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

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Date:	Thu, 21 Feb 2013 12:02:46 -0800
From:	Kamal Mostafa <kamal@...onical.com>
To:	Dmitry Torokhov <dmitry.torokhov@...il.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, 2013-02-21 at 11:56 -0800, Dmitry Torokhov wrote:
> 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?

No, the other parts are needed also:  The handling of
tp_metrics_supported gets moved so that the default values now get set
first, then overridden only if tp_metrics_supported is true.
Previously, the defaults wouldn't get set if it wasn't true (which was a
bug that never manifested).

 -Kamal


> 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
> > 
> 


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