linux-kernel - Re: [PATCH] Input: fix Cypress PS/2 Trackpad in Dell XPS12

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Date:	Thu, 21 Feb 2013 11:56:30 -0800
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Kamal Mostafa <kamal@...onical.com>
Cc:	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
	Henrik Rydberg <rydberg@...omail.se>,
	Dudley Du <dudl@...ress.com>,
	Kyle Fazzari <git@...tus.e4ward.com>
Subject: Re: [PATCH] Input: fix Cypress PS/2 Trackpad in Dell XPS12

On Thu, Feb 21, 2013 at 10:55:55AM -0800, Kamal Mostafa wrote:
> Avoid firmware glitch in Cypress PS/2 Trackpad firmware version 11
> (as observed in Dell XPS12) which prevents driver from recognizing
> the trackpad.
> 
> BugLink: http://launchpad.net/bugs/1103594
> 
> Signed-off-by: Kamal Mostafa <kamal@...onical.com>
> Cc: Dudley Du <dudl@...ress.com>
> ---
>  drivers/input/mouse/cypress_ps2.c |   19 +++++++++++++------
>  1 file changed, 13 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/input/mouse/cypress_ps2.c b/drivers/input/mouse/cypress_ps2.c
> index 1673dc6..f51765f 100644
> --- a/drivers/input/mouse/cypress_ps2.c
> +++ b/drivers/input/mouse/cypress_ps2.c
> @@ -236,6 +236,13 @@ static int cypress_read_fw_version(struct psmouse *psmouse)
>  	cytp->fw_version = param[2] & FW_VERSION_MASX;
>  	cytp->tp_metrics_supported = (param[2] & TP_METRICS_MASK) ? 1 : 0;
>  
> +	/*
> +	 * Trackpad fw_version 11 (in Dell XPS12) yields a bogus response to
> +	 * CYTP_CMD_READ_TP_METRICS so do not try to use it. LP: #1103594.
> +	 */
> +	if (cytp->fw_version >= 11)
> +		cytp->tp_metrics_supported = 0;
> +

Isn't this the only chunk that is actually needed to fix the issue?

Thanks.

>  	psmouse_dbg(psmouse, "cytp->fw_version = %d\n", cytp->fw_version);
>  	psmouse_dbg(psmouse, "cytp->tp_metrics_supported = %d\n",
>  		 cytp->tp_metrics_supported);
> @@ -258,6 +265,9 @@ static int cypress_read_tp_metrics(struct psmouse *psmouse)
>  	cytp->tp_res_x = cytp->tp_max_abs_x / cytp->tp_width;
>  	cytp->tp_res_y = cytp->tp_max_abs_y / cytp->tp_high;
>  
> +	if (!cytp->tp_metrics_supported)
> +		return 0;
> +
>  	memset(param, 0, sizeof(param));
>  	if (cypress_send_ext_cmd(psmouse, CYTP_CMD_READ_TP_METRICS, param) == 0) {
>  		/* Update trackpad parameters. */
> @@ -315,18 +325,15 @@ static int cypress_read_tp_metrics(struct psmouse *psmouse)
>  
>  static int cypress_query_hardware(struct psmouse *psmouse)
>  {
> -	struct cytp_data *cytp = psmouse->private;
>  	int ret;
>  
>  	ret = cypress_read_fw_version(psmouse);
>  	if (ret)
>  		return ret;
>  
> -	if (cytp->tp_metrics_supported) {
> -		ret = cypress_read_tp_metrics(psmouse);
> -		if (ret)
> -			return ret;
> -	}
> +	ret = cypress_read_tp_metrics(psmouse);
> +	if (ret)
> +		return ret;
>  
>  	return 0;
>  }
> -- 
> 1.7.10.4
> 

-- 
Dmitry
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