![Rafael J. Wysocki](/assets/img/avatar_default.png)
The reference counting of ACPI power resources is currently broken for a few reasons. First, instead of using a simple reference counter per power resource it uses a list of objects representing refereces to the given power resource from devices. This leads to the second breakage, because it prevents power resources from being referenced more than once by one device, which is necessary if the device is configured to signal wakeup. Namely, when putting the device into a low power state we first call acpi_enable_wakeup_device_power() that should reference count power resources needed for signaling wakeup and then we call acpi_power_transition() to power off the device. The latter call drops references to the device's power resources, possibly including the ones added by acpi_enable_wakeup_device_power(), so the device can't signal wakeup as a result. Apart from this, the locking in acpi_power_on() and acpi_power_off_device() doesn't prevent all possible races from happening, which may be problematic for runtime PM and asynchronous suspend and resume. Fix the problem by using a counter for power resources reference counting and putting the evaluation of ACPI _ON and _OFF methods under the power resource mutex. Reported-by: Matthew Garrett <mjg@redhat.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
625 lines
16 KiB
C
625 lines
16 KiB
C
/*
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* acpi_power.c - ACPI Bus Power Management ($Revision: 39 $)
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*
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* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
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* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
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*
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or (at
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* your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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*
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*/
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/*
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* ACPI power-managed devices may be controlled in two ways:
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* 1. via "Device Specific (D-State) Control"
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* 2. via "Power Resource Control".
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* This module is used to manage devices relying on Power Resource Control.
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*
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* An ACPI "power resource object" describes a software controllable power
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* plane, clock plane, or other resource used by a power managed device.
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* A device may rely on multiple power resources, and a power resource
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* may be shared by multiple devices.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/types.h>
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#include <linux/slab.h>
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#include <acpi/acpi_bus.h>
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#include <acpi/acpi_drivers.h>
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#include "sleep.h"
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#define PREFIX "ACPI: "
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#define _COMPONENT ACPI_POWER_COMPONENT
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ACPI_MODULE_NAME("power");
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#define ACPI_POWER_CLASS "power_resource"
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#define ACPI_POWER_DEVICE_NAME "Power Resource"
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#define ACPI_POWER_FILE_INFO "info"
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#define ACPI_POWER_FILE_STATUS "state"
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#define ACPI_POWER_RESOURCE_STATE_OFF 0x00
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#define ACPI_POWER_RESOURCE_STATE_ON 0x01
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#define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF
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int acpi_power_nocheck;
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module_param_named(power_nocheck, acpi_power_nocheck, bool, 000);
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static int acpi_power_add(struct acpi_device *device);
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static int acpi_power_remove(struct acpi_device *device, int type);
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static int acpi_power_resume(struct acpi_device *device);
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static const struct acpi_device_id power_device_ids[] = {
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{ACPI_POWER_HID, 0},
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{"", 0},
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};
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MODULE_DEVICE_TABLE(acpi, power_device_ids);
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static struct acpi_driver acpi_power_driver = {
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.name = "power",
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.class = ACPI_POWER_CLASS,
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.ids = power_device_ids,
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.ops = {
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.add = acpi_power_add,
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.remove = acpi_power_remove,
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.resume = acpi_power_resume,
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},
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};
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struct acpi_power_resource {
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struct acpi_device * device;
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acpi_bus_id name;
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u32 system_level;
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u32 order;
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unsigned int ref_count;
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struct mutex resource_lock;
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};
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static struct list_head acpi_power_resource_list;
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/* --------------------------------------------------------------------------
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Power Resource Management
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-------------------------------------------------------------------------- */
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static int
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acpi_power_get_context(acpi_handle handle,
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struct acpi_power_resource **resource)
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{
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int result = 0;
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struct acpi_device *device = NULL;
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if (!resource)
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return -ENODEV;
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result = acpi_bus_get_device(handle, &device);
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if (result) {
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printk(KERN_WARNING PREFIX "Getting context [%p]\n", handle);
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return result;
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}
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*resource = acpi_driver_data(device);
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if (!*resource)
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return -ENODEV;
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return 0;
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}
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static int acpi_power_get_state(acpi_handle handle, int *state)
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{
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acpi_status status = AE_OK;
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unsigned long long sta = 0;
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char node_name[5];
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struct acpi_buffer buffer = { sizeof(node_name), node_name };
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if (!handle || !state)
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return -EINVAL;
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status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
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if (ACPI_FAILURE(status))
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return -ENODEV;
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*state = (sta & 0x01)?ACPI_POWER_RESOURCE_STATE_ON:
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ACPI_POWER_RESOURCE_STATE_OFF;
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acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
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ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] is %s\n",
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node_name,
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*state ? "on" : "off"));
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return 0;
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}
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static int acpi_power_get_list_state(struct acpi_handle_list *list, int *state)
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{
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int result = 0, state1;
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u32 i = 0;
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if (!list || !state)
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return -EINVAL;
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/* The state of the list is 'on' IFF all resources are 'on'. */
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for (i = 0; i < list->count; i++) {
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/*
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* The state of the power resource can be obtained by
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* using the ACPI handle. In such case it is unnecessary to
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* get the Power resource first and then get its state again.
