NetBSD-5.0.2/sys/dev/acpi/acpi_powerres.c
/* $NetBSD: acpi_powerres.c,v 1.6 2008/04/14 00:30:30 jmcneill Exp $ */
/*-
* Copyright (c) 2001 Michael Smith
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD: src/sys/dev/acpica/acpi_powerres.c,v 1.14 2002/10/16 17:28:52 jhb Exp $
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: acpi_powerres.c,v 1.6 2008/04/14 00:30:30 jmcneill Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/conf.h>
#include <sys/systm.h>
#include <dev/acpi/acpica.h>
#include <dev/acpi/acpireg.h>
#include <dev/acpi/acpivar.h>
/*
* ACPI power resource management.
*
* Power resource behaviour is slightly complicated by the fact that
* a single power resource may provide power for more than one device.
* Thus, we must track the device(s) being powered by a given power
* resource, and only deactivate it when there are no powered devices.
*
* Note that this only manages resources for known devices. There is an
* ugly case where we may turn of power to a device which is in use because
* we don't know that it depends on a given resource. We should perhaps
* try to be smarter about this, but a more complete solution would involve
* scanning all of the ACPI namespace to find devices we're not currently
* aware of, and this raises questions about whether they should be left
* on, turned off, etc.
*
* XXX locking
*/
MALLOC_DEFINE(M_ACPIPWR, "acpipwr", "ACPI power resources");
/*
* Hooks for the ACPI CA debugging infrastructure
*/
#define _COMPONENT ACPI_BUS_COMPONENT
ACPI_MODULE_NAME("POWERRES")
/*
* A relationship between a power resource and a consumer.
*/
struct acpi_powerreference {
struct acpi_powerconsumer *ar_consumer;
struct acpi_powerresource *ar_resource;
TAILQ_ENTRY(acpi_powerreference) ar_rlink; /* link on resource list */
TAILQ_ENTRY(acpi_powerreference) ar_clink; /* link on consumer */
};
/*
* A power-managed device.
*/
struct acpi_powerconsumer {
ACPI_HANDLE ac_consumer; /* device which is powered */
int ac_state;
TAILQ_ENTRY(acpi_powerconsumer) ac_link;
TAILQ_HEAD(,acpi_powerreference) ac_references;
};
/*
* A power resource.
*/
struct acpi_powerresource {
TAILQ_ENTRY(acpi_powerresource) ap_link;
TAILQ_HEAD(,acpi_powerreference) ap_references;
ACPI_HANDLE ap_resource; /* the resource's handle */
ACPI_INTEGER ap_systemlevel;
ACPI_INTEGER ap_order;
};
static TAILQ_HEAD(acpi_powerresource_list, acpi_powerresource)
acpi_powerresources = TAILQ_HEAD_INITIALIZER(acpi_powerresources);
static TAILQ_HEAD(acpi_powerconsumer_list, acpi_powerconsumer)
acpi_powerconsumers = TAILQ_HEAD_INITIALIZER(acpi_powerconsumers);
static ACPI_STATUS acpi_pwr_register_consumer(ACPI_HANDLE);
#if 0
static ACPI_STATUS acpi_pwr_register_resource(ACPI_HANDLE);
static ACPI_STATUS acpi_pwr_deregister_consumer(ACPI_HANDLE);
static ACPI_STATUS acpi_pwr_deregister_resource(ACPI_HANDLE);
#endif
static ACPI_STATUS acpi_pwr_reference_resource(ACPI_OBJECT *, void *);
static ACPI_STATUS acpi_pwr_switch_power(void);
static struct acpi_powerresource *acpi_pwr_find_resource(ACPI_HANDLE);
static struct acpi_powerconsumer *acpi_pwr_find_consumer(ACPI_HANDLE);
/*
* Register a power resource.
*
* It's OK to call this if we already know about the resource.
