(status);
176 	}
177 
178 	/* Setup the argument to _SST */
179 
180 	switch (sleep_state) {
181 	case ACPI_STATE_S0:
182 		arg.integer.value = ACPI_SST_WORKING;
183 		break;
184 
185 	case ACPI_STATE_S1:
186 	case ACPI_STATE_S2:
187 	case ACPI_STATE_S3:
188 		arg.integer.value = ACPI_SST_SLEEPING;
189 		break;
190 
191 	case ACPI_STATE_S4:
192 		arg.integer.value = ACPI_SST_SLEEP_CONTEXT;
193 		break;
194 
195 	default:
196 		arg.integer.value = ACPI_SST_INDICATOR_OFF;	/* Default is off */
197 		break;
198 	}
199 
200 	/*
201 	 * Set the system indicators to show the desired sleep state.
202 	 * _SST is an optional method (return no error if not found)
203 	 */
204 	status = acpi_evaluate_object(NULL, METHOD_NAME__SST, &arg_list, NULL);
205 	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
206 		ACPI_EXCEPTION((AE_INFO, status,
207 				"While executing method _SST"));
208 	}
209 
210 	return_ACPI_STATUS(AE_OK);
211 }
212 
213 ACPI_EXPORT_SYMBOL(acpi_enter_sleep_state_prep)
214 
215 static unsigned int gts, bfs;
216 module_param(gts, uint, 0644);
217 module_param(bfs, uint, 0644);
218 MODULE_PARM_DESC(gts, "Enable evaluation of _GTS on suspend.");
219 MODULE_PARM_DESC(bfs, "Enable evaluation of _BFS on resume".);
220 
221 /*******************************************************************************
222  *
223  * FUNCTION:    acpi_enter_sleep_state
224  *
225  * PARAMETERS:  sleep_state         - Which sleep state to enter
226  *
227  * RETURN:      Status
228  *
229  * DESCRIPTION: Enter a system sleep state (see ACPI 2.0 spec p 231)
230  *              THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED
231  *
232  ******************************************************************************/
233 acpi_status asmlinkage acpi_enter_sleep_state(u8 sleep_state)
234 {
235 	u32 pm1a_control;
236 	u32 pm1b_control;
237 	struct acpi_bit_register_info *sleep_type_reg_info;
238 	struct acpi_bit_register_info *sleep_enable_reg_info;
239 	u32 in_value;
240 	struct acpi_object_list arg_list;
241 	union acpi_object arg;
242 	acpi_status status;
243 
244 	ACPI_FUNCTION_TRACE(acpi_enter_sleep_state);
245 
246 	if ((acpi_gbl_sleep_type_a > ACPI_SLEEP_TYPE_MAX) ||
247 	    (acpi_gbl_sleep_type_b > ACPI_SLEEP_TYPE_MAX)) {
248 		ACPI_ERROR((AE_INFO, "Sleep values out of range: A=%X B=%X",
249 			    acpi_gbl_sleep_type_a, acpi_gbl_sleep_type_b));
250 		return_ACPI_STATUS(AE_AML_OPERAND_VALUE);
251 	}
252 
253 	sleep_type_reg_info =
254 	    acpi_hw_get_bit_register_info(ACPI_BITREG_SLEEP_TYPE);
255 	sleep_enable_reg_info =
256 	    acpi_hw_get_bit_register_info(ACPI_BITREG_SLEEP_ENABLE);
257 
258 	/* Clear wake status */
259 
260 	status =
261 	    acpi_write_bit_register(ACPI_BITREG_WAKE_STATUS, ACPI_CLEAR_STATUS);
262 	if (ACPI_FAILURE(status)) {
263 		return_ACPI_STATUS(status);
264 	}
265 
266 	/* Clear all fixed and general purpose status bits */
267 
268 	status = acpi_hw_clear_acpi_status();
269 	if (ACPI_FAILURE(status)) {
270 		return_ACPI_STATUS(status);
271 	}
272 
273 	/*
274 	 * 1) Disable/Clear all GPEs
275 	 * 2) Enable all wakeup GPEs
276 	 */
277 	status = acpi_hw_disable_all_gpes();
278 	if (ACPI_FAILURE(status)) {
279 		return_ACPI_STATUS(status);
280 	}
281 	acpi_gbl_system_awake_and_running = FALSE;
282 
283 	status = acpi_hw_enable_all_wakeup_gpes();
284 	if (ACPI_FAILURE(status)) {
285 		return_ACPI_STATUS(status);
