1 /******************************************************************************
2  *
3  * Module Name: nsinit - namespace initialization
4  *
5  *****************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2019, Intel Corp.
9  * All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions, and the following disclaimer,
16  *    without modification.
17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
18  *    substantially similar to the "NO WARRANTY" disclaimer below
19  *    ("Disclaimer") and any redistribution must be conditioned upon
20  *    including a substantially similar Disclaimer requirement for further
21  *    binary redistribution.
22  * 3. Neither the names of the above-listed copyright holders nor the names
23  *    of any contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * Alternatively, this software may be distributed under the terms of the
27  * GNU General Public License ("GPL") version 2 as published by the Free
28  * Software Foundation.
29  *
30  * NO WARRANTY
31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
41  * POSSIBILITY OF SUCH DAMAGES.
42  */
43 
44 #include "acpi.h"
45 #include "accommon.h"
46 #include "acnamesp.h"
47 #include "acdispat.h"
48 #include "acinterp.h"
49 #include "acevents.h"
50 
51 #define _COMPONENT          ACPI_NAMESPACE
52         ACPI_MODULE_NAME    ("nsinit")
53 
54 /* Local prototypes */
55 
56 static ACPI_STATUS
57 AcpiNsInitOneObject (
58     ACPI_HANDLE             ObjHandle,
59     UINT32                  Level,
60     void                    *Context,
61     void                    **ReturnValue);
62 
63 static ACPI_STATUS
64 AcpiNsInitOneDevice (
65     ACPI_HANDLE             ObjHandle,
66     UINT32                  NestingLevel,
67     void                    *Context,
68     void                    **ReturnValue);
69 
70 static ACPI_STATUS
71 AcpiNsFindIniMethods (
72     ACPI_HANDLE             ObjHandle,
73     UINT32                  NestingLevel,
74     void                    *Context,
75     void                    **ReturnValue);
76 
77 
78 /*******************************************************************************
79  *
80  * FUNCTION:    AcpiNsInitializeObjects
81  *
82  * PARAMETERS:  None
83  *
84  * RETURN:      Status
85  *
86  * DESCRIPTION: Walk the entire namespace and perform any necessary
87  *              initialization on the objects found therein
88  *
89  ******************************************************************************/
90 
91 ACPI_STATUS
92 AcpiNsInitializeObjects (
93     void)
94 {
95     ACPI_STATUS             Status;
96     ACPI_INIT_WALK_INFO     Info;
97 
98 
99     ACPI_FUNCTION_TRACE (NsInitializeObjects);
100 
101 
102     ACPI_DEBUG_PRINT ((ACPI_DB_EXEC,
103         "[Init] Completing Initialization of ACPI Objects\n"));
104     ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
105         "**** Starting initialization of namespace objects ****\n"));
106     ACPI_DEBUG_PRINT_RAW ((ACPI_DB_INIT,
107         "Completing Region/Field/Buffer/Package initialization:\n"));
108 
109     /* Set all init info to zero */
110 
111     memset (&Info, 0, sizeof (ACPI_INIT_WALK_INFO));
112 
113     /* Walk entire namespace from the supplied root */
114 
115     Status = AcpiWalkNamespace (ACPI_TYPE_ANY, ACPI_ROOT_OBJECT,
116         ACPI_UINT32_MAX, AcpiNsInitOneObject, NULL,
117         &Info, NULL);
118     if (ACPI_FAILURE (Status))
119     {
120         ACPI_EXCEPTION ((AE_INFO, Status, "During WalkNamespace"));
121     }
122 
123     ACPI_DEBUG_PRINT_RAW ((ACPI_DB_INIT,
124         "    Initialized %u/%u Regions %u/%u Fields %u/%u "
125         "Buffers %u/%u Packages (%u nodes)\n",
126         Info.OpRegionInit,  Info.OpRegionCount,
127         Info.FieldInit,     Info.FieldCount,
128         Info.BufferInit,    Info.BufferCount,
129         Info.PackageInit,   Info.PackageCount, Info.ObjectCount));
130 
131     ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
132         "%u Control Methods found\n%u Op Regions found\n",
133         Info.MethodCount, Info.OpRegionCount));
134 
135     return_ACPI_STATUS (AE_OK);
136 }
137 
138 
139 /*******************************************************************************
140  *
141  * FUNCTION:    AcpiNsInitializeDevices
142  *
143  * PARAMETERS:  None
144  *
145  * RETURN:      ACPI_STATUS
146  *
147  * DESCRIPTION: Walk the entire namespace and initialize all ACPI devices.
