[PATCH] atkbd: 0xfa is ACK

The 0xfa code can be a key scancode or it can be a protocol scancode.

Only few keyboards use it as a key scancode, and if we always interpret
it as a protocol scancode then these rare keyboards will have a dead
key.  If we interpret it as a key scancode then we have a dead keyboard
in case it was protocol.

Clearly it is safer to prefer to interpret it as a protocol scancode.

This moves the test for ACK and NAK up, so that they are always seen as
protocol.

This is just a minimal patch.  What I did in 1.1.54 was to keep track of
commands sent with a flag reply_expected, so that 0xfa could be taken as
ACK when a reply is expected and as key scancode otherwise.  That is the
better solution, but requires larger surgery.

drivers/input/keyboard/atkbd.c

@@ -184,11 +184,19 @@ static irqreturn_t atkbd_interrupt(struct serio *serio, unsigned char data,
 		atkbd->resend = 0;
 #endif
 
+	switch (code) {
+		case ATKBD_RET_ACK:
+			atkbd->ack = 1;
+			goto out;
+		case ATKBD_RET_NAK:
+			atkbd->ack = -1;
+			goto out;
+	}
+
 	if (atkbd->translated) do {
 
 		if (atkbd->emul != 1) {
-			if (code == ATKBD_RET_EMUL0 || code == ATKBD_RET_EMUL1 ||
-			    code == ATKBD_RET_ACK || code == ATKBD_RET_NAK)
+			if (code == ATKBD_RET_EMUL0 || code == ATKBD_RET_EMUL1)
 				break;
 			if (code == ATKBD_RET_BAT) {
 				if (!atkbd->bat_xl)
@@ -212,15 +220,6 @@ static irqreturn_t atkbd_interrupt(struct serio *serio, unsigned char data,
 
 	} while (0);
 
-	switch (code) {
-		case ATKBD_RET_ACK:
-			atkbd->ack = 1;
-			goto out;
-		case ATKBD_RET_NAK:
-			atkbd->ack = -1;
-			goto out;
-	}
-
 	if (atkbd->cmdcnt) {
 		atkbd->cmdbuf[--atkbd->cmdcnt] = code;
 		goto out;