286 	}
287 
288 	if (gts) {
289 		/* Execute the _GTS method */
290 
291 		arg_list.count = 1;
292 		arg_list.pointer = &arg;
293 		arg.type = ACPI_TYPE_INTEGER;
294 		arg.integer.value = sleep_state;
295 
296 		status = acpi_evaluate_object(NULL, METHOD_NAME__GTS, &arg_list, NULL);
297 		if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
298 			return_ACPI_STATUS(status);
299 		}
300 	}
301 
302 	/* Get current value of PM1A control */
303 
304 	status = acpi_hw_register_read(ACPI_REGISTER_PM1_CONTROL,
305 				       &pm1a_control);
306 	if (ACPI_FAILURE(status)) {
307 		return_ACPI_STATUS(status);
308 	}
309 	ACPI_DEBUG_PRINT((ACPI_DB_INIT,
310 			  "Entering sleep state [S%d]\n", sleep_state));
311 
312 	/* Clear the SLP_EN and SLP_TYP fields */
313 
314 	pm1a_control &= ~(sleep_type_reg_info->access_bit_mask |
315 			  sleep_enable_reg_info->access_bit_mask);
316 	pm1b_control = pm1a_control;
317 
318 	/* Insert the SLP_TYP bits */
319 
320 	pm1a_control |=
321 	    (acpi_gbl_sleep_type_a << sleep_type_reg_info->bit_position);
322 	pm1b_control |=
323 	    (acpi_gbl_sleep_type_b << sleep_type_reg_info->bit_position);
324 
325 	/*
326 	 * We split the writes of SLP_TYP and SLP_EN to workaround
327 	 * poorly implemented hardware.
328 	 */
329 
330 	/* Write #1: write the SLP_TYP data to the PM1 Control registers */
331 
332 	status = acpi_hw_write_pm1_control(pm1a_control, pm1b_control);
333 	if (ACPI_FAILURE(status)) {
334 		return_ACPI_STATUS(status);
335 	}
336 
337 	/* Insert the sleep enable (SLP_EN) bit */
338 
339 	pm1a_control |= sleep_enable_reg_info->access_bit_mask;
340 	pm1b_control |= sleep_enable_reg_info->access_bit_mask;
341 
342 	/* Flush caches, as per ACPI specification */
343 
344 	ACPI_FLUSH_CPU_CACHE();
345 
346 	tboot_sleep(sleep_state, pm1a_control, pm1b_control);
347 
348 	/* Write #2: Write both SLP_TYP + SLP_EN */
349 
350 	status = acpi_hw_write_pm1_control(pm1a_control, pm1b_control);
351 	if (ACPI_FAILURE(status)) {
352 		return_ACPI_STATUS(status);
353 	}
354 
355 	if (sleep_state > ACPI_STATE_S3) {
356 		/*
357 		 * We wanted to sleep > S3, but it didn't happen (by virtue of the
358 		 * fact that we are still executing!)
359 		 *
360 		 * Wait ten seconds, then try again. This is to get S4/S5 to work on
361 		 * all machines.
362 		 *
363 		 * We wait so long to allow chipsets that poll this reg very slowly
364 		 * to still read the right value. Ideally, this block would go
365 		 * away entirely.
366 		 */
367 		acpi_os_stall(10000000);
368 
369 		status = acpi_hw_register_write(ACPI_REGISTER_PM1_CONTROL,
370 						sleep_enable_reg_info->
371 						access_bit_mask);
372 		if (ACPI_FAILURE(status)) {
373 			return_ACPI_STATUS(status);
374 		}
375 	}
376 
377 	/* Wait until we enter sleep state */
378 
379 	do {
380 		status = acpi_read_bit_register(ACPI_BITREG_WAKE_STATUS,
381 						    &in_value);
382 		if (ACPI_FAILURE(status)) {
383 			return_ACPI_STATUS(status);
384 		}
385 
386 		/* Spin until we wake */
387 
388 	} while (!in_value);
389 
390 	return_ACPI_STATUS(AE_OK);
391 }
392 
393 ACPI_EXPORT_SYMBOL(acpi_enter_sleep_state)
394 
395 /*******************************************************************************
396  *
397  * FUNCTION:    acpi_enter_sleep_state_s4bios
398  *
399  * PARAMETERS:  None
400  *
401  * RETURN:      Status
402  *
403  * DESCRIPTION: Perform a S4 bios request.
