linux/drivers/acpi/button.c
Lv Zheng dfa46c50f6 ACPI / button: Fix an issue in button.lid_init_state=ignore mode
On most platforms, _LID returning value, lid open/close events are all
reliable, but there are exceptions. Some AML tables report wrong initial
lid state [1], and some of them never report lid open state [2].
The usage model on such buggy platforms is:
1. The initial lid state returned from _LID is not reliable;
2. The lid open event is not reliable;
3. The lid close event is always reliable, used by the platform firmware to
   trigger OSPM power saving operations.
This usage model is not compliant to the Linux SW_LID model as the Linux
userspace is very strict to the reliability of the open events.

In order not to trigger issues on such buggy platforms, the ACPI button
driver currently implements a lid_init_state=open quirk to send additional
"open" event after resuming. However, this is still not sufficient because:
1. Some special usage models (e.x., the dark resume scenario) cannot be
   supported by this mode.
2. If a "close" event is not used to trigger "suspend", then the subsequent
   "close" events cannot be seen by the userspace.
So we need to stop sending the additional "open" event and switch the
driver to lid_init_state=ignore mode and make sure the platform triggered
events can be reliably delivered to the userspace. The userspace programs
then can be changed to not to be strict to the "open" events on such buggy
platforms.

Why will the subsequent "close" events be lost? This is because the input
layer automatically filters redundant events for switch events. Thus given
that the buggy AML tables do not guarantee paired "open"/"close" events,
the ACPI button driver currently is not able to guarantee that the platform
triggered reliable events can be always be seen by the userspace via
SW_LID.

This patch adds a mechanism to insert lid events as a compensation for the
platform triggered ones to form a complete event switches in order to make
sure that the platform triggered events can always be reliably delivered
to the userspace. This essentially guarantees that the platform triggered
reliable "close" events will always be relibly delivered to the userspace.

However this mechanism is not suitable for lid_init_state=open/method as
it should not send the complement switch event for the unreliable initial
lid state notification. 2 unreliable events can trigger unexpected
behavior. Thus this patch only implements this mechanism for
lid_init_state=ignore.

Known issues:
1. Possible alternative approach
   This approach is based on the fact that Linux requires a switch event
   type for LID events. Another approach is to use key event type to
   implement ACPI lid events.
   With SW event type, since ACPI button driver inserts wrong lid events,
   there could be a potential issue that an "open" event issued from some
   AML update methods could result in a wrong "close" event to be delivered
   to the userspace. While using KEY event type, there is no such problem.
   However there may not be such a kind of real case, and if there is such
   a case, it is worked around in this patch as the complement switch event
   is only generated for "close" event in order to deliver the reliable
   "close" event to the userspace.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=89211 # [1]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=106151 # [1]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=106941 # [2]
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Suggested-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-08-31 01:06:20 +02:00

598 lines
16 KiB
C

/*
* button.c - ACPI Button Driver
*
* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#define pr_fmt(fmt) "ACPI : button: " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/input.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <acpi/button.h>
#define PREFIX "ACPI: "
#define ACPI_BUTTON_CLASS "button"
#define ACPI_BUTTON_FILE_INFO "info"
#define ACPI_BUTTON_FILE_STATE "state"
#define ACPI_BUTTON_TYPE_UNKNOWN 0x00
#define ACPI_BUTTON_NOTIFY_STATUS 0x80
#define ACPI_BUTTON_SUBCLASS_POWER "power"
