input: Expect only one character in interrupt in i8042.c, this eases

       the load on the controller (only one status read per interrupt). Also
       do polling only some time after an interrupt happened.

drivers/input/serio/i8042.c

@@ -371,65 +371,60 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 	unsigned long flags;
 	unsigned char str, data;
 	unsigned int dfl;
-	struct {
-		int data;
-		int str;
-	} buffer[I8042_BUFFER_SIZE];
-	int i, j = 0;
 
 	spin_lock_irqsave(&i8042_lock, flags);
-
-	while (j < I8042_BUFFER_SIZE && 
-	    (buffer[j].str = i8042_read_status()) & I8042_STR_OBF)
-		buffer[j++].data = i8042_read_data();
-
+	str = i8042_read_status();
+	data = i8042_read_data();
 	spin_unlock_irqrestore(&i8042_lock, flags);
 
-	for (i = 0; i < j; i++) {
-
-		str = buffer[i].str;
-		data = buffer[i].data;
-
-		dfl = ((str & I8042_STR_PARITY) ? SERIO_PARITY : 0) |
-		      ((str & I8042_STR_TIMEOUT) ? SERIO_TIMEOUT : 0);
-
-		if (i8042_mux_values[0].exists && (str & I8042_STR_AUXDATA)) {
+	if (~str & I8042_STR_OBF) {
+		if (irq) dbg("Interrupt %d, without any data", irq);
+		return IRQ_RETVAL(0);
+	}
 
-			if (str & I8042_STR_MUXERR) {
-				switch (data) {
-					case 0xfd:
-					case 0xfe: dfl = SERIO_TIMEOUT; break;
-					case 0xff: dfl = SERIO_PARITY; break;
-				}
-				data = 0xfe;
-			} else dfl = 0;
+	dfl = ((str & I8042_STR_PARITY) ? SERIO_PARITY : 0) |
+	      ((str & I8042_STR_TIMEOUT) ? SERIO_TIMEOUT : 0);
 
-			dbg("%02x <- i8042 (interrupt, aux%d, %d%s%s)",
-				data, (str >> 6), irq, 
-				dfl & SERIO_PARITY ? ", bad parity" : "",
-				dfl & SERIO_TIMEOUT ? ", timeout" : "");
+	if (i8042_mux_values[0].exists && (str & I8042_STR_AUXDATA)) {
 
-			serio_interrupt(i8042_mux_port + ((str >> 6) & 3), data, dfl, regs);
-			continue;
-		}
+		if (str & I8042_STR_MUXERR) {
+			switch (data) {
+				case 0xfd:
+				case 0xfe: dfl = SERIO_TIMEOUT; break;
+				case 0xff: dfl = SERIO_PARITY; break;
+			}
+			data = 0xfe;
+		} else dfl = 0;
 
-		dbg("%02x <- i8042 (interrupt, %s, %d%s%s)",
-			data, (str & I8042_STR_AUXDATA) ? "aux" : "kbd", irq, 
+		dbg("%02x <- i8042 (interrupt, aux%d, %d%s%s)",
+			data, (str >> 6), irq, 
 			dfl & SERIO_PARITY ? ", bad parity" : "",
 			dfl & SERIO_TIMEOUT ? ", timeout" : "");
 
-		if (i8042_aux_values.exists && (str & I8042_STR_AUXDATA)) {
-			serio_interrupt(&i8042_aux_port, data, dfl, regs);
-			continue;
-		}
+		serio_interrupt(i8042_mux_port + ((str >> 6) & 3), data, dfl, regs);
+		
+		goto irq_ret;
+	}
 
-		if (!i8042_kbd_values.exists)
-			continue;
+	dbg("%02x <- i8042 (interrupt, %s, %d%s%s)",
+		data, (str & I8042_STR_AUXDATA) ? "aux" : "kbd", irq, 
+		dfl & SERIO_PARITY ? ", bad parity" : "",
+		dfl & SERIO_TIMEOUT ? ", timeout" : "");
 
-		serio_interrupt(&i8042_kbd_port, data, dfl, regs);
+	if (i8042_aux_values.exists && (str & I8042_STR_AUXDATA)) {
+		serio_interrupt(&i8042_aux_port, data, dfl, regs);
+		goto irq_ret;
 	}
 
-	return IRQ_RETVAL(j);
+	if (!i8042_kbd_values.exists)
+		goto irq_ret;
+
+	serio_interrupt(&i8042_kbd_port, data, dfl, regs);
+
+irq_ret:
+
+	mod_timer(&i8042_timer, jiffies + I8042_POLL_PERIOD);
+	return IRQ_RETVAL(1);
 }
 
 /*
@@ -645,7 +640,6 @@ static int __init i8042_port_register(struct i8042_values *values, struct serio
 static void i8042_timer_func(unsigned long data)
 {
 	i8042_interrupt(0, NULL, NULL);
-	mod_timer(&i8042_timer, jiffies + I8042_POLL_PERIOD);
 }
 
 
@@ -899,6 +893,9 @@ int __init i8042_init(void)
 
 	dbg_init();
 
+	init_timer(&i8042_timer);
+	i8042_timer.function = i8042_timer_func;
+
 	if (i8042_platform_init())
 		return -EBUSY;
 
@@ -923,8 +920,6 @@ int __init i8042_init(void)
 
 	i8042_port_register(&i8042_kbd_values, &i8042_kbd_port);
 
-	init_timer(&i8042_timer);
-	i8042_timer.function = i8042_timer_func;
 	mod_timer(&i8042_timer, jiffies + I8042_POLL_PERIOD);
 
         if (sysdev_class_register(&kbc_sysclass) == 0) {