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Input: i8042 - i8042_flush fix for a full 8042 buffer

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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: Andrey Moiseev <o2g.org.ru@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Andrey Moiseev 2013-09-16 15:17:31 -07:00 committed by Dmitry Torokhov
parent 049d75f72d
commit 2f0d260413
1 changed files with 14 additions and 9 deletions
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23
drivers/input/serio/i8042.c
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@ -223,21 +223,26 @@ static int i8042_flush(void)
{
unsigned long flags;
unsigned char data, str;
int i = 0;
int count = 0;
int retval = 0;
spin_lock_irqsave(&i8042_lock, flags);
while (((str = i8042_read_status()) & I8042_STR_OBF) && (i < I8042_BUFFER_SIZE)) {
udelay(50);
data = i8042_read_data();
i++;
dbg("%02x <- i8042 (flush, %s)\n",
data, str & I8042_STR_AUXDATA ? "aux" : "kbd");
while ((str = i8042_read_status()) & I8042_STR_OBF) {
if (count++ < I8042_BUFFER_SIZE) {
udelay(50);
data = i8042_read_data();
dbg("%02x <- i8042 (flush, %s)\n",
data, str & I8042_STR_AUXDATA ? "aux" : "kbd");
} else {
retval = -EIO;
break;
}
}
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)
{
if (i8042_flush() == I8042_BUFFER_SIZE) {
if (i8042_flush()) {
pr_err("No controller found\n");
return -ENODEV;
}