148  *              This means running _INI on all present devices.
149  *
150  *              Note: We install PCI config space handler on region access,
151  *              not here.
152  *
153  ******************************************************************************/
154 
155 ACPI_STATUS
156 AcpiNsInitializeDevices (
157     UINT32                  Flags)
158 {
159     ACPI_STATUS             Status = AE_OK;
160     ACPI_DEVICE_WALK_INFO   Info;
161     ACPI_HANDLE             Handle;
162 
163 
164     ACPI_FUNCTION_TRACE (NsInitializeDevices);
165 
166 
167     if (!(Flags & ACPI_NO_DEVICE_INIT))
168     {
169         ACPI_DEBUG_PRINT ((ACPI_DB_EXEC,
170             "[Init] Initializing ACPI Devices\n"));
171 
172         /* Init counters */
173 
174         Info.DeviceCount = 0;
175         Info.Num_STA = 0;
176         Info.Num_INI = 0;
177 
178         ACPI_DEBUG_PRINT_RAW ((ACPI_DB_INIT,
179             "Initializing Device/Processor/Thermal objects "
180             "and executing _INI/_STA methods:\n"));
181 
182         /* Tree analysis: find all subtrees that contain _INI methods */
183 
184         Status = AcpiNsWalkNamespace (ACPI_TYPE_ANY, ACPI_ROOT_OBJECT,
185             ACPI_UINT32_MAX, FALSE, AcpiNsFindIniMethods, NULL, &Info, NULL);
186         if (ACPI_FAILURE (Status))
187         {
188             goto ErrorExit;
189         }
190 
191         /* Allocate the evaluation information block */
192 
193         Info.EvaluateInfo = ACPI_ALLOCATE_ZEROED (sizeof (ACPI_EVALUATE_INFO));
194         if (!Info.EvaluateInfo)
195         {
196             Status = AE_NO_MEMORY;
197             goto ErrorExit;
198         }
199 
200         /*
201          * Execute the "global" _INI method that may appear at the root.
202          * This support is provided for Windows compatibility (Vista+) and
203          * is not part of the ACPI specification.
204          */
205         Info.EvaluateInfo->PrefixNode = AcpiGbl_RootNode;
206         Info.EvaluateInfo->RelativePathname = METHOD_NAME__INI;
207         Info.EvaluateInfo->Parameters = NULL;
208         Info.EvaluateInfo->Flags = ACPI_IGNORE_RETURN_VALUE;
209 
210         Status = AcpiNsEvaluate (Info.EvaluateInfo);
211         if (ACPI_SUCCESS (Status))
212         {
213             Info.Num_INI++;
214         }
215 
216         /*
217          * Execute \_SB._INI.
218          * There appears to be a strict order requirement for \_SB._INI,
219          * which should be evaluated before any _REG evaluations.
220          */
221         Status = AcpiGetHandle (NULL, "\\_SB", &Handle);
222         if (ACPI_SUCCESS (Status))
223         {
224             memset (Info.EvaluateInfo, 0, sizeof (ACPI_EVALUATE_INFO));
225             Info.EvaluateInfo->PrefixNode = Handle;
226             Info.EvaluateInfo->RelativePathname = METHOD_NAME__INI;
227             Info.EvaluateInfo->Parameters = NULL;
228             Info.EvaluateInfo->Flags = ACPI_IGNORE_RETURN_VALUE;
229 
230             Status = AcpiNsEvaluate (Info.EvaluateInfo);
231             if (ACPI_SUCCESS (Status))
232             {
233                 Info.Num_INI++;
234             }
235         }
236     }
237 
238     /*
239      * Run all _REG methods
240      *
241      * Note: Any objects accessed by the _REG methods will be automatically
242      * initialized, even if they contain executable AML (see the call to
243      * AcpiNsInitializeObjects below).
244      *
245      * Note: According to the ACPI specification, we actually needn't execute
246      * _REG for SystemMemory/SystemIo operation regions, but for PCI_Config
247      * operation regions, it is required to evaluate _REG for those on a PCI
248      * root bus that doesn't contain _BBN object. So this code is kept here
249      * in order not to break things.
