[PATCH 5.4 110/214] ACPI: button: fix handling lid state changes when input device closed

From: Greg Kroah-Hartman
Date: Tue Nov 03 2020 - 16:33:32 EST


From: dmitry.torokhov@xxxxxxxxx <dmitry.torokhov@xxxxxxxxx>

commit 21988a8e51479ceffe7b0568b170effabb708dfe upstream.

The original intent of 84d3f6b76447 was to delay evaluating lid state until
all drivers have been loaded, with input device being opened from userspace
serving as a signal for this condition. Let's ensure that state updates
happen even if userspace closed (or in the future inhibited) input device.

Note that if we go through suspend/resume cycle we assume the system has
been fully initialized even if LID input device has not been opened yet.

This has a side-effect of fixing access to input->users outside of
input->mutex protections by the way of eliminating said accesses and using
driver private flag.

Fixes: 84d3f6b76447 ("ACPI / button: Delay acpi_lid_initialize_state() until first user space open")
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Cc: 4.15+ <stable@xxxxxxxxxxxxxxx> # 4.15+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/acpi/button.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

--- a/drivers/acpi/button.c
+++ b/drivers/acpi/button.c
@@ -136,6 +136,7 @@ struct acpi_button {
int last_state;
ktime_t last_time;
bool suspended;
+ bool lid_state_initialized;
};

static BLOCKING_NOTIFIER_HEAD(acpi_lid_notifier);
@@ -391,6 +392,8 @@ static int acpi_lid_update_state(struct

static void acpi_lid_initialize_state(struct acpi_device *device)
{
+ struct acpi_button *button = acpi_driver_data(device);
+
switch (lid_init_state) {
case ACPI_BUTTON_LID_INIT_OPEN:
(void)acpi_lid_notify_state(device, 1);
@@ -402,13 +405,14 @@ static void acpi_lid_initialize_state(st
default:
break;
}
+
+ button->lid_state_initialized = true;
}

static void acpi_button_notify(struct acpi_device *device, u32 event)
{
struct acpi_button *button = acpi_driver_data(device);
struct input_dev *input;
- int users;

switch (event) {
case ACPI_FIXED_HARDWARE_EVENT:
@@ -417,10 +421,7 @@ static void acpi_button_notify(struct ac
case ACPI_BUTTON_NOTIFY_STATUS:
input = button->input;
if (button->type == ACPI_BUTTON_TYPE_LID) {
- mutex_lock(&button->input->mutex);
- users = button->input->users;
- mutex_unlock(&button->input->mutex);
- if (users)
+ if (button->lid_state_initialized)
acpi_lid_update_state(device, true);
} else {
int keycode;
@@ -465,7 +466,7 @@ static int acpi_button_resume(struct dev
struct acpi_button *button = acpi_driver_data(device);

button->suspended = false;
- if (button->type == ACPI_BUTTON_TYPE_LID && button->input->users) {
+ if (button->type == ACPI_BUTTON_TYPE_LID) {
button->last_state = !!acpi_lid_evaluate_state(device);
button->last_time = ktime_get();
acpi_lid_initialize_state(device);