Re: [PATCH v2 4/5] Input: synaptics - Skip quirks when post-2013 dimensions

[Daniel Martin <consume.noise@gmail.com>]

On Fri, Jan 30, 2015 at 10:34:22AM -0500, Benjamin Tissoires wrote:
> On Fri, Jan 30, 2015 at 4:59 AM, Hans de Goede <hdegoede@redhat.com> wrote:
> > Hi,
> >
> > On 01/29/2015 08:50 PM, Benjamin Tissoires wrote:
> >> On Thu, Jan 29, 2015 at 2:02 PM, Benjamin Tissoires
> >> <benjamin.tissoires@gmail.com> wrote:
> >>> Hi Daniel,
> >>>
> >>> On Tue, Jan 27, 2015 at 3:34 AM, Daniel Martin
> >>> <daniel.martin@secunet.com> wrote:
> >>>> From: Daniel Martin <consume.noise@gmail.com>
> >>>>
> >>>> If we queried min/max dimensions of x [1266..5674], y [1170..4684] we
> >>>> have post-2013 model and don't need to apply any quirk.
> >>>>
> >>>> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=91541
> >>>> Signed-off-by: Daniel Martin <consume.noise@gmail.com>
> >>>> ---
> >>>>  drivers/input/mouse/synaptics.c | 5 +++++
> >>>>  1 file changed, 5 insertions(+)
> >>>>
> >>>> diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
> >>>> index 37d4dff..f6c43ff 100644
> >>>> --- a/drivers/input/mouse/synaptics.c
> >>>> +++ b/drivers/input/mouse/synaptics.c
> >>>> @@ -420,6 +420,11 @@ static int synaptics_quirks(struct psmouse *psmouse)
> >>>>         struct synaptics_data *priv = psmouse->private;
> >>>>         int i;
> >>>>
> >>>> +       /* Post-2013 models expose correct dimensions. */
> >>>> +       if (priv->x_min == 1266 && priv->x_max == 5674 &&
> >>>> +           priv->y_min == 1170 && priv->y_max == 4684)
> >>>> +               return 0;
> >>>> +
> >>>
> >>> Well, this one, I don't like it either :(
> >>>
> >>> At least, the test should be within the psmouse_matches_pnp_id() below
> >>> to ensure we are deciding with Lenovo devices only.
> >>>
> >>> The other concern is hardcoding these values in the code directly.
> >>> What if Synaptics/Lenovo decides to ship a new released model with
> >>> proper min_max ranges but with a different offset?
> >>>
> >>> Andrew told us that the board ID should be enough to discriminate old
> >>> and faulty touchpads from the new and valid touchpads.
> >>>
> >>> My concern here is that we will have to backport these changes in the
> >>> various stable kernel and the various distributions. And if we do not
> >>> end up with the right solution right now, that means that we will have
> >>> to do the job over and over.
> >>>
> >>> I am quite tempted to find a solution in the userspace for that fix.
> >>> Not sure I'll be able to find the right one right now, but it may
> >>> worth trying.
> >>>
> >>
> >> So, the user space solution seems difficult because we do not export
> >> either the board_id or the firmware_id. So that would required to
> >> update the kernel anyway, a bunch of user space tools and a hwdb... :(
> >>
> >> How about we just add an extra min/max in struct min_max_quirk,
> >> compare the current min/max with the 2 possible values and if there is
> >> a match, we do not override the values.
> >> This way, we keep the crap of wrong/correct min max in the small list
> >> of device we know are problematic, and if the new batch of E540 has a
> >> different correct min/max range, then we will be able to adjust it
> >> without breaking the other we fixed.
> >>
> >> Dmitry, Hans, any comments on this?
> >
> > I'm thinking more along the lines of adding a max_broken_board_id field
> > to the quirks, and if the touchpad board_id is larger then the
> > max_broken_board_id not use the quirk.
> >
> 
> Yep, this was confirmed by Synaptics that the board id will be
> incremented only at each new board revision. So it should be safe to
> only check for that.

Could you ask your contact for an exact board id, since when the ranges
have been fixed? From the data I can look at it seems to be <= 2962.