404  *              THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED
405  *
406  ******************************************************************************/
407 acpi_status asmlinkage acpi_enter_sleep_state_s4bios(void)
408 {
409 	u32 in_value;
410 	acpi_status status;
411 
412 	ACPI_FUNCTION_TRACE(acpi_enter_sleep_state_s4bios);
413 
414 	/* Clear the wake status bit (PM1) */
415 
416 	status =
417 	    acpi_write_bit_register(ACPI_BITREG_WAKE_STATUS, ACPI_CLEAR_STATUS);
418 	if (ACPI_FAILURE(status)) {
419 		return_ACPI_STATUS(status);
420 	}
421 
422 	status = acpi_hw_clear_acpi_status();
423 	if (ACPI_FAILURE(status)) {
424 		return_ACPI_STATUS(status);
425 	}
426 
427 	/*
428 	 * 1) Disable/Clear all GPEs
429 	 * 2) Enable all wakeup GPEs
430 	 */
431 	status = acpi_hw_disable_all_gpes();
432 	if (ACPI_FAILURE(status)) {
433 		return_ACPI_STATUS(status);
434 	}
435 	acpi_gbl_system_awake_and_running = FALSE;
436 
437 	status = acpi_hw_enable_all_wakeup_gpes();
438 	if (ACPI_FAILURE(status)) {
439 		return_ACPI_STATUS(status);
440 	}
441 
442 	ACPI_FLUSH_CPU_CACHE();
443 
444 	status = acpi_hw_write_port(acpi_gbl_FADT.smi_command,
445 				    (u32) acpi_gbl_FADT.S4bios_request, 8);
446 
447 	do {
448 		acpi_os_stall(1000);
449 		status =
450 		    acpi_read_bit_register(ACPI_BITREG_WAKE_STATUS, &in_value);
451 		if (ACPI_FAILURE(status)) {
452 			return_ACPI_STATUS(status);
453 		}
454 	} while (!in_value);
455 
456 	return_ACPI_STATUS(AE_OK);
457 }
458 
459 ACPI_EXPORT_SYMBOL(acpi_enter_sleep_state_s4bios)
460 
461 /*******************************************************************************
462  *
463  * FUNCTION:    acpi_leave_sleep_state_prep
464  *
465  * PARAMETERS:  sleep_state         - Which sleep state we are exiting
466  *
467  * RETURN:      Status
468  *
469  * DESCRIPTION: Perform the first state of OS-independent ACPI cleanup after a
470  *              sleep.
471  *              Called with interrupts DISABLED.
472  *
473  ******************************************************************************/
474 acpi_status acpi_leave_sleep_state_prep(u8 sleep_state)
475 {
476 	struct acpi_object_list arg_list;
477 	union acpi_object arg;
478 	acpi_status status;
479 	struct acpi_bit_register_info *sleep_type_reg_info;
480 	struct acpi_bit_register_info *sleep_enable_reg_info;
481 	u32 pm1a_control;
482 	u32 pm1b_control;
483 
484 	ACPI_FUNCTION_TRACE(acpi_leave_sleep_state_prep);
485 
486 	/*
487 	 * Set SLP_TYPE and SLP_EN to state S0.
488 	 * This is unclear from the ACPI Spec, but it is required
489 	 * by some machines.
490 	 */
491 	status = acpi_get_sleep_type_data(ACPI_STATE_S0,
492 					  &acpi_gbl_sleep_type_a,
493 					  &acpi_gbl_sleep_type_b);
494 	if (ACPI_SUCCESS(status)) {
495 		sleep_type_reg_info =
496 		    acpi_hw_get_bit_register_info(ACPI_BITREG_SLEEP_TYPE);
497 		sleep_enable_reg_info =
498 		    acpi_hw_get_bit_register_info(ACPI_BITREG_SLEEP_ENABLE);
499 
500 		/* Get current value of PM1A control */
501 
502 		status = acpi_hw_register_read(ACPI_REGISTER_PM1_CONTROL,
503 					       &pm1a_control);
504 		if (ACPI_SUCCESS(status)) {
505 
506 			/* Clear the SLP_EN and SLP_TYP fields */
507 
508 			pm1a_control &= ~(sleep_type_reg_info->access_bit_mask |
509 					  sleep_enable_reg_info->
510 					  access_bit_mask);
511 			pm1b_control = pm1a_control;
512 
513 			/* Insert the SLP_TYP bits */
514 
515 			pm1a_control |= (acpi_gbl_sleep_type_a <<
516 					 sleep_type_reg_info->bit_position);
517 			pm1b_control |= (acpi_gbl_sleep_type_b <<
518 					 sleep_type_reg_info->bit_position);
519 
520 			/* Write the control registers and ignore any errors */
521 
522 			(void)acpi_hw_write_pm1_control(pm1a_control,
523 							pm1b_control);
524 		}
525 	}
526 
527 	if (bfs) {
528 		/* Execute the _BFS method */
529 
530 		arg_list.count = 1;
531 		arg_list.pointer = &arg;
532 		arg.type = ACPI_TYPE_INTEGER;
533 		arg.integer.value = sleep_state;
534 
535 		status = acpi_evaluate_object(NULL, METHOD_NAME__BFS, &arg_list, NULL);
536 		if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
537 			ACPI_EXCEPTION((AE_INFO, status, "During Method _BFS"));
538 		}
539 	}
540 	return_ACPI_STATUS(status);
541 }
542 
543 /*******************************************************************************
544  *
545  * FUNCTION:    acpi_leave_sleep_state
546  *
547  * PARAMETERS:  sleep_state         - Which sleep state we just exited
548  *
549  * RETURN:      Status
550  *
551  * DESCRIPTION: Perform OS-independent ACPI cleanup after a sleep
552  *              Called with interrupts ENABLED.
