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

From: Kamal Mostafa
Date: Thu Feb 21 2013 - 15:02:16 EST


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@xxxxxxxxxxxxx>
> > Cc: Dudley Du <dudl@xxxxxxxxxxx>
> > ---
> > 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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