#define ACPI_BUTTON_HID_POWER "PNP0C0C"
#define ACPI_BUTTON_DEVICE_NAME_POWER "Power Button"
#define ACPI_BUTTON_TYPE_POWER 0x01
#define ACPI_BUTTON_SUBCLASS_SLEEP "sleep"
#define ACPI_BUTTON_HID_SLEEP "PNP0C0E"
#define ACPI_BUTTON_DEVICE_NAME_SLEEP "Sleep Button"
#define ACPI_BUTTON_TYPE_SLEEP 0x03
#define ACPI_BUTTON_SUBCLASS_LID "lid"
#define ACPI_BUTTON_HID_LID "PNP0C0D"
#define ACPI_BUTTON_DEVICE_NAME_LID "Lid Switch"
#define ACPI_BUTTON_TYPE_LID 0x05
#define ACPI_BUTTON_LID_INIT_IGNORE 0x00
#define ACPI_BUTTON_LID_INIT_OPEN 0x01
#define ACPI_BUTTON_LID_INIT_METHOD 0x02
#define _COMPONENT ACPI_BUTTON_COMPONENT
ACPI_MODULE_NAME("button");
MODULE_AUTHOR("Paul Diefenbaugh");
MODULE_DESCRIPTION("ACPI Button Driver");
MODULE_LICENSE("GPL");
static const struct acpi_device_id button_device_ids[] = {
{ACPI_BUTTON_HID_LID, 0},
{ACPI_BUTTON_HID_SLEEP, 0},
{ACPI_BUTTON_HID_SLEEPF, 0},
{ACPI_BUTTON_HID_POWER, 0},
{ACPI_BUTTON_HID_POWERF, 0},
{"", 0},
};
MODULE_DEVICE_TABLE(acpi, button_device_ids);
static int acpi_button_add(struct acpi_device *device);
static int acpi_button_remove(struct acpi_device *device);
static void acpi_button_notify(struct acpi_device *device, u32 event);
#ifdef CONFIG_PM_SLEEP
static int acpi_button_suspend(struct device *dev);
static int acpi_button_resume(struct device *dev);
#else
#define acpi_button_suspend NULL
#define acpi_button_resume NULL
#endif
static SIMPLE_DEV_PM_OPS(acpi_button_pm, acpi_button_suspend, acpi_button_resume);
static struct acpi_driver acpi_button_driver = {
.name = "button",
.class = ACPI_BUTTON_CLASS,
.ids = button_device_ids,
.ops = {
.add = acpi_button_add,
.remove = acpi_button_remove,
.notify = acpi_button_notify,
},
.drv.pm = &acpi_button_pm,
};
struct acpi_button {
unsigned int type;
struct input_dev *input;
char phys[32]; /* for input device */
unsigned long pushed;
int last_state;
ktime_t last_time;
bool suspended;
};
static BLOCKING_NOTIFIER_HEAD(acpi_lid_notifier);
static struct acpi_device *lid_device;
static u8 lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
static unsigned long lid_report_interval __read_mostly = 500;
module_param(lid_report_interval, ulong, 0644);
MODULE_PARM_DESC(lid_report_interval, "Interval (ms) between lid key events");
/* --------------------------------------------------------------------------
FS Interface (/proc)
-------------------------------------------------------------------------- */
static struct proc_dir_entry *acpi_button_dir;
static struct proc_dir_entry *acpi_lid_dir;
static int acpi_lid_evaluate_state(struct acpi_device *device)
{
unsigned long long lid_state;
acpi_status status;
status = acpi_evaluate_integer(device->handle, "_LID", NULL, &lid_state);
if (ACPI_FAILURE(status))
return -ENODEV;
return lid_state ? 1 : 0;
}
static int acpi_lid_notify_state(struct acpi_device *device, int state)
{
struct acpi_button *button = acpi_driver_data(device);
int ret;
ktime_t next_report;
bool do_update;
/*
* In lid_init_state=ignore mode, if user opens/closes lid
* frequently with "open" missing, and "last_time" is also updated
* frequently, "close" cannot be delivered to the userspace.
* So "last_time" is only updated after a timeout or an actual
* switch.
*/
if (lid_init_state != ACPI_BUTTON_LID_INIT_IGNORE ||
button->last_state != !!state)
do_update = true;
else
do_update = false;
next_report = ktime_add(button->last_time,
ms_to_ktime(lid_report_interval));
if (button->last_state == !!state &&
ktime_after(ktime_get(), next_report)) {
/* Complain the buggy firmware */
pr_warn_once("The lid device is not compliant to SW_LID.\n");
/*
* Send the unreliable complement switch event:
*
* On most platforms, the lid device is reliable. However
* there are exceptions:
* 1. Platforms returning initial lid state as "close" by
* default after booting/resuming:
* https://bugzilla.kernel.org/show_bug.cgi?id=89211
* https://bugzilla.kernel.org/show_bug.cgi?id=106151
* 2. Platforms never reporting "open" events:
* https://bugzilla.kernel.org/show_bug.cgi?id=106941
* On these buggy platforms, the usage model of the ACPI
* lid device actually is:
* 1. The initial returning value of _LID may not be
* reliable.