553  *
554  ******************************************************************************/
555 acpi_status acpi_leave_sleep_state(u8 sleep_state)
556 {
557 	struct acpi_object_list arg_list;
558 	union acpi_object arg;
559 	acpi_status status;
560 
561 	ACPI_FUNCTION_TRACE(acpi_leave_sleep_state);
562 
563 	/* Ensure enter_sleep_state_prep -> enter_sleep_state ordering */
564 
565 	acpi_gbl_sleep_type_a = ACPI_SLEEP_TYPE_INVALID;
566 
567 	/* Setup parameter object */
568 
569 	arg_list.count = 1;
570 	arg_list.pointer = &arg;
571 	arg.type = ACPI_TYPE_INTEGER;
572 
573 	/* Ignore any errors from these methods */
574 
575 	arg.integer.value = ACPI_SST_WAKING;
576 	status = acpi_evaluate_object(NULL, METHOD_NAME__SST, &arg_list, NULL);
577 	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
578 		ACPI_EXCEPTION((AE_INFO, status, "During Method _SST"));
579 	}
580 
581 	/*
582 	 * GPEs must be enabled before _WAK is called as GPEs
583 	 * might get fired there
584 	 *
585 	 * Restore the GPEs:
586 	 * 1) Disable/Clear all GPEs
587 	 * 2) Enable all runtime GPEs
588 	 */
589 	status = acpi_hw_disable_all_gpes();
590 	if (ACPI_FAILURE(status)) {
591 		return_ACPI_STATUS(status);
592 	}
593 	status = acpi_hw_enable_all_runtime_gpes();
594 	if (ACPI_FAILURE(status)) {
595 		return_ACPI_STATUS(status);
596 	}
597 
598 	arg.integer.value = sleep_state;
599 	status = acpi_evaluate_object(NULL, METHOD_NAME__WAK, &arg_list, NULL);
600 	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
601 		ACPI_EXCEPTION((AE_INFO, status, "During Method _WAK"));
602 	}
603 	/* TBD: _WAK "sometimes" returns stuff - do we want to look at it? */
604 
605 	/*
606 	 * Some BIOSes assume that WAK_STS will be cleared on resume and use
607 	 * it to determine whether the system is rebooting or resuming. Clear
608 	 * it for compatibility.
609 	 */
610 	acpi_write_bit_register(ACPI_BITREG_WAKE_STATUS, 1);
611 
612 	acpi_gbl_system_awake_and_running = TRUE;
613 
614 	/* Enable power button */
615 
616 	(void)
617 	    acpi_write_bit_register(acpi_gbl_fixed_event_info
618 			      [ACPI_EVENT_POWER_BUTTON].
619 			      enable_register_id, ACPI_ENABLE_EVENT);
620 
621 	(void)
622 	    acpi_write_bit_register(acpi_gbl_fixed_event_info
623 			      [ACPI_EVENT_POWER_BUTTON].
624 			      status_register_id, ACPI_CLEAR_STATUS);
625 
626 	arg.integer.value = ACPI_SST_WORKING;
627 	status = acpi_evaluate_object(NULL, METHOD_NAME__SST, &arg_list, NULL);
628 	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
629 		ACPI_EXCEPTION((AE_INFO, status, "During Method _SST"));
630 	}
631 
632 	return_ACPI_STATUS(status);
633 }
634 
635 ACPI_EXPORT_SYMBOL(acpi_leave_sleep_state)
636