*/
static ACPI_STATUS
acpi_pwr_register_resource(ACPI_HANDLE res)
{
ACPI_STATUS status;
ACPI_BUFFER buf;
ACPI_OBJECT *obj;
struct acpi_powerresource *rp, *srp;
ACPI_FUNCTION_TRACE(__func__);
rp = NULL;
buf.Pointer = NULL;
/* look to see if we know about this resource */
if (acpi_pwr_find_resource(res) != NULL)
return_ACPI_STATUS(AE_OK); /* already know about it */
/* allocate a new resource */
if ((rp = malloc(sizeof(*rp), M_ACPIPWR, M_NOWAIT | M_ZERO)) == NULL) {
status = AE_NO_MEMORY;
goto out;
}
TAILQ_INIT(&rp->ap_references);
rp->ap_resource = res;
/* get the Power Resource object */
buf.Length = ACPI_ALLOCATE_BUFFER;
status = AcpiEvaluateObject(res, NULL, NULL, &buf);
if (ACPI_FAILURE(status)) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS,
"no power resource object\n"));
goto out;
}
obj = buf.Pointer;
if (obj->Type != ACPI_TYPE_POWER) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS,
"questionable power resource object %s\n",
acpi_name(res)));
status = AE_TYPE;
goto out;
}
rp->ap_systemlevel = obj->PowerResource.SystemLevel;
rp->ap_order = obj->PowerResource.ResourceOrder;
/* sort the resource into the list */
status = AE_OK;
srp = TAILQ_FIRST(&acpi_powerresources);
if ((srp == NULL) || (rp->ap_order < srp->ap_order)) {
TAILQ_INSERT_HEAD(&acpi_powerresources, rp, ap_link);
goto done;
}
TAILQ_FOREACH(srp, &acpi_powerresources, ap_link)
if (rp->ap_order < srp->ap_order) {
TAILQ_INSERT_BEFORE(srp, rp, ap_link);
goto done;
}
TAILQ_INSERT_TAIL(&acpi_powerresources, rp, ap_link);
done:
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "registered power resource %s\n",
acpi_name(res)));
out:
if (buf.Pointer != NULL)
AcpiOsFree(buf.Pointer);
if (ACPI_FAILURE(status) && (rp != NULL))
free(rp, M_ACPIPWR);
return_ACPI_STATUS(status);
}
#if 0
/*
* Deregister a power resource.
*/
static ACPI_STATUS
acpi_pwr_deregister_resource(ACPI_HANDLE res)
{
struct acpi_powerresource *rp;
ACPI_FUNCTION_TRACE(__func__);
rp = NULL;
/* find the resource */
if ((rp = acpi_pwr_find_resource(res)) == NULL)
return_ACPI_STATUS(AE_BAD_PARAMETER);
/* check that there are no consumers referencing this resource */
if (TAILQ_FIRST(&rp->ap_references) != NULL)
return_ACPI_STATUS(AE_BAD_PARAMETER);
/* pull it off the list and free it */
TAILQ_REMOVE(&acpi_powerresources, rp, ap_link);
free(rp, M_ACPIPWR);
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "deregistered power resource %s\n",
acpi_name(res)));
return_ACPI_STATUS(AE_OK);
}
#endif
/*
* Register a power consumer.
*
* It's OK to call this if we already know about the consumer.
*/
static ACPI_STATUS
acpi_pwr_register_consumer(ACPI_HANDLE consumer)
{
struct acpi_powerconsumer *pc;
ACPI_FUNCTION_TRACE(__func__);
/* check to see whether we know about this consumer already */
if ((pc = acpi_pwr_find_consumer(consumer)) != NULL)
return_ACPI_STATUS(AE_OK);
/* allocate a new power consumer */
if ((pc = malloc(sizeof(*pc), M_ACPIPWR, M_NOWAIT)) == NULL)
return_ACPI_STATUS(AE_NO_MEMORY);
TAILQ_INSERT_HEAD(&acpi_powerconsumers, pc, ac_link);
TAILQ_INIT(&pc->ac_references);
pc->ac_consumer = consumer;
/* XXX we should try to find its current state */
pc->ac_state = ACPI_STATE_UNKNOWN;
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "registered power consumer %s\n",
acpi_name(consumer)));
return_ACPI_STATUS(AE_OK);
}
#if 0
/*
* Deregister a power consumer.
*
* This should only be done once the consumer has been powered off.
