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Commit 2f0d2604 authored by Andrey Moiseev's avatar Andrey Moiseev Committed by Dmitry Torokhov
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Input: i8042 - i8042_flush fix for a full 8042 buffer 



When 8042 internal data buffer is full, the driver
erroneously decides that the controller is not present.

i8042_flush returns the number of flushed bytes, which is
in 0 - I8042_BUFFER_SIZE range inclusive. Therefore, i8042_flush
has no way to indicate an error. Moreover i8042_controller_check
takes initially full buffer (i8042_flush returned
I8042_BUFFER_SIZE) as a sign of absence of the controller.

Let's change i8042 to return success/error instead and make sure
we do not return error prematurely.

Signed-off-by: default avatarAndrey Moiseev <o2g.org.ru@gmail.com>
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent 049d75f7

drivers/input/serio/i8042.c

+14 −9
Original line number Original line Diff line number Diff line
@@ -223,21 +223,26 @@ static int i8042_flush(void) 
{

{

	unsigned long flags;

	unsigned long flags;

	unsigned char data, str;

	unsigned char data, str;

	int i = 0;

	int count = 0;

	int retval = 0;





	spin_lock_irqsave(&i8042_lock, flags);

	spin_lock_irqsave(&i8042_lock, flags);





	while (((str = i8042_read_status()) & I8042_STR_OBF) && (i < I8042_BUFFER_SIZE)) {

	while ((str = i8042_read_status()) & I8042_STR_OBF) {

		if (count++ < I8042_BUFFER_SIZE) {

			udelay(50);

			udelay(50);

			data = i8042_read_data();

			data = i8042_read_data();

		i++;

			dbg("%02x <- i8042 (flush, %s)\n",

			dbg("%02x <- i8042 (flush, %s)\n",

			    data, str & I8042_STR_AUXDATA ? "aux" : "kbd");

			    data, str & I8042_STR_AUXDATA ? "aux" : "kbd");

		} else {

			retval = -EIO;

			break;

		}

	}

	}





	spin_unlock_irqrestore(&i8042_lock, flags);

	spin_unlock_irqrestore(&i8042_lock, flags);





	return i;

	return retval;

}

}





/*

/*
@@ -849,7 +854,7 @@ static int __init i8042_check_aux(void) 




static int i8042_controller_check(void)

static int i8042_controller_check(void)

{

{

	if (i8042_flush() == I8042_BUFFER_SIZE) {

	if (i8042_flush()) {

		pr_err("No controller found\n");

		pr_err("No controller found\n");

		return -ENODEV;

		return -ENODEV;

	}

	}