250      */
251     if (!(Flags & ACPI_NO_ADDRESS_SPACE_INIT))
252     {
253         ACPI_DEBUG_PRINT ((ACPI_DB_EXEC,
254             "[Init] Executing _REG OpRegion methods\n"));
255 
256         Status = AcpiEvInitializeOpRegions ();
257         if (ACPI_FAILURE (Status))
258         {
259             goto ErrorExit;
260         }
261     }
262 
263     if (!(Flags & ACPI_NO_DEVICE_INIT))
264     {
265         /* Walk namespace to execute all _INIs on present devices */
266 
267         Status = AcpiNsWalkNamespace (ACPI_TYPE_ANY, ACPI_ROOT_OBJECT,
268             ACPI_UINT32_MAX, FALSE, AcpiNsInitOneDevice, NULL, &Info, NULL);
269 
270         /*
271          * Any _OSI requests should be completed by now. If the BIOS has
272          * requested any Windows OSI strings, we will always truncate
273          * I/O addresses to 16 bits -- for Windows compatibility.
274          */
275         if (AcpiGbl_OsiData >= ACPI_OSI_WIN_2000)
276         {
277             AcpiGbl_TruncateIoAddresses = TRUE;
278         }
279 
280         ACPI_FREE (Info.EvaluateInfo);
281         if (ACPI_FAILURE (Status))
282         {
283             goto ErrorExit;
284         }
285 
286         ACPI_DEBUG_PRINT_RAW ((ACPI_DB_INIT,
287             "    Executed %u _INI methods requiring %u _STA executions "
288             "(examined %u objects)\n",
289             Info.Num_INI, Info.Num_STA, Info.DeviceCount));
290     }
291 
292     return_ACPI_STATUS (Status);
293 
294 
295 ErrorExit:
296     ACPI_EXCEPTION ((AE_INFO, Status, "During device initialization"));
297     return_ACPI_STATUS (Status);
298 }
299 
300 
301 /*******************************************************************************
302  *
303  * FUNCTION:    AcpiNsInitOnePackage
304  *
305  * PARAMETERS:  ObjHandle       - Node
306  *              Level           - Current nesting level
307  *              Context         - Not used
308  *              ReturnValue     - Not used
309  *
310  * RETURN:      Status
311  *
312  * DESCRIPTION: Callback from AcpiWalkNamespace. Invoked for every package
313  *              within the namespace. Used during dynamic load of an SSDT.
314  *
315  ******************************************************************************/
316 
317 ACPI_STATUS
318 AcpiNsInitOnePackage (
319     ACPI_HANDLE             ObjHandle,
320     UINT32                  Level,
321     void                    *Context,
322     void                    **ReturnValue)
323 {
324     ACPI_STATUS             Status;
325     ACPI_OPERAND_OBJECT     *ObjDesc;
326     ACPI_NAMESPACE_NODE     *Node = (ACPI_NAMESPACE_NODE *) ObjHandle;
327 
328 
329     ObjDesc = AcpiNsGetAttachedObject (Node);
330     if (!ObjDesc)
331     {
332         return (AE_OK);
333     }
334 
335     /* Exit if package is already initialized */
336 
337     if (ObjDesc->Package.Flags & AOPOBJ_DATA_VALID)
338     {
339         return (AE_OK);
340     }
341 
342     Status = AcpiDsGetPackageArguments (ObjDesc);
343     if (ACPI_FAILURE (Status))
344     {
345         return (AE_OK);
346     }
347 
348     Status = AcpiUtWalkPackageTree (ObjDesc, NULL, AcpiDsInitPackageElement,
349         NULL);
350     if (ACPI_FAILURE (Status))
351     {
352         return (AE_OK);
353     }
354 
355     ObjDesc->Package.Flags |= AOPOBJ_DATA_VALID;
356     return (AE_OK);
357 }
358 
359 
360 /*******************************************************************************
361  *
362  * FUNCTION:    AcpiNsInitOneObject
363  *
364  * PARAMETERS:  ObjHandle       - Node
365  *              Level           - Current nesting level
366  *              Context         - Points to a init info struct
367  *              ReturnValue     - Not used
368  *
369  * RETURN:      Status
370  *
371  * DESCRIPTION: Callback from AcpiWalkNamespace. Invoked for every object
372  *              within the namespace.
