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.
The fix:
i8042_flush should perform one more status check after
I8042_BUFFER_SIZE bytes have been read, and, if it succeeds,
indicate the error by returning -1. i8042_controller_check
should be changed appropriately.
Signed-off-by: Andrey Moiseev <o2g.org...@gmail.com>
---
diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index 78e4de4..cdda786 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -222,29 +222,32 @@ static int i8042_wait_write(void)
static int i8042_flush(void)
{
unsigned long flags;
unsigned char data, str;
int i = 0;
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) && (i <=
I8042_BUFFER_SIZE)) {
udelay(50);
data = i8042_read_data();
i++;
dbg("%02x <- i8042 (flush, %s)\n",
data, str & I8042_STR_AUXDATA ? "aux" : "kbd");
}
spin_unlock_irqrestore(&i8042_lock, flags);
+ if (i == I8042_BUFFER_SIZE + 1)
+ return -1;
+
return i;
}
/*
* i8042_command() executes a command on the i8042. It also sends the input
* parameter(s) of the commands to it, and receives the output value(s). The
* parameters are to be stored in the param array, and the output is placed
* into the same array. The number of the parameters and output values is
* encoded in bits 8-11 of the command number.
*/
@@ -849,11 +852,11 @@ static int __init i8042_check_aux(void)
static int i8042_controller_check(void)
{
- if (i8042_flush() == I8042_BUFFER_SIZE) {
+ if (i8042_flush() == -1) {
pr_err("No controller found\n");
return -ENODEV;
}
return 0;
}
--
1.8.4
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