* (XXX is this correct? Check once implemented)
*/
static ACPI_STATUS
acpi_pwr_deregister_consumer(ACPI_HANDLE consumer)
{
struct acpi_powerconsumer *pc;
ACPI_FUNCTION_TRACE(__func__);
/* find the consumer */
if ((pc = acpi_pwr_find_consumer(consumer)) == NULL)
return_ACPI_STATUS(AE_BAD_PARAMETER);
/* make sure the consumer's not referencing anything right now */
if (TAILQ_FIRST(&pc->ac_references) != NULL)
return_ACPI_STATUS(AE_BAD_PARAMETER);
/* pull the consumer off the list and free it */
TAILQ_REMOVE(&acpi_powerconsumers, pc, ac_link);
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "deregistered power consumer %s\n",
acpi_name(consumer)));
return_ACPI_STATUS(AE_OK);
}
#endif
/*
* Set a power consumer to a particular power state.
*/
ACPI_STATUS
acpi_pwr_switch_consumer(ACPI_HANDLE consumer, int state)
{
struct acpi_powerconsumer *pc;
struct acpi_powerreference *pr;
ACPI_HANDLE method_handle, reslist_handle, pr0_handle;
ACPI_BUFFER reslist_buffer;
ACPI_OBJECT *reslist_object;
ACPI_STATUS status;
const char *method_name, *reslist_name;
int res_changed;
ACPI_FUNCTION_TRACE(__func__);
/* find the consumer */
if ((pc = acpi_pwr_find_consumer(consumer)) == NULL) {
status = acpi_pwr_register_consumer(consumer);
if (ACPI_FAILURE(status))
return_ACPI_STATUS(status);
if ((pc = acpi_pwr_find_consumer(consumer)) == NULL) {
return_ACPI_STATUS(AE_ERROR); /* something very wrong */
}
}
/* check for valid transitions */
if ((pc->ac_state == ACPI_STATE_D3) && (state != ACPI_STATE_D0))
return_ACPI_STATUS(AE_BAD_PARAMETER); /* can only go to D0 from D3 */
/* find transition mechanism(s) */
switch(state) {
case ACPI_STATE_D0:
method_name = "_PS0";
reslist_name = "_PR0";
break;
case ACPI_STATE_D1:
method_name = "_PS1";
reslist_name = "_PR1";
break;
case ACPI_STATE_D2:
method_name = "_PS2";
reslist_name = "_PR2";
break;
case ACPI_STATE_D3:
method_name = "_PS3";
reslist_name = "_PR3";
break;
default:
return_ACPI_STATUS(AE_BAD_PARAMETER);
}
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "setup to switch %s D%d -> D%d\n",
acpi_name(consumer), pc->ac_state, state));
/*
* Verify that this state is supported, ie. one of method or
* reslist must be present. We need to do this before we go
* dereferencing resources (since we might be trying to go to
* a state we don't support).
*
* Note that if any states are supported, the device has to
* support D0 and D3. It's never an error to try to go to
* D0.
*/
reslist_buffer.Pointer = NULL;
reslist_object = NULL;
if (ACPI_FAILURE(AcpiGetHandle(consumer, method_name, &method_handle)))
method_handle = NULL;
if (ACPI_FAILURE(AcpiGetHandle(consumer, reslist_name, &reslist_handle)))
reslist_handle = NULL;
if ((reslist_handle == NULL) && (method_handle == NULL)) {
if (state == ACPI_STATE_D0) {
pc->ac_state = ACPI_STATE_D0;
return_ACPI_STATUS(AE_OK);
}
if (state != ACPI_STATE_D3) {
goto bad;
}
/* turn off the resources listed in _PR0 to go to D3. */
if (ACPI_FAILURE(AcpiGetHandle(consumer, "_PR0", &pr0_handle))) {
goto bad;
}
reslist_buffer.Length = ACPI_ALLOCATE_BUFFER;
status = AcpiEvaluateObject(pr0_handle, NULL, NULL, &reslist_buffer);
if (ACPI_FAILURE(status))
goto bad;
reslist_object = (ACPI_OBJECT *)reslist_buffer.Pointer;
if ((reslist_object->Type != ACPI_TYPE_PACKAGE) ||
(reslist_object->Package.Count == 0)) {
goto bad;
}
AcpiOsFree(reslist_buffer.Pointer);
reslist_buffer.Pointer = NULL;
reslist_object = NULL;
}
/*
* Check that we can actually fetch the list of power resources
*/
if (reslist_handle != NULL) {
reslist_buffer.Length = ACPI_ALLOCATE_BUFFER;
status = AcpiEvaluateObject(reslist_handle, NULL, NULL,
&reslist_buffer);
if (ACPI_FAILURE(status)) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "can't evaluate resource list %s\n",
acpi_name(reslist_handle)));
goto out;
}
reslist_object = (ACPI_OBJECT *)reslist_buffer.Pointer;
if (reslist_object->Type != ACPI_TYPE_PACKAGE) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "resource list is not ACPI_TYPE_PACKAGE (%d)\n",
reslist_object->Type));
status = AE_TYPE;
goto out;
}
}
/*
* Now we are ready to switch, so kill off any current power resource references.