373  *
374  *              Currently, the only objects that require initialization are:
375  *              1) Methods
376  *              2) Op Regions
377  *
378  ******************************************************************************/
379 
380 static ACPI_STATUS
381 AcpiNsInitOneObject (
382     ACPI_HANDLE             ObjHandle,
383     UINT32                  Level,
384     void                    *Context,
385     void                    **ReturnValue)
386 {
387     ACPI_OBJECT_TYPE        Type;
388     ACPI_STATUS             Status = AE_OK;
389     ACPI_INIT_WALK_INFO     *Info = (ACPI_INIT_WALK_INFO *) Context;
390     ACPI_NAMESPACE_NODE     *Node = (ACPI_NAMESPACE_NODE *) ObjHandle;
391     ACPI_OPERAND_OBJECT     *ObjDesc;
392 
393 
394     ACPI_FUNCTION_NAME (NsInitOneObject);
395 
396 
397     Info->ObjectCount++;
398 
399     /* And even then, we are only interested in a few object types */
400 
401     Type = AcpiNsGetType (ObjHandle);
402     ObjDesc = AcpiNsGetAttachedObject (Node);
403     if (!ObjDesc)
404     {
405         return (AE_OK);
406     }
407 
408     /* Increment counters for object types we are looking for */
409 
410     switch (Type)
411     {
412     case ACPI_TYPE_REGION:
413 
414         Info->OpRegionCount++;
415         break;
416 
417     case ACPI_TYPE_BUFFER_FIELD:
418 
419         Info->FieldCount++;
420         break;
421 
422     case ACPI_TYPE_LOCAL_BANK_FIELD:
423 
424         Info->FieldCount++;
425         break;
426 
427     case ACPI_TYPE_BUFFER:
428 
429         Info->BufferCount++;
430         break;
431 
432     case ACPI_TYPE_PACKAGE:
433 
434         Info->PackageCount++;
435         break;
436 
437     default:
438 
439         /* No init required, just exit now */
440 
441         return (AE_OK);
442     }
443 
444     /* If the object is already initialized, nothing else to do */
445 
446     if (ObjDesc->Common.Flags & AOPOBJ_DATA_VALID)
447     {
448         return (AE_OK);
449     }
450 
451     /* Must lock the interpreter before executing AML code */
452 
453     AcpiExEnterInterpreter ();
454 
455     /*
456      * Each of these types can contain executable AML code within the
457      * declaration.
458      */
459     switch (Type)
460     {
461     case ACPI_TYPE_REGION:
462 
463         Info->OpRegionInit++;
464         Status = AcpiDsGetRegionArguments (ObjDesc);
465         break;
466 
467     case ACPI_TYPE_BUFFER_FIELD:
468 
469         Info->FieldInit++;
470         Status = AcpiDsGetBufferFieldArguments (ObjDesc);
471         break;
472 
473     case ACPI_TYPE_LOCAL_BANK_FIELD:
474 
475         Info->FieldInit++;
476         Status = AcpiDsGetBankFieldArguments (ObjDesc);
477         break;
478 
479     case ACPI_TYPE_BUFFER:
480 
481         Info->BufferInit++;
482         Status = AcpiDsGetBufferArguments (ObjDesc);
483         break;
484 
485     case ACPI_TYPE_PACKAGE:
486 
487         /* Complete the initialization/resolution of the package object */
488 
489         Info->PackageInit++;
490         Status = AcpiNsInitOnePackage (ObjHandle, Level, NULL, NULL);
491         break;
492 
493     default:
494 
495         /* No other types can get here */
496 
497         break;
498     }
499 
500     if (ACPI_FAILURE (Status))
501     {
502         ACPI_EXCEPTION ((AE_INFO, Status,
503             "Could not execute arguments for [%4.4s] (%s)",
504             AcpiUtGetNodeName (Node), AcpiUtGetTypeName (Type)));
505     }
506 
507     /*
508      * We ignore errors from above, and always return OK, since we don't want
509      * to abort the walk on any single error.
510      */
511     AcpiExExitInterpreter ();
512     return (AE_OK);
513 }
514 
515 
516 /*******************************************************************************
517  *
518  * FUNCTION:    AcpiNsFindIniMethods
519  *
520  * PARAMETERS:  ACPI_WALK_CALLBACK
521  *
522  * RETURN:      ACPI_STATUS
523  *
524  * DESCRIPTION: Called during namespace walk. Finds objects named _INI under
525  *              device/processor/thermal objects, and marks the entire subtree
526  *              with a SUBTREE_HAS_INI flag. This flag is used during the
527  *              subsequent device initialization walk to avoid entire subtrees
528  *              that do not contain an _INI.