* 2. The open event may not be reliable.
* 3. The close event is reliable.
*
* But SW_LID is typed as input switch event, the input
* layer checks if the event is redundant. Hence if the
* state is not switched, the userspace cannot see this
* platform triggered reliable event. By inserting a
* complement switch event, it then is guaranteed that the
* platform triggered reliable one can always be seen by
* the userspace.
*/
if (lid_init_state == ACPI_BUTTON_LID_INIT_IGNORE) {
do_update = true;
/*
* Do generate complement switch event for "close"
* as "close" is reliable and wrong "open" won't
* trigger unexpected behaviors.
* Do not generate complement switch event for
* "open" as "open" is not reliable and wrong
* "close" will trigger unexpected behaviors.
*/
if (!state) {
input_report_switch(button->input,
SW_LID, state);
input_sync(button->input);
}
}
}
/* Send the platform triggered reliable event */
if (do_update) {
input_report_switch(button->input, SW_LID, !state);
input_sync(button->input);
button->last_state = !!state;
button->last_time = ktime_get();
}
if (state)
pm_wakeup_event(&device->dev, 0);
ret = blocking_notifier_call_chain(&acpi_lid_notifier, state, device);
if (ret == NOTIFY_DONE)
ret = blocking_notifier_call_chain(&acpi_lid_notifier, state,
device);
if (ret == NOTIFY_DONE || ret == NOTIFY_OK) {
/*
* It is also regarded as success if the notifier_chain
* returns NOTIFY_OK or NOTIFY_DONE.
*/
ret = 0;
}
return ret;
}
static int acpi_button_state_seq_show(struct seq_file *seq, void *offset)
{
struct acpi_device *device = seq->private;
int state;
state = acpi_lid_evaluate_state(device);
seq_printf(seq, "state: %s\n",
state < 0 ? "unsupported" : (state ? "open" : "closed"));
return 0;
}
static int acpi_button_state_open_fs(struct inode *inode, struct file *file)
{
return single_open(file, acpi_button_state_seq_show, PDE_DATA(inode));
}
static const struct file_operations acpi_button_state_fops = {
.owner = THIS_MODULE,
.open = acpi_button_state_open_fs,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int acpi_button_add_fs(struct acpi_device *device)
{
struct acpi_button *button = acpi_driver_data(device);
struct proc_dir_entry *entry = NULL;
int ret = 0;
/* procfs I/F for ACPI lid device only */
if (button->type != ACPI_BUTTON_TYPE_LID)
return 0;
if (acpi_button_dir || acpi_lid_dir) {
printk(KERN_ERR PREFIX "More than one Lid device found!\n");
return -EEXIST;
}
/* create /proc/acpi/button */
acpi_button_dir = proc_mkdir(ACPI_BUTTON_CLASS, acpi_root_dir);
if (!acpi_button_dir)
return -ENODEV;
/* create /proc/acpi/button/lid */
acpi_lid_dir = proc_mkdir(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
if (!acpi_lid_dir) {
ret = -ENODEV;
goto remove_button_dir;
}
/* create /proc/acpi/button/lid/LID/ */
acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device), acpi_lid_dir);
if (!acpi_device_dir(device)) {
ret = -ENODEV;
goto remove_lid_dir;
}
/* create /proc/acpi/button/lid/LID/state */
entry = proc_create_data(ACPI_BUTTON_FILE_STATE,
S_IRUGO, acpi_device_dir(device),
&acpi_button_state_fops, device);
if (!entry) {
ret = -ENODEV;
goto remove_dev_dir;
}
done:
return ret;
remove_dev_dir:
remove_proc_entry(acpi_device_bid(device),
acpi_lid_dir);
acpi_device_dir(device) = NULL;
remove_lid_dir:
remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
acpi_lid_dir = NULL;
remove_button_dir:
remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