*/
res_changed = 0;
while((pr = TAILQ_FIRST(&pc->ac_references)) != NULL) {
res_changed = 1;
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS,
"removing reference to %s\n",
acpi_name(pr->ar_resource->ap_resource)));
TAILQ_REMOVE(&pr->ar_resource->ap_references, pr, ar_rlink);
TAILQ_REMOVE(&pc->ac_references, pr, ar_clink);
free(pr, M_ACPIPWR);
}
/*
* Add new power resource references, if we have any. Traverse the
* package that we got from evaluating reslist_handle, and look up each
* of the resources that are referenced.
*/
if (reslist_object != NULL) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS,
"referencing %d new resources\n",
reslist_object->Package.Count));
acpi_foreach_package_object(reslist_object,
acpi_pwr_reference_resource, pc);
res_changed = 1;
}
/*
* If we changed anything in the resource list, we need to run a switch
* pass now.
*/
status = acpi_pwr_switch_power();
if (ACPI_FAILURE(status)) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "failed to correctly switch resources to move %s to D%d\n",
acpi_name(consumer), state));
goto out; /* XXX is this appropriate? Should we return to previous state? */
}
/* invoke power state switch method (if present) */
if (method_handle != NULL) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS,
"invoking state transition method %s\n",
acpi_name(method_handle)));
status = AcpiEvaluateObject(method_handle, NULL, NULL, NULL);
if (ACPI_FAILURE(status)) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS,
"failed to set state - %s\n",
AcpiFormatException(status)));
pc->ac_state = ACPI_STATE_UNKNOWN;
goto out; /* XXX Should we return to previous state? */
}
}
/* transition was successful */
pc->ac_state = state;
return_ACPI_STATUS(AE_OK);
bad:
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS,
"attempt to set unsupported state D%d\n",
state));
status = AE_BAD_PARAMETER;
out:
if (reslist_buffer.Pointer != NULL)
AcpiOsFree(reslist_buffer.Pointer);
return_ACPI_STATUS(status);
}
/*
* Called to create a reference between a power consumer and a power resource
* identified in the object.
*/
static ACPI_STATUS
acpi_pwr_reference_resource(ACPI_OBJECT *obj, void *arg)
{
struct acpi_powerconsumer *pc = (struct acpi_powerconsumer *)arg;
struct acpi_powerreference *pr;
struct acpi_powerresource *rp;
ACPI_HANDLE res;
ACPI_STATUS status;
ACPI_FUNCTION_TRACE(__func__);
/* check the object type */
switch (obj->Type) {
case ACPI_TYPE_LOCAL_REFERENCE:
case ACPI_TYPE_ANY:
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "building reference from %s to %s\n",
acpi_name(pc->ac_consumer), acpi_name(obj->Reference.Handle)));
res = obj->Reference.Handle;
break;
case ACPI_TYPE_STRING:
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS,
"building reference from %s to %s\n",
acpi_name(pc->ac_consumer),
obj->String.Pointer));
/* get the handle of the resource */
status = AcpiGetHandle(NULL, obj->String.Pointer, &res);
if (ACPI_FAILURE(status)) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS,
"couldn't find power resource %s\n",
obj->String.Pointer));
return_ACPI_STATUS(AE_OK);
}
break;
default:
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS,
"don't know how to create a power reference to object type %d\n",
obj->Type));
return_ACPI_STATUS(AE_OK);
}
/* create/look up the resource */
status = acpi_pwr_register_resource(res);
if (ACPI_FAILURE(status)) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS,
"couldn't register power resource %s - %s\n",
obj->String.Pointer,
AcpiFormatException(status)));
return_ACPI_STATUS(AE_OK);
}
if ((rp = acpi_pwr_find_resource(res)) == NULL) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS,
"power resource list corrupted\n"));
return_ACPI_STATUS(AE_OK);
}
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "found power resource %s\n",
acpi_name(rp->ap_resource)));
/* create a reference between the consumer and resource */
if ((pr = malloc(sizeof(*pr), M_ACPIPWR, M_NOWAIT | M_ZERO)) == NULL) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "couldn't allocate memory for a power consumer reference\n"));
return_ACPI_STATUS(AE_OK);
}
pr->ar_consumer = pc;
pr->ar_resource = rp;
TAILQ_INSERT_TAIL(&pc->ac_references, pr, ar_clink);
TAILQ_INSERT_TAIL(&rp->ap_references, pr, ar_rlink);
return_ACPI_STATUS(AE_OK);
}
/*
* Switch power resources to conform to the desired state.
