diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 26c5b117df22d5011c46c64f2f588f83dd7ed58c..7bd829f247eb5ae98fa3b2c61914d16cf554a941 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -3185,9 +3185,18 @@ static int __init hotkey_init(struct ibm_init_struct *iibm)
 
 		KEY_VENDOR,	/* 0x17: Thinkpad/AccessIBM/Lenovo */
 
+		/* (assignments unknown, please report if found) */
+		KEY_UNKNOWN, KEY_UNKNOWN,
+
+		/*
+		 * The mic mute button only sends 0x1a.  It does not
+		 * automatically mute the mic or change the mute light.
+		 */
+		KEY_MICMUTE,	/* 0x1a: Mic mute (since ?400 or so) */
+
 		/* (assignments unknown, please report if found) */
 		KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN,
-		KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN,
+		KEY_UNKNOWN,
 		},
 	};
 
diff --git a/include/linux/input.h b/include/linux/input.h
index 068784e17972a1ffd907f4365bd5f774e70bcfdf..a637e781433499c8283f2991989ff35a35b7e66c 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -438,6 +438,8 @@ struct input_keymap_entry {
 #define KEY_WIMAX		246
 #define KEY_RFKILL		247	/* Key that controls all radios */
 
+#define KEY_MICMUTE		248	/* Mute / unmute the microphone */
+
 /* Code 255 is reserved for special needs of AT keyboard driver */
 
 #define BTN_MISC		0x100