ACPI: thinkpad-acpi: add mutex-based locking to input device event send path

Protect the input device event sending path with a mutex, since hot key
input events are not atomic and require an cohesive event block to be sent
together.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/misc/thinkpad_acpi.c b/drivers/misc/thinkpad_acpi.c
index 8aa0f9694b87..0ced9d65c6be 100644
--- a/drivers/misc/thinkpad_acpi.c
+++ b/drivers/misc/thinkpad_acpi.c
@@ -519,6 +519,7 @@ static char *next_cmd(char **cmds)
 static struct platform_device *tpacpi_pdev;
 static struct class_device *tpacpi_hwmon;
 static struct input_dev *tpacpi_inputdev;
+static struct mutex tpacpi_inputdev_send_mutex;
 
 
 static int tpacpi_resume_handler(struct platform_device *pdev)
@@ -1131,6 +1132,8 @@ static void tpacpi_input_send_key(unsigned int scancode,
                                   unsigned int keycode)
 {
         if (keycode != KEY_RESERVED) {
+                mutex_lock(&tpacpi_inputdev_send_mutex);
+
                 input_report_key(tpacpi_inputdev, keycode, 1);
                 if (keycode == KEY_UNKNOWN)
                         input_event(tpacpi_inputdev, EV_MSC, MSC_SCAN,
@@ -1142,6 +1145,8 @@ static void tpacpi_input_send_key(unsigned int scancode,
                         input_event(tpacpi_inputdev, EV_MSC, MSC_SCAN,
                                     scancode);
                 input_sync(tpacpi_inputdev);
+
+                mutex_unlock(&tpacpi_inputdev_send_mutex);
         }
 }
 
@@ -1149,11 +1154,15 @@ static void tpacpi_input_send_radiosw(void)
 {
         int wlsw;
 
+        mutex_lock(&tpacpi_inputdev_send_mutex);
+
         if (tp_features.hotkey_wlsw && !hotkey_get_wlsw(&wlsw)) {
                 input_report_switch(tpacpi_inputdev,
                                     SW_RADIO, !!wlsw);
                 input_sync(tpacpi_inputdev);
         }
+
+        mutex_unlock(&tpacpi_inputdev_send_mutex);
 }
 
 static void hotkey_notify(struct ibm_struct *ibm, u32 event)
@@ -4737,6 +4746,7 @@ static int __init thinkpad_acpi_module_init(void)
                 thinkpad_acpi_module_exit();
                 return ret;
         }
+        mutex_init(&tpacpi_inputdev_send_mutex);
         tpacpi_inputdev = input_allocate_device();
         if (!tpacpi_inputdev) {
                 printk(IBM_ERR "unable to allocate input device\n");