acpi_button_dir = NULL;
goto done;
}
static int acpi_button_remove_fs(struct acpi_device *device)
{
struct acpi_button *button = acpi_driver_data(device);
if (button->type != ACPI_BUTTON_TYPE_LID)
return 0;
remove_proc_entry(ACPI_BUTTON_FILE_STATE,
acpi_device_dir(device));
remove_proc_entry(acpi_device_bid(device),
acpi_lid_dir);
acpi_device_dir(device) = NULL;
remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
acpi_lid_dir = NULL;
remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
acpi_button_dir = NULL;
return 0;
}
/* --------------------------------------------------------------------------
Driver Interface
-------------------------------------------------------------------------- */
int acpi_lid_notifier_register(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&acpi_lid_notifier, nb);
}
EXPORT_SYMBOL(acpi_lid_notifier_register);
int acpi_lid_notifier_unregister(struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&acpi_lid_notifier, nb);
}
EXPORT_SYMBOL(acpi_lid_notifier_unregister);
int acpi_lid_open(void)
{
if (!lid_device)
return -ENODEV;
return acpi_lid_evaluate_state(lid_device);
}
EXPORT_SYMBOL(acpi_lid_open);
static int acpi_lid_update_state(struct acpi_device *device)
{
int state;
state = acpi_lid_evaluate_state(device);
if (state < 0)
return state;
return acpi_lid_notify_state(device, state);
}
static void acpi_lid_initialize_state(struct acpi_device *device)
{
switch (lid_init_state) {
case ACPI_BUTTON_LID_INIT_OPEN:
(void)acpi_lid_notify_state(device, 1);
break;
case ACPI_BUTTON_LID_INIT_METHOD:
(void)acpi_lid_update_state(device);
break;
case ACPI_BUTTON_LID_INIT_IGNORE:
default:
break;
}
}
static void acpi_button_notify(struct acpi_device *device, u32 event)
{
struct acpi_button *button = acpi_driver_data(device);
struct input_dev *input;
switch (event) {
case ACPI_FIXED_HARDWARE_EVENT:
event = ACPI_BUTTON_NOTIFY_STATUS;
/* fall through */
case ACPI_BUTTON_NOTIFY_STATUS:
input = button->input;
if (button->type == ACPI_BUTTON_TYPE_LID) {
acpi_lid_update_state(device);
} else {
int keycode;
pm_wakeup_event(&device->dev, 0);
if (button->suspended)
break;
keycode = test_bit(KEY_SLEEP, input->keybit) ?
KEY_SLEEP : KEY_POWER;
input_report_key(input, keycode, 1);
input_sync(input);
input_report_key(input, keycode, 0);
input_sync(input);
acpi_bus_generate_netlink_event(
device->pnp.device_class,
dev_name(&device->dev),
event, ++button->pushed);
}
break;
default:
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Unsupported event [0x%x]\n", event));
break;
}
}
#ifdef CONFIG_PM_SLEEP
static int acpi_button_suspend(struct device *dev)
{
struct acpi_device *device = to_acpi_device(dev);
struct acpi_button *button = acpi_driver_data(device);
button->suspended = true;
return 0;
}
static int acpi_button_resume(struct device *dev)
{
struct acpi_device *device = to_acpi_device(dev);
struct acpi_button *button = acpi_driver_data(device);
button->suspended = false;
if (button->type == ACPI_BUTTON_TYPE_LID)
acpi_lid_initialize_state(device);
return 0;
}
#endif
static int acpi_button_add(struct acpi_device *device)
{
struct acpi_button *button;
struct input_dev *input;
const char *hid = acpi_device_hid(device);
char *name, *class;
int error;
button = kzalloc(sizeof(struct acpi_button), GFP_KERNEL);
if (!button)
return -ENOMEM;
device->driver_data = button;
button->input = input = input_allocate_device();
if (!input) {
error = -ENOMEM;
goto err_free_button;
