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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: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Dmitry Torokhov 2018-01-02 12:21:49 -08:00
parent 08be954b7a
commit 147b903da6
1 changed files with 42 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

56
drivers/input/serio/libps2.c
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@ -26,6 +26,31 @@ MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
MODULE_DESCRIPTION("PS/2 driver library");
MODULE_LICENSE("GPL");
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);
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));
serio_pause_rx(ps2dev->serio);
ps2dev->flags &= ~PS2_FLAG_ACK;
serio_continue_rx(ps2dev->serio);
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
@ -36,21 +61,12 @@ MODULE_LICENSE("GPL");
int ps2_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout)
{
serio_pause_rx(ps2dev->serio);
ps2dev->nak = 1;
ps2dev->flags |= PS2_FLAG_ACK;
serio_continue_rx(ps2dev->serio);
int retval;
if (serio_write(ps2dev->serio, byte) == 0)
wait_event_timeout(ps2dev->wait,
!(ps2dev->flags & PS2_FLAG_ACK),
msecs_to_jiffies(timeout));
retval = ps2_do_sendbyte(ps2dev, byte, timeout);
dev_dbg(&ps2dev->serio->dev, "%02x - %x\n", byte, ps2dev->nak);
serio_pause_rx(ps2dev->serio);
ps2dev->flags &= ~PS2_FLAG_ACK;
serio_continue_rx(ps2dev->serio);
return -ps2dev->nak;
return retval;
}
EXPORT_SYMBOL(ps2_sendbyte);
@ -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;
}