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SubjectRe: [PATCH v3 4/4] input: alps: Fix trackstick detection
Date
On Sunday 09 November 2014 09:05:04 Dmitry Torokhov wrote:
> Hi Pali,
>
> On Sun, Nov 02, 2014 at 12:25:10AM +0100, Pali Rohár wrote:
> > int alps_detect(struct psmouse *psmouse, bool
> > set_properties) {
> >
> > - struct alps_data dummy;
> > + unsigned char e6[4];
> >
> > - if (alps_identify(psmouse, &dummy) < 0)
> > - return -1;
> > + /*
> > + * Try "E6 report".
> > + * ALPS should return 0,0,10 or 0,0,100 if no buttons are
> > pressed. + * The bits 0-2 of the first byte will be 1s if
> > some buttons are + * pressed.
> > + */
> > + if (alps_rpt_cmd(psmouse, PSMOUSE_CMD_SETRES,
> > + PSMOUSE_CMD_SETSCALE11, e6))
> > + return -EIO;
> > +
> > + if ((e6[0] & 0xf8) != 0 || e6[1] != 0 || (e6[2] != 10 &&
> > e6[2] != 100)) + return -EINVAL;
> >
> > if (set_properties) {
> >
> > + /*
> > + * NOTE: To detect model and trackstick presence we
need
> > to do + * full device reset. To speed up
detection
> > and prevent + * calling duplicate initialization
> > sequence (both in + * alps_detect() and
> > alps_init()) we set model/protocol + * version and
> > correct name in alps_init() (which will + * do
full
> > device reset). For now set name to DualPoint. + */
> >
> > psmouse->vendor = "ALPS";
> >
> > - psmouse->name = dummy.flags & ALPS_DUALPOINT ?
> > - "DualPoint TouchPad" : "GlidePoint";
> > - psmouse->model = dummy.proto_version << 8;
> > + psmouse->name = "DualPoint TouchPad";
> >
> > }
> >
> > +
> >
> > return 0;
>
> We can't do this; going by e6 only will give us false
> positives and alps_detect is supposed to be authoritative.
>
> Thanks.

psmouse-base.c is calling alps_detect() and alps_init()
consecutively so it does not matter if code is in _detect or
_init function. Just need to make sure that correct order will be
used. So this patch could not bring any problems.

If psmouse-base.c detect device false-positive as ALPS (with
alps_detect()) then it immediately calls alps_init() which fails
and psmouse-base.c will try to use another protocol.

--
Pali Rohár
pali.rohar@gmail.com
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