529  *
530  ******************************************************************************/
531 
532 static ACPI_STATUS
533 AcpiNsFindIniMethods (
534     ACPI_HANDLE             ObjHandle,
535     UINT32                  NestingLevel,
536     void                    *Context,
537     void                    **ReturnValue)
538 {
539     ACPI_DEVICE_WALK_INFO   *Info = ACPI_CAST_PTR (ACPI_DEVICE_WALK_INFO, Context);
540     ACPI_NAMESPACE_NODE     *Node;
541     ACPI_NAMESPACE_NODE     *ParentNode;
542 
543 
544     /* Keep count of device/processor/thermal objects */
545 
546     Node = ACPI_CAST_PTR (ACPI_NAMESPACE_NODE, ObjHandle);
547     if ((Node->Type == ACPI_TYPE_DEVICE)    ||
548         (Node->Type == ACPI_TYPE_PROCESSOR) ||
549         (Node->Type == ACPI_TYPE_THERMAL))
550     {
551         Info->DeviceCount++;
552         return (AE_OK);
553     }
554 
555     /* We are only looking for methods named _INI */
556 
557     if (!ACPI_COMPARE_NAME (Node->Name.Ascii, METHOD_NAME__INI))
558     {
559         return (AE_OK);
560     }
561 
562     /*
563      * The only _INI methods that we care about are those that are
564      * present under Device, Processor, and Thermal objects.
565      */
566     ParentNode = Node->Parent;
567     switch (ParentNode->Type)
568     {
569     case ACPI_TYPE_DEVICE:
570     case ACPI_TYPE_PROCESSOR:
571     case ACPI_TYPE_THERMAL:
572 
573         /* Mark parent and bubble up the INI present flag to the root */
574 
575         while (ParentNode)
576         {
577             ParentNode->Flags |= ANOBJ_SUBTREE_HAS_INI;
578             ParentNode = ParentNode->Parent;
579         }
580         break;
581 
582     default:
583 
584         break;
585     }
586 
587     return (AE_OK);
588 }
589 
590 
591 /*******************************************************************************
592  *
593  * FUNCTION:    AcpiNsInitOneDevice
594  *
595  * PARAMETERS:  ACPI_WALK_CALLBACK
596  *
597  * RETURN:      ACPI_STATUS
598  *
599  * DESCRIPTION: This is called once per device soon after ACPI is enabled
600  *              to initialize each device. It determines if the device is
601  *              present, and if so, calls _INI.
602  *
603  ******************************************************************************/
604 
605 static ACPI_STATUS
606 AcpiNsInitOneDevice (
607     ACPI_HANDLE             ObjHandle,
608     UINT32                  NestingLevel,
609     void                    *Context,
610     void                    **ReturnValue)
611 {
612     ACPI_DEVICE_WALK_INFO   *WalkInfo = ACPI_CAST_PTR (ACPI_DEVICE_WALK_INFO, Context);
613     ACPI_EVALUATE_INFO      *Info = WalkInfo->EvaluateInfo;
614     UINT32                  Flags;
615     ACPI_STATUS             Status;
616     ACPI_NAMESPACE_NODE     *DeviceNode;
617 
618 
619     ACPI_FUNCTION_TRACE (NsInitOneDevice);
620 
621 
622     /* We are interested in Devices, Processors and ThermalZones only */
623 
624     DeviceNode = ACPI_CAST_PTR (ACPI_NAMESPACE_NODE, ObjHandle);
625     if ((DeviceNode->Type != ACPI_TYPE_DEVICE)    &&
626         (DeviceNode->Type != ACPI_TYPE_PROCESSOR) &&
627         (DeviceNode->Type != ACPI_TYPE_THERMAL))
628     {
629         return_ACPI_STATUS (AE_OK);
630     }
631 
632     /*
633      * Because of an earlier namespace analysis, all subtrees that contain an
634      * _INI method are tagged.
635      *
636      * If this device subtree does not contain any _INI methods, we
637      * can exit now and stop traversing this entire subtree.
638      */
639     if (!(DeviceNode->Flags & ANOBJ_SUBTREE_HAS_INI))
640     {
641         return_ACPI_STATUS (AE_CTRL_DEPTH);
642     }
643 
644     /*
645      * Run _STA to determine if this device is present and functioning. We
646      * must know this information for two important reasons (from ACPI spec):
647      *
648      * 1) We can only run _INI if the device is present.
649      * 2) We must abort the device tree walk on this subtree if the device is
650      *    not present and is not functional (we will not examine the children)
651      *
652      * The _STA method is not required to be present under the device, we
653      * assume the device is present if _STA does not exist.