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*/
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result = acpi_power_get_state(list->handles[i], &state1);
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if (result)
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return result;
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*state = state1;
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if (*state != ACPI_POWER_RESOURCE_STATE_ON)
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break;
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}
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ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource list is %s\n",
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*state ? "on" : "off"));
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return result;
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}
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static int __acpi_power_on(struct acpi_power_resource *resource)
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{
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acpi_status status = AE_OK;
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status = acpi_evaluate_object(resource->device->handle, "_ON", NULL, NULL);
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if (ACPI_FAILURE(status))
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return -ENODEV;
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/* Update the power resource's _device_ power state */
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resource->device->power.state = ACPI_STATE_D0;
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ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned on\n",
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resource->name));
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return 0;
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}
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static int acpi_power_on(acpi_handle handle)
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{
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int result = 0;
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struct acpi_power_resource *resource = NULL;
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result = acpi_power_get_context(handle, &resource);
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if (result)
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return result;
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mutex_lock(&resource->resource_lock);
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if (resource->ref_count++) {
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ACPI_DEBUG_PRINT((ACPI_DB_INFO,
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"Power resource [%s] already on",
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resource->name));
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} else {
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result = __acpi_power_on(resource);
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}
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mutex_unlock(&resource->resource_lock);
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return 0;
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}
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static int acpi_power_off_device(acpi_handle handle)
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{
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int result = 0;
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acpi_status status = AE_OK;
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struct acpi_power_resource *resource = NULL;
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result = acpi_power_get_context(handle, &resource);
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if (result)
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return result;
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mutex_lock(&resource->resource_lock);
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if (!resource->ref_count) {
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ACPI_DEBUG_PRINT((ACPI_DB_INFO,
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"Power resource [%s] already off",
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resource->name));
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goto unlock;
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}
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if (--resource->ref_count) {
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ACPI_DEBUG_PRINT((ACPI_DB_INFO,
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"Power resource [%s] still in use\n",
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resource->name));
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goto unlock;
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}
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status = acpi_evaluate_object(resource->device->handle, "_OFF", NULL, NULL);
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if (ACPI_FAILURE(status)) {
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result = -ENODEV;
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} else {
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/* Update the power resource's _device_ power state */
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resource->device->power.state = ACPI_STATE_D3;
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ACPI_DEBUG_PRINT((ACPI_DB_INFO,
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"Power resource [%s] turned off\n",
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resource->name));
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}
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unlock:
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mutex_unlock(&resource->resource_lock);
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return result;
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}
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/**
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* acpi_device_sleep_wake - execute _DSW (Device Sleep Wake) or (deprecated in
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* ACPI 3.0) _PSW (Power State Wake)
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* @dev: Device to handle.
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* @enable: 0 - disable, 1 - enable the wake capabilities of the device.
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* @sleep_state: Target sleep state of the system.
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* @dev_state: Target power state of the device.
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*
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* Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
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* State Wake) for the device, if present. On failure reset the device's
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* wakeup.flags.valid flag.
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*
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* RETURN VALUE:
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* 0 if either _DSW or _PSW has been successfully executed
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* 0 if neither _DSW nor _PSW has been found
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* -ENODEV if the execution of either _DSW or _PSW has failed
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*/
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int acpi_device_sleep_wake(struct acpi_device *dev,
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int enable, int sleep_state, int dev_state)
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{
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union acpi_object in_arg[3];
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struct acpi_object_list arg_list = { 3, in_arg };
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acpi_status status = AE_OK;
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/*
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* Try to execute _DSW first.
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*
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* Three agruments are needed for the _DSW object:
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* Argument 0: enable/disable the wake capabilities
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* Argument 1: target system state
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* Argument 2: target device state
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* When _DSW object is called to disable the wake capabilities, maybe
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* the first argument is filled. The values of the other two agruments
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* are meaningless.