*
* Consumers may have modified the power resource list in an arbitrary
* fashion; we sweep it in sequence order.
*/
static ACPI_STATUS
acpi_pwr_switch_power(void)
{
struct acpi_powerresource *rp;
ACPI_STATUS status;
ACPI_INTEGER cur;
ACPI_FUNCTION_TRACE(__func__);
/*
* Sweep the list forwards turning things on.
*/
TAILQ_FOREACH(rp, &acpi_powerresources, ap_link) {
if (TAILQ_FIRST(&rp->ap_references) == NULL) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "%s has no references, not turning on\n",
acpi_name(rp->ap_resource)));
continue;
}
/* we could cache this if we trusted it not to change under us */
status = acpi_eval_integer(rp->ap_resource, "_STA", &cur);
if (ACPI_FAILURE(status)) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS,
"can't get status of %s - %d\n",
acpi_name(rp->ap_resource),
status));
/* XXX is this correct? Always switch if in doubt? */
continue;
}
/*
* Switch if required. Note that we ignore the result
* of the switch effort; we don't know what to do if
* it fails, so checking wouldn't help much.
*/
if (cur != ACPI_STA_POW_ON) {
status = AcpiEvaluateObject(rp->ap_resource, "_ON",
NULL, NULL);
if (ACPI_FAILURE(status)) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "failed to switch %s on - %s\n",
acpi_name(rp->ap_resource),
AcpiFormatException(status)));
} else {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "switched %s on\n", acpi_name(rp->ap_resource)));
}
} else {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS,
"%s is already on\n",
acpi_name(rp->ap_resource)));
}
}
/*
* Sweep the list backwards turning things off.
*/
TAILQ_FOREACH_REVERSE(rp, &acpi_powerresources, acpi_powerresource_list, ap_link) {
if (TAILQ_FIRST(&rp->ap_references) != NULL) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "%s has references, not turning off\n",
acpi_name(rp->ap_resource)));
continue;
}
/* we could cache this if we trusted it not to change under us */
status = acpi_eval_integer(rp->ap_resource, "_STA", &cur);
if (ACPI_FAILURE(status)) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "can't get status of %s - %d\n",
acpi_name(rp->ap_resource), status));
continue; /* XXX is this correct? Always switch if in doubt? */
}
/*
* Switch if required. Note that we ignore the result
* of the switch effort; we don't know what to do if
* it fails, so checking wouldn't help much.
*/
if (cur != ACPI_STA_POW_OFF) {
status = AcpiEvaluateObject(rp->ap_resource, "_OFF",
NULL, NULL);
if (ACPI_FAILURE(status)) {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "failed to switch %s off - %s\n",
acpi_name(rp->ap_resource), AcpiFormatException(status)));
} else {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "switched %s off\n",
acpi_name(rp->ap_resource)));
}
} else {
ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "%s is already off\n",
acpi_name(rp->ap_resource)));
}
}
return_ACPI_STATUS(AE_OK);
}
/*
* Find a power resource's control structure.
*/
static struct acpi_powerresource *
acpi_pwr_find_resource(ACPI_HANDLE res)
{
struct acpi_powerresource *rp;
ACPI_FUNCTION_TRACE(__func__);
TAILQ_FOREACH(rp, &acpi_powerresources, ap_link)
if (rp->ap_resource == res)
break;
return_PTR(rp);
}
/*
* Find a power consumer's control structure.
*/
static struct acpi_powerconsumer *
acpi_pwr_find_consumer(ACPI_HANDLE consumer)
{
struct acpi_powerconsumer *pc;
ACPI_FUNCTION_TRACE(__func__);
TAILQ_FOREACH(pc, &acpi_powerconsumers, ac_link)
if (pc->ac_consumer == consumer)
break;
return_PTR(pc);
}