654      */
655     ACPI_DEBUG_EXEC (AcpiUtDisplayInitPathname (
656         ACPI_TYPE_METHOD, DeviceNode, METHOD_NAME__STA));
657 
658     Status = AcpiUtExecute_STA (DeviceNode, &Flags);
659     if (ACPI_FAILURE (Status))
660     {
661         /* Ignore error and move on to next device */
662 
663         return_ACPI_STATUS (AE_OK);
664     }
665 
666     /*
667      * Flags == -1 means that _STA was not found. In this case, we assume that
668      * the device is both present and functional.
669      *
670      * From the ACPI spec, description of _STA:
671      *
672      * "If a device object (including the processor object) does not have an
673      * _STA object, then OSPM assumes that all of the above bits are set (in
674      * other words, the device is present, ..., and functioning)"
675      */
676     if (Flags != ACPI_UINT32_MAX)
677     {
678         WalkInfo->Num_STA++;
679     }
680 
681     /*
682      * Examine the PRESENT and FUNCTIONING status bits
683      *
684      * Note: ACPI spec does not seem to specify behavior for the present but
685      * not functioning case, so we assume functioning if present.
686      */
687     if (!(Flags & ACPI_STA_DEVICE_PRESENT))
688     {
689         /* Device is not present, we must examine the Functioning bit */
690 
691         if (Flags & ACPI_STA_DEVICE_FUNCTIONING)
692         {
693             /*
694              * Device is not present but is "functioning". In this case,
695              * we will not run _INI, but we continue to examine the children
696              * of this device.
697              *
698              * From the ACPI spec, description of _STA: (Note - no mention
699              * of whether to run _INI or not on the device in question)
700              *
701              * "_STA may return bit 0 clear (not present) with bit 3 set
702              * (device is functional). This case is used to indicate a valid
703              * device for which no device driver should be loaded (for example,
704              * a bridge device.) Children of this device may be present and
705              * valid. OSPM should continue enumeration below a device whose
706              * _STA returns this bit combination"
707              */
708             return_ACPI_STATUS (AE_OK);
709         }
710         else
711         {
712             /*
713              * Device is not present and is not functioning. We must abort the
714              * walk of this subtree immediately -- don't look at the children
715              * of such a device.
716              *
717              * From the ACPI spec, description of _INI:
718              *
719              * "If the _STA method indicates that the device is not present,
720              * OSPM will not run the _INI and will not examine the children
721              * of the device for _INI methods"
722              */
723             return_ACPI_STATUS (AE_CTRL_DEPTH);
724         }
725     }
726 
727     /*
728      * The device is present or is assumed present if no _STA exists.
729      * Run the _INI if it exists (not required to exist)
730      *
731      * Note: We know there is an _INI within this subtree, but it may not be
732      * under this particular device, it may be lower in the branch.
733      */
734     if (!ACPI_COMPARE_NAME (DeviceNode->Name.Ascii, "_SB_") ||
735         DeviceNode->Parent != AcpiGbl_RootNode)
736     {
737         ACPI_DEBUG_EXEC (AcpiUtDisplayInitPathname (
738             ACPI_TYPE_METHOD, DeviceNode, METHOD_NAME__INI));
739 
740         memset (Info, 0, sizeof (ACPI_EVALUATE_INFO));
741         Info->PrefixNode = DeviceNode;
742         Info->RelativePathname = METHOD_NAME__INI;
743         Info->Parameters = NULL;
744         Info->Flags = ACPI_IGNORE_RETURN_VALUE;
745 
746         Status = AcpiNsEvaluate (Info);
747         if (ACPI_SUCCESS (Status))
748         {
749             WalkInfo->Num_INI++;
750         }
751 
752 #ifdef ACPI_DEBUG_OUTPUT
753         else if (Status != AE_NOT_FOUND)
754         {
755             /* Ignore error and move on to next device */
756 
757             char *ScopeName = AcpiNsGetNormalizedPathname (DeviceNode, TRUE);
758 
759             ACPI_EXCEPTION ((AE_INFO, Status, "during %s._INI execution",
760                 ScopeName));
761             ACPI_FREE (ScopeName);
762         }
763 #endif
764     }
765 
766     /* Ignore errors from above */
767 
768     Status = AE_OK;
769 
770     /*
771      * The _INI method has been run if present; call the Global Initialization
772      * Handler for this device.
773      */
774     if (AcpiGbl_InitHandler)
775     {
776         Status = AcpiGbl_InitHandler (DeviceNode, ACPI_INIT_DEVICE_INI);
777     }
778 
779     return_ACPI_STATUS (Status);
780 }
781