---

yaml
---
r: 40709
b: refs/heads/master
c: a216a4b
h: refs/heads/master
i:
  40707: 876b983
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 6c595fb12fa6c1fe382cc086fdade4acd93c643f
+refs/heads/master: a216a4b6e6f1fdfd3d1f20f03d9d45f05a63d643

trunk/drivers/input/serio/i8042.c

@@ -322,23 +322,27 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id)
 		dfl = 0;
 		if (str & I8042_STR_MUXERR) {
 			dbg("MUX error, status is %02x, data is %02x", str, data);
-			switch (data) {
-				default:
 /*
  * When MUXERR condition is signalled the data register can only contain
  * 0xfd, 0xfe or 0xff if implementation follows the spec. Unfortunately
- * it is not always the case. Some KBC just get confused which port the
- * data came from and signal error leaving the data intact. They _do not_
- * revert to legacy mode (actually I've never seen KBC reverting to legacy
- * mode yet, when we see one we'll add proper handling).
- * Anyway, we will assume that the data came from the same serio last byte
+ * it is not always the case. Some KBCs also report 0xfc when there is
+ * nothing connected to the port while others sometimes get confused which
+ * port the data came from and signal error leaving the data intact. They
+ * _do not_ revert to legacy mode (actually I've never seen KBC reverting
+ * to legacy mode yet, when we see one we'll add proper handling).
+ * Anyway, we process 0xfc, 0xfd, 0xfe and 0xff as timeouts, and for the
+ * rest assume that the data came from the same serio last byte
  * was transmitted (if transmission happened not too long ago).
  */
+
+			switch (data) {
+				default:
 					if (time_before(jiffies, last_transmit + HZ/10)) {
 						str = last_str;
 						break;
 					}
 					/* fall through - report timeout */
+				case 0xfc:
 				case 0xfd:
 				case 0xfe: dfl = SERIO_TIMEOUT; data = 0xfe; break;
 				case 0xff: dfl = SERIO_PARITY;  data = 0xfe; break;