linux-kernel - Re: [PATCH] input: alps-fix the issue alps cs19 trackstick do not work.

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Date:   Mon, 27 May 2019 12:09:13 +0200
From:   Pali Rohár <pali.rohar@...il.com>
To:     XiaoXiao Liu <sliuuxiaonxiao@...il.com>
Cc:     dmitry.torokhov@...il.com, peter.hutterer@...-t.net,
        hui.wang@...onical.com, linux-input@...r.kernel.org,
        linux-kernel@...r.kernel.org, xiaojian.cao@...alps.com,
        zhangfp1@...ovo.com, xiaoxiao.liu-1@...alps.com
Subject: Re: [PATCH] input: alps-fix the issue alps cs19 trackstick do not
 work.

Hi!

On Monday 27 May 2019 05:44:22 XiaoXiao Liu wrote:
> The alps devices which detected to use the ALPS_PROTO_V8 procotol contains
> ALPS touchpad and ALPS trackstick.The ALPS_PROTO_V8 procotol do not
> support the trackstick device process by default.

Normally PS/2 device handled by alps.c is touchpad and in some cases
touchpad sends also trackstick data in that one PS/2 channel.

Does it mean that your device (reported to kernel) sends only trackstick
packets and not touchpad?

> When the trackstick was detected to use ALPS_PROTO_V8 procotol,
> the v8 process_packet method alps_process_packet_ss4_v2 will reject to
> report the data when the device using ALPS_PROTO_V8 procotol is not set
> the ALPS_DUALPOINT flag.
> 
> The alps cs19 trackstick is detected to use the ALPS_PROTO_V8 procotol
> but without ALPS_DUALPOINT flag, the alps driver will not report the
> input data. so the trackstick will not work.
> 
> solution: when the alps cs19 device detected, set the device
> ALPS_DUALPOINT flag,then the input data will be processed.
> 
> Signed-off-by: XiaoXiao Liu <sliuuxiaonxiao@...il.com>
> ---
>  drivers/input/mouse/alps.c | 25 +++++++++++++++++++++++--
>  1 file changed, 23 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c
> index 0a6f7ca883e7..a54677cf7474 100644
> --- a/drivers/input/mouse/alps.c
> +++ b/drivers/input/mouse/alps.c
> @@ -24,7 +24,7 @@
>  
>  #include "psmouse.h"
>  #include "alps.h"
> -
> +#include "trackpoint.h"
>  /*
>   * Definitions for ALPS version 3 and 4 command mode protocol
>   */
> @@ -220,6 +220,23 @@ static bool alps_is_valid_first_byte(struct alps_data *priv,
>  	return (data & priv->mask0) == priv->byte0;
>  }
>  
> +static int alps_check_cs19_trackstick(struct psmouse *psmouse)
> +{
> +	u8 param[2] = { 0 };
> +	int error;
> +
> +	error = ps2_command(&psmouse->ps2dev,
> +			    param, MAKE_PS2_CMD(0, 2, TP_READ_ID));
> +	if (error)
> +		return error;
> +
> +	if (param[0] == TP_VARIANT_ALPS && param[1] & 0x20) {

I guess that you want parenthesis around (param[1] & 0x20). And also
describe what that 0x20 constant means.

> +		psmouse_warn(psmouse, "It is alps cs19 trackstick");

It is not a warning.

> +		return 0;
> +	}
> +	return -1;
> +}
> +
>  static void alps_report_buttons(struct input_dev *dev1, struct input_dev *dev2,
>  				int left, int right, int middle)
>  {
> @@ -2568,8 +2585,12 @@ static int alps_update_dual_info_ss4_v2(unsigned char otp[][4],
>  			alps_exit_command_mode(psmouse);
>  			ps2_command(ps2dev, NULL, PSMOUSE_CMD_ENABLE);
>  
> -			if (reg_val == 0x0C || reg_val == 0x1D)
> +			if (reg_val == 0x0C || reg_val == 0x1D) {

Hm... why your device does not match these constants?

> +				is_dual = true;
> +			} else if (alps_check_cs19_trackstick(psmouse) == 0) {
> +				//For support Thinkpad CS19 TrackStick
>  				is_dual = true;
> +			}
>  		}
>  	}
>  

-- 
Pali Rohár
pali.rohar@...il.com