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*/
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in_arg[0].type = ACPI_TYPE_INTEGER;
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in_arg[0].integer.value = enable;
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in_arg[1].type = ACPI_TYPE_INTEGER;
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in_arg[1].integer.value = sleep_state;
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in_arg[2].type = ACPI_TYPE_INTEGER;
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in_arg[2].integer.value = dev_state;
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status = acpi_evaluate_object(dev->handle, "_DSW", &arg_list, NULL);
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if (ACPI_SUCCESS(status)) {
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return 0;
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} else if (status != AE_NOT_FOUND) {
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printk(KERN_ERR PREFIX "_DSW execution failed\n");
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dev->wakeup.flags.valid = 0;
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return -ENODEV;
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}
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/* Execute _PSW */
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arg_list.count = 1;
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in_arg[0].integer.value = enable;
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status = acpi_evaluate_object(dev->handle, "_PSW", &arg_list, NULL);
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if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
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printk(KERN_ERR PREFIX "_PSW execution failed\n");
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dev->wakeup.flags.valid = 0;
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return -ENODEV;
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}
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return 0;
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}
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/*
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* Prepare a wakeup device, two steps (Ref ACPI 2.0:P229):
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* 1. Power on the power resources required for the wakeup device
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* 2. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
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* State Wake) for the device, if present
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*/
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int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
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{
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int i, err = 0;
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if (!dev || !dev->wakeup.flags.valid)
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return -EINVAL;
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mutex_lock(&acpi_device_lock);
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if (dev->wakeup.prepare_count++)
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goto out;
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/* Open power resource */
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for (i = 0; i < dev->wakeup.resources.count; i++) {
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int ret = acpi_power_on(dev->wakeup.resources.handles[i]);
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if (ret) {
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printk(KERN_ERR PREFIX "Transition power state\n");
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dev->wakeup.flags.valid = 0;
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err = -ENODEV;
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goto err_out;
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}
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}
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/*
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* Passing 3 as the third argument below means the device may be placed
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* in arbitrary power state afterwards.
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*/
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err = acpi_device_sleep_wake(dev, 1, sleep_state, 3);
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err_out:
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if (err)
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dev->wakeup.prepare_count = 0;
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out:
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mutex_unlock(&acpi_device_lock);
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return err;
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}
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/*
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* Shutdown a wakeup device, counterpart of above method
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* 1. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
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* State Wake) for the device, if present
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* 2. Shutdown down the power resources
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*/
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int acpi_disable_wakeup_device_power(struct acpi_device *dev)
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{
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int i, err = 0;
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if (!dev || !dev->wakeup.flags.valid)
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return -EINVAL;
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mutex_lock(&acpi_device_lock);
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if (--dev->wakeup.prepare_count > 0)
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goto out;
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/*
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* Executing the code below even if prepare_count is already zero when
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* the function is called may be useful, for example for initialisation.
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*/
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if (dev->wakeup.prepare_count < 0)
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dev->wakeup.prepare_count = 0;
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err = acpi_device_sleep_wake(dev, 0, 0, 0);
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if (err)
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goto out;
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/* Close power resource */
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for (i = 0; i < dev->wakeup.resources.count; i++) {
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int ret = acpi_power_off_device(
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dev->wakeup.resources.handles[i]);
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if (ret) {
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printk(KERN_ERR PREFIX "Transition power state\n");
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dev->wakeup.flags.valid = 0;
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err = -ENODEV;
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goto out;
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}
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}
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out:
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mutex_unlock(&acpi_device_lock);
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return err;
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}
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/* --------------------------------------------------------------------------
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Device Power Management
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-------------------------------------------------------------------------- */
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int acpi_power_get_inferred_state(struct acpi_device *device)
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{
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int result = 0;
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struct acpi_handle_list *list = NULL;
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int list_state = 0;
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int i = 0;
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if (!device)
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return -EINVAL;
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device->power.state = ACPI_STATE_UNKNOWN;
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/*
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* We know a device's inferred power state when all the resources
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* required for a given D-state are 'on'.
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*/
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for (i = ACPI_STATE_D0; i < ACPI_STATE_D3; i++) {
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list = &device->power.states[i].resources;
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if (list->count < 1)
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continue;
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result = acpi_power_get_list_state(list, &list_state);
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if (result)
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return result;
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if (list_state == ACPI_POWER_RESOURCE_STATE_ON) {
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device->power.state = i;
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return 0;
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}
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}
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device->power.state = ACPI_STATE_D3;
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return 0;
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}
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int acpi_power_transition(struct acpi_device *device, int state)
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{
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int result = 0;
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struct acpi_handle_list *cl = NULL; /* Current Resources */
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struct acpi_handle_list *tl = NULL; /* Target Resources */
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int i = 0;
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if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3))
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return -EINVAL;
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if ((device->power.state < ACPI_STATE_D0)
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|| (device->power.state > ACPI_STATE_D3))
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return -ENODEV;
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cl = &device->power.states[device->power.state].resources;
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tl = &device->power.states[state].resources;
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/* TBD: Resources must be ordered. */
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/*
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* First we reference all power resources required in the target list
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* (e.g. so the device doesn't lose power while transitioning).
