diff --git a/chip/lm4/keyboard_scan.c b/chip/lm4/keyboard_scan.c
index bb92ad2689..2faa2a88f6 100644
--- a/chip/lm4/keyboard_scan.c
+++ b/chip/lm4/keyboard_scan.c
@@ -63,6 +63,8 @@ enum COLUMN_INDEX {
 
 #define KB_COLS 13
 
+
+static int enable_scanning = 1;
 static uint8_t raw_state[KB_COLS];
 static uint8_t raw_state_at_boot[KB_COLS];
 static int recovery_key_pressed;
@@ -95,6 +97,8 @@ static const uint8_t actual_key_masks[4][KB_COLS] = {
 static void select_column(int col)
 {
 	if (col == COLUMN_ASSERT_ALL) {
+		if (!enable_scanning)
+			return;
 		LM4_GPIO_DIR(LM4_GPIO_P) = 0xff;
 		LM4_GPIO_DIR(LM4_GPIO_Q) |= 0x1f;
 		LM4_GPIO_DATA(LM4_GPIO_P, 0xff) = 0;
@@ -102,7 +106,11 @@ static void select_column(int col)
 	} else {
 		LM4_GPIO_DIR(LM4_GPIO_P) = 0;
 		LM4_GPIO_DIR(LM4_GPIO_Q) &= ~0x1f;
-		if (col < 8) {
+		/* Return after the above TRI_STATE_ALL has be run. */
+		if (!enable_scanning)
+			return;
+
+		if (col >= 0 && col < 8) {
 			LM4_GPIO_DIR(LM4_GPIO_P) |= 1 << col;
 			LM4_GPIO_DATA(LM4_GPIO_P, 1 << col) = 0;
 		} else if (col != COLUMN_TRI_STATE_ALL) {
@@ -232,7 +240,7 @@ static int check_keys_changed(void)
 			for (i = 0; i < 8; ++i) {
 				uint8_t prev = (raw_state[c] >> i) & 1;
 				uint8_t now = (r >> i) & 1;
-				if (prev != now) {
+				if (prev != now && enable_scanning) {
 					keyboard_state_changed(i, c, now);
 				}
 			}
@@ -360,6 +368,7 @@ void keyboard_scan_task(void)
 
 	/* Enable interrupts */
 	task_enable_irq(KB_SCAN_ROW_IRQ);
+	enable_scanning = 1;
 
 	while (1) {
 		wait_for_interrupt();
@@ -367,7 +376,7 @@ void keyboard_scan_task(void)
 
 		enter_polling_mode();
 		/* Busy polling keyboard state. */
-		while (1) {
+		while (enable_scanning) {
 			/* sleep for debounce. */
 			usleep(SCAN_LOOP_DELAY);
 			/* Check for keys down */
@@ -381,10 +390,10 @@ void keyboard_scan_task(void)
 				}
 			}
 		}
-		/* TODO: (crosbug.com/p/7484) A race condition here.
-		 *       If a key state is changed here (before interrupt is
-		 *       enabled), it will be lost.
-		 */
+		/* Don't continue if the power button is not released yet. */
+		while (!enable_scanning) {
+			usleep(SCAN_LOOP_DELAY);
+		}
 	}
 }
 
@@ -441,3 +450,21 @@ int keyboard_get_scan(uint8_t **buffp, int max_bytes)
 {
 	return -1;
 }
+
+
+/* The actuall implementation is controlling the enable_scanning variable,
+ * then that controls whether select_column() can pull-down columns or not.
+ */
+void keyboard_enable_scanning(int enable)
+{
+	enable_scanning = enable;
+	if (enable) {
+		/* A power button press had tri-stated all columns (see the
+		 * 'else' statement below), we need a wake-up to unlock
+		 * the task_wait_event() loop after wait_for_interrupt(). */
+		task_wake(TASK_ID_KEYSCAN);
+	} else {
+		select_column(COLUMN_TRI_STATE_ALL);
+		keyboard_clear_underlying_buffer();
+	}
+}
diff --git a/chip/lm4/power_button.c b/chip/lm4/power_button.c
index 66505d3e59..66fc7b7589 100644
--- a/chip/lm4/power_button.c
+++ b/chip/lm4/power_button.c
@@ -200,6 +200,7 @@ static void power_button_released(uint64_t tnow)
 	tnext_state = tnow;
 	*memmap_switches &= ~EC_SWITCH_POWER_BUTTON_PRESSED;
 	keyboard_set_power_button(0);
+	keyboard_enable_scanning(1);
 }
 