}
name = acpi_device_name(device);
class = acpi_device_class(device);
if (!strcmp(hid, ACPI_BUTTON_HID_POWER) ||
!strcmp(hid, ACPI_BUTTON_HID_POWERF)) {
button->type = ACPI_BUTTON_TYPE_POWER;
strcpy(name, ACPI_BUTTON_DEVICE_NAME_POWER);
sprintf(class, "%s/%s",
ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_POWER);
} else if (!strcmp(hid, ACPI_BUTTON_HID_SLEEP) ||
!strcmp(hid, ACPI_BUTTON_HID_SLEEPF)) {
button->type = ACPI_BUTTON_TYPE_SLEEP;
strcpy(name, ACPI_BUTTON_DEVICE_NAME_SLEEP);
sprintf(class, "%s/%s",
ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_SLEEP);
} else if (!strcmp(hid, ACPI_BUTTON_HID_LID)) {
button->type = ACPI_BUTTON_TYPE_LID;
strcpy(name, ACPI_BUTTON_DEVICE_NAME_LID);
sprintf(class, "%s/%s",
ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_LID);
button->last_state = !!acpi_lid_evaluate_state(device);
button->last_time = ktime_get();
} else {
printk(KERN_ERR PREFIX "Unsupported hid [%s]\n", hid);
error = -ENODEV;
goto err_free_input;
}
error = acpi_button_add_fs(device);
if (error)
goto err_free_input;
snprintf(button->phys, sizeof(button->phys), "%s/button/input0", hid);
input->name = name;
input->phys = button->phys;
input->id.bustype = BUS_HOST;
input->id.product = button->type;
input->dev.parent = &device->dev;
switch (button->type) {
case ACPI_BUTTON_TYPE_POWER:
input_set_capability(input, EV_KEY, KEY_POWER);
break;
case ACPI_BUTTON_TYPE_SLEEP:
input_set_capability(input, EV_KEY, KEY_SLEEP);
break;
case ACPI_BUTTON_TYPE_LID:
input_set_capability(input, EV_SW, SW_LID);
break;
}
error = input_register_device(input);
if (error)
goto err_remove_fs;
if (button->type == ACPI_BUTTON_TYPE_LID) {
acpi_lid_initialize_state(device);
/*
* This assumes there's only one lid device, or if there are
* more we only care about the last one...
*/
lid_device = device;
}
printk(KERN_INFO PREFIX "%s [%s]\n", name, acpi_device_bid(device));
return 0;
err_remove_fs:
acpi_button_remove_fs(device);
err_free_input:
input_free_device(input);
err_free_button:
kfree(button);
return error;
}
static int acpi_button_remove(struct acpi_device *device)
{
struct acpi_button *button = acpi_driver_data(device);
acpi_button_remove_fs(device);
input_unregister_device(button->input);
kfree(button);
return 0;
}
static int param_set_lid_init_state(const char *val, struct kernel_param *kp)
{
int result = 0;
if (!strncmp(val, "open", sizeof("open") - 1)) {
lid_init_state = ACPI_BUTTON_LID_INIT_OPEN;
pr_info("Notify initial lid state as open\n");
} else if (!strncmp(val, "method", sizeof("method") - 1)) {
lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
pr_info("Notify initial lid state with _LID return value\n");
} else if (!strncmp(val, "ignore", sizeof("ignore") - 1)) {
lid_init_state = ACPI_BUTTON_LID_INIT_IGNORE;
pr_info("Do not notify initial lid state\n");
} else
result = -EINVAL;
return result;
}
static int param_get_lid_init_state(char *buffer, struct kernel_param *kp)
{
switch (lid_init_state) {
case ACPI_BUTTON_LID_INIT_OPEN:
return sprintf(buffer, "open");
case ACPI_BUTTON_LID_INIT_METHOD:
return sprintf(buffer, "method");
case ACPI_BUTTON_LID_INIT_IGNORE:
return sprintf(buffer, "ignore");
default:
return sprintf(buffer, "invalid");
}
return 0;
}
module_param_call(lid_init_state,
param_set_lid_init_state, param_get_lid_init_state,
NULL, 0644);
MODULE_PARM_DESC(lid_init_state, "Behavior for reporting LID initial state");
module_acpi_driver(acpi_button_driver);