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Commit 147b903d authored by Dmitry Torokhov's avatar Dmitry Torokhov
Browse files

Input: libps2 - add debugging statements 



Debugging via i8042.debug and analyzing raw PS/2 data stream may be
cumbersome as you need to locate the boundaries of commands, decipher the
sliced commands, etc, etc. Let's add a bit more high level debug statements
for ps2_sendbyte(), ps2_command(), and ps2_sliced_command().

We do not introduce a new module parameter, but rater rely on the kernel
having dynamic debug facility enabled (which most everyone has nowadays).
Enable with:

echo "file libps2.c +pf" > /sys/kernel/debug/dynamic_debug/control

or add "libps2.dyndbg=+pf" to the kernel command line.

Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent 08be954b

drivers/input/serio/libps2.c

+39 −13
Original line number Diff line number Diff line
@@ -26,22 +26,20 @@ MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>"); 
MODULE_DESCRIPTION("PS/2 driver library");

MODULE_LICENSE("GPL");



/*

 * ps2_sendbyte() sends a byte to the device and waits for acknowledge.

 * It doesn't handle retransmission, though it could - because if there

 * is a need for retransmissions device has to be replaced anyway.

 *

 * ps2_sendbyte() can only be called from a process context.

 */



int ps2_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout)

static int ps2_do_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout)

{

	int error;



	serio_pause_rx(ps2dev->serio);

	ps2dev->nak = 1;

	ps2dev->flags |= PS2_FLAG_ACK;

	serio_continue_rx(ps2dev->serio);



	if (serio_write(ps2dev->serio, byte) == 0)

	error = serio_write(ps2dev->serio, byte);

	if (error)

		dev_dbg(&ps2dev->serio->dev,

			"failed to write %#02x: %d\n", byte, error);

	else

		wait_event_timeout(ps2dev->wait,

				   !(ps2dev->flags & PS2_FLAG_ACK),

				   msecs_to_jiffies(timeout));
@@ -52,6 +50,24 @@ int ps2_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout) 


	return -ps2dev->nak;

}



/*

 * ps2_sendbyte() sends a byte to the device and waits for acknowledge.

 * It doesn't handle retransmission, though it could - because if there

 * is a need for retransmissions device has to be replaced anyway.

 *

 * ps2_sendbyte() can only be called from a process context.

 */



int ps2_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout)

{

	int retval;



	retval = ps2_do_sendbyte(ps2dev, byte, timeout);

	dev_dbg(&ps2dev->serio->dev, "%02x - %x\n", byte, ps2dev->nak);



	return retval;

}

EXPORT_SYMBOL(ps2_sendbyte);



void ps2_begin_command(struct ps2dev *ps2dev)
@@ -186,6 +202,7 @@ int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command) 
	unsigned int receive = (command >> 8) & 0xf;

	int rc = -1;

	int i;

	u8 send_param[16];



	if (receive > sizeof(ps2dev->cmdbuf)) {

		WARN_ON(1);
@@ -197,6 +214,8 @@ int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command) 
		return -1;

	}



	memcpy(send_param, param, send);



	serio_pause_rx(ps2dev->serio);

	ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;

	ps2dev->cmdcnt = receive;
@@ -210,14 +229,14 @@ int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command) 
	 * ACKing the reset command, and so it can take a long

	 * time before the ACK arrives.

	 */

	if (ps2_sendbyte(ps2dev, command & 0xff,

	if (ps2_do_sendbyte(ps2dev, command & 0xff,

			    command == PS2_CMD_RESET_BAT ? 1000 : 200)) {

		serio_pause_rx(ps2dev->serio);

		goto out_reset_flags;

	}



	for (i = 0; i < send; i++) {

		if (ps2_sendbyte(ps2dev, param[i], 200)) {

		if (ps2_do_sendbyte(ps2dev, param[i], 200)) {

			serio_pause_rx(ps2dev->serio);

			goto out_reset_flags;

		}
@@ -253,6 +272,12 @@ int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command) 
	ps2dev->flags = 0;

	serio_continue_rx(ps2dev->serio);



	dev_dbg(&ps2dev->serio->dev,

		"%02x [%*ph] - %x/%08lx [%*ph]\n",

		command & 0xff, send, send_param,

		ps2dev->nak, ps2dev->flags,

		receive, param ?: send_param);



	return rc;

}

EXPORT_SYMBOL(__ps2_command);
@@ -296,6 +321,7 @@ int ps2_sliced_command(struct ps2dev *ps2dev, u8 command) 
	}



out:

	dev_dbg(&ps2dev->serio->dev, "%02x - %d\n", command, retval);

	ps2_end_command(ps2dev);

	return retval;

}