Re: [DIGImend-devel] [PATCH 4/4] HID: uclogic: name the input nodes based on their tool

[Dan R. <ade...@gm...>]

On Feb 25, 2015 12:58 PM, "Benjamin Tissoires" <
ben...@re...> wrote:
>
> Hi Dan,
>
> On Feb 25 2015 or thereabouts, Dan Roberts wrote:
> > If you'll please excuse my ignorance, I'm not in a position to
thoroughly
> > confirm this for a few hours, and I wanted to comment ASAP. I believe
> > hid_input->name does not get freed. It directly points to the embedded
> > array in the hid_device, assigned in hidinput_allocate (). So I think it
> > makes more sense to modify hid_device->name?
>
> No, and no :)
>
> So, the string will get freed because it is allocated with the managed
> ressource (devm_kzalloc). As soon as the device gets destroyed, it will
> free all of the associated memory.

So it is, my brain missed that it wasn't a plain kzalloc().

> The problem of changing hid_device->name is that the name is shared
> between all subdevices that are created. We create one subdevice per
> report, so they will all have a different name. Last, the hid name is
> the one presented for the hidraw node and in some cases (not here
> actually), the kernel can show the hidraw node first and then later the
> input node. If we change the hidraw node in the back of the user, that
> would not be of the best effect.
>
> Cheers,
> Benjamin

Thanks for the explanation and sorry for the noise.

Cheers,
Dan

> >
> > Thanks,
> > Dan
> > We append "Pen", "Pad", "Mouse" or "Keyboard" suffix to the appropriate
> > input node to match what the Wacom driver does and be more convenient
for
> > the user to know which one is which.
> >
> > Signed-off-by: Benjamin Tissoires <ben...@re...>
> > ---
> >  drivers/hid/hid-uclogic.c | 40 ++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 40 insertions(+)
> >
> > diff --git a/drivers/hid/hid-uclogic.c b/drivers/hid/hid-uclogic.c
> > index c03e076..7042238 100644
> > --- a/drivers/hid/hid-uclogic.c
> > +++ b/drivers/hid/hid-uclogic.c
> > @@ -713,6 +713,45 @@ static __u8 *uclogic_report_fixup(struct hid_device
> > *hdev, __u8 *rdesc,
> >         return rdesc;
> >  }
> >
> > +static void uclogic_input_configured(struct hid_device *hdev,
> > +               struct hid_input *hi)
> > +{
> > +       char *name;
> > +       const char *suffix = NULL;
> > +       struct hid_field *field;
> > +       size_t len;
> > +
> > +       /* no report associated (HID_QUIRK_MULTI_INPUT not set) */
> > +       if (!hi->report)
> > +               return;
> > +
> > +       field = hi->report->field[0];
> > +
> > +       switch (field->application) {
> > +       case HID_GD_KEYBOARD:
> > +               suffix = "Keyboard";
> > +               break;
> > +       case HID_GD_MOUSE:
> > +               suffix = "Mouse";
> > +               break;
> > +       case HID_GD_KEYPAD:
> > +               suffix = "Pad";
> > +               break;
> > +       case HID_DG_PEN:
> > +               suffix = "Pen";
> > +               break;
> > +       }
> > +
> > +       if (suffix) {
> > +               len = strlen(hdev->name) + 2 + strlen(suffix);
> > +               name = devm_kzalloc(&hi->input->dev, len, GFP_KERNEL);
> > +               if (name) {
> > +                       snprintf(name, len, "%s %s", hdev->name,
suffix);
> > +                       hi->input->name = name;
> > +               }
> > +       }
> > +}
> > +
> >  /**
> >   * Enable fully-functional tablet mode and determine device parameters.
> >   *
> > @@ -906,6 +945,7 @@ static struct hid_driver uclogic_driver = {
> >         .probe = uclogic_probe,
> >         .report_fixup = uclogic_report_fixup,
> >         .raw_event = uclogic_raw_event,
> > +       .input_configured = uclogic_input_configured,
> >  };
> >  module_hid_driver(uclogic_driver);
> >
> > --
> > 2.1.0
> >
> >
> >
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