Input: libps2 - handle 0xfc responses from devices

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/serio/libps2.c

@@ -262,9 +262,17 @@ int ps2_handle_ack(struct ps2dev *ps2dev, unsigned char data)
 			break;
 
 		case PS2_RET_NAK:
-			ps2dev->nak = 1;
+			ps2dev->flags |= PS2_FLAG_NAK;
+			ps2dev->nak = PS2_RET_NAK;
 			break;
 
+		case PS2_RET_ERR:
+			if (ps2dev->flags & PS2_FLAG_NAK) {
+				ps2dev->flags &= ~PS2_FLAG_NAK;
+				ps2dev->nak = PS2_RET_ERR;
+				break;
+			}
+
 		/*
 		 * Workaround for mice which don't ACK the Get ID command.
 		 * These are valid mouse IDs that we recognize.
@@ -282,8 +290,11 @@ int ps2_handle_ack(struct ps2dev *ps2dev, unsigned char data)
 	}
 
 
-	if (!ps2dev->nak && ps2dev->cmdcnt)
-		ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
+	if (!ps2dev->nak) {
+		ps2dev->flags &= ~PS2_FLAG_NAK;
+		if (ps2dev->cmdcnt)
+			ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
+	}
 
 	ps2dev->flags &= ~PS2_FLAG_ACK;
 	wake_up(&ps2dev->wait);
@@ -329,6 +340,7 @@ void ps2_cmd_aborted(struct ps2dev *ps2dev)
 	if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
 		wake_up(&ps2dev->wait);
 
-	ps2dev->flags = 0;
+	/* reset all flags except last nack */
+	ps2dev->flags &= PS2_FLAG_NAK;
 }
 EXPORT_SYMBOL(ps2_cmd_aborted);

include/linux/libps2.h

@@ -18,11 +18,13 @@
 #define PS2_RET_ID		0x00
 #define PS2_RET_ACK		0xfa
 #define PS2_RET_NAK		0xfe
+#define PS2_RET_ERR		0xfc
 
 #define PS2_FLAG_ACK		1	/* Waiting for ACK/NAK */
 #define PS2_FLAG_CMD		2	/* Waiting for command to finish */
 #define PS2_FLAG_CMD1		4	/* Waiting for the first byte of command response */
 #define PS2_FLAG_WAITID		8	/* Command execiting is GET ID */
+#define PS2_FLAG_NAK		16	/* Last transmission was NAKed */
 
 struct ps2dev {
 	struct serio *serio;