[powerkey] Ignore bursts of power key presses. Fixes JB#37181

In some individual devices pressing power key button can cause a bursts
of power key press and release events to be emitted - so that pressing
power key just once invokes actions bound to double presses. Wear and
tear can make the problem more likely to occur also in devices that
initially function just fine.

Assume power key presses that happen less than 50 milliseconds after
the previous power key release are caused by hw faults and ignore them.

Signed-off-by: Simo Piiroinen <simo.piiroinen@jollamobile.com>

powerkey.c

@@ -2869,6 +2869,19 @@ pwrkey_datapipe_ngfd_available_cb(gconstpointer data)
 static void
 pwrkey_datapipes_keypress_cb(gconstpointer const data)
 {
+    /* Faulty/aged physical power key buttons can generate
+     * bursts of press and release events that are then
+     * interpreted as double presses. To avoid this we
+     * ignore power key presses that occur so soon after
+     * previous release that they are unlikely to be
+     * caused by human activity. */
+
+    /* Minimum delay between power key release and press. */
+    static const int64_t press_delay = 50;
+
+    /* Time limit for accepting the next power key press */
+    static int64_t press_limit = 0;
+
     const struct input_event * const *evp;
     const struct input_event *ev;
 
@@ -2883,21 +2896,33 @@ pwrkey_datapipes_keypress_cb(gconstpointer const data)
         switch( ev->code ) {
         case KEY_POWER:
             if( ev->value == 1 ) {
-                mce_log(LL_CRUCIAL, "powerkey pressed");
-                /* Detect repeated power key pressing while
-                 * proximity sensor is covered; assume it means
-                 * the sensor is stuck and user wants to be able
-                 * to turn on the display regardless of the sensor
-                 * state */
-                pwrkey_ps_override_evaluate();
-
-                /* Power key pressed */
-                pwrkey_stm_powerkey_pressed();
+                if( mce_lib_get_boot_tick() < press_limit ) {
+                    /* Too soon after the previous powerkey
+                     * release -> assume faulty hw sending
+                     * bursts of presses */
+                    mce_log(LL_CRUCIAL, "powerkey press ignored");
+                }
+                else {
+                    mce_log(LL_CRUCIAL, "powerkey pressed");
+                    /* Detect repeated power key pressing while
+                     * proximity sensor is covered; assume it means
+                     * the sensor is stuck and user wants to be able
+                     * to turn on the display regardless of the sensor
+                     * state */
+                    pwrkey_ps_override_evaluate();
+
+                    /* Power key pressed */
+                    pwrkey_stm_powerkey_pressed();
+                }
             }
             else if( ev->value == 0 ) {
                 mce_log(LL_CRUCIAL, "powerkey released");
                 /* Power key released */
                 pwrkey_stm_powerkey_released();
+
+                /* Adjust time limit for accepting the next power
+                 * key press */
+                press_limit = mce_lib_get_boot_tick() + press_delay;
             }
 
             pwrkey_stm_rethink_wakelock();