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SubjectRe: [PATCH 5/7] Input: libps2 - add debugging statements

Hi,

the patch series looks nice, but best to also include the procedure
described here in Documentation/input somewhere. I would not expect
everyone to dig into git commit logs to find the howto :)

Best regards,
Ulrik


On Fri, Jan 19, 2018 at 11:41:09AM -0800, Dmitry Torokhov wrote:
> Date: Fri, 19 Jan 2018 11:41:09 -0800
> From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> To: Benjamin Tissoires <benjamin.tissoires@redhat.com>, Hans de Goede
> <hdegoede@redhat.com>, Lyude Paul <lyude@redhat.com>
> Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
> Subject: [PATCH 5/7] Input: libps2 - add debugging statements
> X-Mailer: git-send-email 2.16.0.rc1.238.g530d649a79-goog
> X-Mailing-List: linux-input@vger.kernel.org
>
> 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>
> ---
> drivers/input/serio/libps2.c | 52 +++++++++++++++++++++++++++++++++-----------
> 1 file changed, 39 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/input/serio/libps2.c b/drivers/input/serio/libps2.c
> index e96ae477f0b56..82befae4dab04 100644
> --- a/drivers/input/serio/libps2.c
> +++ b/drivers/input/serio/libps2.c
> @@ -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,
> - command == PS2_CMD_RESET_BAT ? 1000 : 200)) {
> + 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;
> }
> --
> 2.16.0.rc1.238.g530d649a79-goog
>
> --
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