 
@@ -528,6 +529,12 @@ void power_button_interrupt(enum gpio_signal signal)
 	case GPIO_POWER_BUTTONn:
 		/* Reset power button debounce time */
 		tdebounce_pwr = get_time().val + PWRBTN_DEBOUNCE_US;
+		if (get_power_button_pressed()) {
+			/* We want to disable the matrix scan as soon as
+			 * possible to reduce the risk of false-reboot triggered
+			 * by those keys on the same column with ESC key. */
+			keyboard_enable_scanning(0);
+		}
 		break;
 	case GPIO_PCH_BKLTEN:
 		update_backlight();
diff --git a/common/i8042.c b/common/i8042.c
index 35e1f2b094..54eb668f3c 100644
--- a/common/i8042.c
+++ b/common/i8042.c
@@ -46,7 +46,7 @@ static int i8042_irq_enabled = 0;
 
 
 /* Reset all i8042 buffer */
-void i8042_init()
+void i8042_flush_buffer()
 {
 	head_to_buffer = tail_to_buffer = 0;
 	keyboard_clear_buffer();
diff --git a/common/keyboard.c b/common/keyboard.c
index 2d69dba438..6b2dc48088 100644
--- a/common/keyboard.c
+++ b/common/keyboard.c
@@ -255,9 +255,9 @@ static void reset_rate_and_delay(void)
 }
 
 
-static void clear_underlying_buffer(void)
+void keyboard_clear_underlying_buffer(void)
 {
-	i8042_init();
+	i8042_flush_buffer();
 }
 
 
@@ -482,25 +482,25 @@ int handle_keyboard_data(uint8_t data, uint8_t *output)
 		case I8042_CMD_ENABLE:
 			output[out_len++] = I8042_RET_ACK;
 			keyboard_enable(1);
-			clear_underlying_buffer();
+			keyboard_clear_underlying_buffer();
 			break;
 
 		case I8042_CMD_RESET_DIS:
 			output[out_len++] = I8042_RET_ACK;
 			keyboard_enable(0);
 			reset_rate_and_delay();
-			clear_underlying_buffer();
+			keyboard_clear_underlying_buffer();
 			break;
 
 		case I8042_CMD_RESET_DEF:
 			output[out_len++] = I8042_RET_ACK;
 			reset_rate_and_delay();
-			clear_underlying_buffer();
+			keyboard_clear_underlying_buffer();
 			break;
 
 		case I8042_CMD_RESET_BAT:
 			reset_rate_and_delay();
-			clear_underlying_buffer();
+			keyboard_clear_underlying_buffer();
 			output[out_len++] = I8042_RET_ACK;
 			output[out_len++] = I8042_RET_BAT;
 			output[out_len++] = I8042_RET_BAT;
@@ -613,7 +613,7 @@ int handle_keyboard_command(uint8_t command, uint8_t *output)
 		} else {
 			CPRINTF("[Unsupported cmd: 0x%02x]\n", command);
 			reset_rate_and_delay();
-			clear_underlying_buffer();
+			keyboard_clear_underlying_buffer();
 			output[out_len++] = I8042_RET_NAK;
 			data_port_state = STATE_NORMAL;
 		}
diff --git a/include/i8042.h b/include/i8042.h
index c3d858bee1..d88e3acb1f 100644
--- a/include/i8042.h
+++ b/include/i8042.h
@@ -90,7 +90,7 @@
 #define I8042_ENIRQ1            (1 << 0)
 
 
-void i8042_init(void);
+void i8042_flush_buffer(void);
 
 
 /* common/i8042.c implements this function, which is called by lpc.c
diff --git a/include/keyboard.h b/include/keyboard.h
index 78884c1053..775135f1b7 100644
--- a/include/keyboard.h
+++ b/include/keyboard.h
@@ -53,6 +53,9 @@ void kblog_put(char type, uint8_t byte);
 #define MAX_KEYBOARD_MATRIX_ROWS 8
 #define MAX_KEYBOARD_MATRIX_COLS 16
 
+/* Clear the keyboard buffer to host. */
+void keyboard_clear_underlying_buffer(void);
+
 /* Asks the underlayer EC lib what keys are pressed right now.
  *
  * Sets bit_array to a debounced array of which keys are currently pressed,
diff --git a/include/keyboard_scan.h b/include/keyboard_scan.h
index 684885c82a..67e09e0312 100644
--- a/include/keyboard_scan.h
+++ b/include/keyboard_scan.h
@@ -19,4 +19,9 @@ int keyboard_scan_recovery_pressed(void);
 /* clear any saved keyboard state (empty FIFO, etc) */
 void keyboard_clear_state(void);
 
+
+/* Enables/disables keyboard matrix scan. */
+void keyboard_enable_scanning(int enable);
+
+
 #endif  /* __CROS_KEYBOARD_SCAN_H */