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*/
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for (i = 0; i < tl->count; i++) {
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result = acpi_power_on(tl->handles[i]);
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if (result)
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goto end;
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}
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if (device->power.state == state) {
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goto end;
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}
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/*
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* Then we dereference all power resources used in the current list.
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*/
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for (i = 0; i < cl->count; i++) {
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result = acpi_power_off_device(cl->handles[i]);
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if (result)
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goto end;
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}
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end:
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if (result)
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device->power.state = ACPI_STATE_UNKNOWN;
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else {
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/* We shouldn't change the state till all above operations succeed */
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device->power.state = state;
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}
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return result;
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}
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/* --------------------------------------------------------------------------
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Driver Interface
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-------------------------------------------------------------------------- */
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static int acpi_power_add(struct acpi_device *device)
|
|
{
|
|
int result = 0, state;
|
|
acpi_status status = AE_OK;
|
|
struct acpi_power_resource *resource = NULL;
|
|
union acpi_object acpi_object;
|
|
struct acpi_buffer buffer = { sizeof(acpi_object), &acpi_object };
|
|
|
|
|
|
if (!device)
|
|
return -EINVAL;
|
|
|
|
resource = kzalloc(sizeof(struct acpi_power_resource), GFP_KERNEL);
|
|
if (!resource)
|
|
return -ENOMEM;
|
|
|
|
resource->device = device;
|
|
mutex_init(&resource->resource_lock);
|
|
strcpy(resource->name, device->pnp.bus_id);
|
|
strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
|
|
strcpy(acpi_device_class(device), ACPI_POWER_CLASS);
|
|
device->driver_data = resource;
|
|
|
|
/* Evalute the object to get the system level and resource order. */
|
|
status = acpi_evaluate_object(device->handle, NULL, NULL, &buffer);
|
|
if (ACPI_FAILURE(status)) {
|
|
result = -ENODEV;
|
|
goto end;
|
|
}
|
|
resource->system_level = acpi_object.power_resource.system_level;
|
|
resource->order = acpi_object.power_resource.resource_order;
|
|
|
|
result = acpi_power_get_state(device->handle, &state);
|
|
if (result)
|
|
goto end;
|
|
|
|
switch (state) {
|
|
case ACPI_POWER_RESOURCE_STATE_ON:
|
|
device->power.state = ACPI_STATE_D0;
|
|
break;
|
|
case ACPI_POWER_RESOURCE_STATE_OFF:
|
|
device->power.state = ACPI_STATE_D3;
|
|
break;
|
|
default:
|
|
device->power.state = ACPI_STATE_UNKNOWN;
|
|
break;
|
|
}
|
|
|
|
printk(KERN_INFO PREFIX "%s [%s] (%s)\n", acpi_device_name(device),
|
|
acpi_device_bid(device), state ? "on" : "off");
|
|
|
|
end:
|
|
if (result)
|
|
kfree(resource);
|
|
|
|
return result;
|
|
}
|
|
|
|
static int acpi_power_remove(struct acpi_device *device, int type)
|
|
{
|
|
struct acpi_power_resource *resource;
|
|
|
|
if (!device)
|
|
return -EINVAL;
|
|
|
|
resource = acpi_driver_data(device);
|
|
if (!resource)
|
|
return -EINVAL;
|
|
|
|
kfree(resource);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int acpi_power_resume(struct acpi_device *device)
|
|
{
|
|
int result = 0, state;
|
|
struct acpi_power_resource *resource;
|
|
|
|
if (!device)
|
|
return -EINVAL;
|
|
|
|
resource = acpi_driver_data(device);
|
|
if (!resource)
|
|
return -EINVAL;
|
|
|
|
mutex_lock(&resource->resource_lock);
|
|
|
|
result = acpi_power_get_state(device->handle, &state);
|
|
if (result)
|
|
goto unlock;
|
|
|
|
if (state == ACPI_POWER_RESOURCE_STATE_OFF && resource->ref_count)
|
|
result = __acpi_power_on(resource);
|
|
|
|
unlock:
|
|
mutex_unlock(&resource->resource_lock);
|
|
|
|
return result;
|
|
}
|
|
|
|
int __init acpi_power_init(void)
|
|
{
|
|
INIT_LIST_HEAD(&acpi_power_resource_list);
|
|
return acpi_bus_register_driver(&acpi_power_driver);
|
|
}
|