> -----Original Message-----
> From: Benjamin Tissoires [mailto:[email protected]]
> Sent: Tuesday, September 23, 2014 8:12 AM
> To: Jason Gerecke
> Cc: [email protected]; [email protected]; [email protected];
> Jason Gerecke
> Subject: Re: [PATCH] HID: input: Finish TransducerSerialNumber
> implementation
>
> Hi Jason,
>
> On Sep 22 2014 or thereabouts, Jason Gerecke wrote:
> > The commit which introduced TransducerSerialNumber (368c966) is
> > missing two crucial implementation details. Firstly, the commit does
> > not set the type/code/bit/max fields as expected later down the code
> > which can cause the driver to crash when a tablet with this usage is
> > connected. Secondly, the code to send a MSC_SERIAL event to userspace
> > when this usage is seen in a report is nowhere to be found. This commit
> addresses both issues.
> >
> > Signed-off-by: Jason Gerecke <[email protected]>
> > ---
> > drivers/hid/hid-input.c | 9 +++++++++
> > 1 file changed, 9 insertions(+)
> >
> > diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index
> > 2619f7f..abed624 100644
> > --- a/drivers/hid/hid-input.c
> > +++ b/drivers/hid/hid-input.c
> > @@ -690,6 +690,10 @@ static void hidinput_configure_usage(struct
> > hid_input *hidinput, struct hid_fiel
> >
> > case 0x5b: /* TransducerSerialNumber */
> > set_bit(MSC_SERIAL, input->mscbit);
> > + usage->type = EV_MSC;
> > + usage->code = MSC_SERIAL;
> > + bit = input->mscbit;
> > + max = MSC_MAX;
> > break;
> >
> > default: goto unknown;
> > @@ -1041,6 +1045,11 @@ void hidinput_hid_event(struct hid_device *hid,
> struct hid_field *field, struct
> > input_event(input, EV_KEY, BTN_TOUCH, value > a + ((b - a)
> >> 3));
> > }
> >
> > + if (usage->hid == (HID_UP_DIGITIZER | 0x005b)) { /*
> TransducerSerialNumber */
> > + input_event(input, EV_MSC, MSC_SERIAL, value);
> > + return;
> > + }
> > +
>
> Are you sure that the generic call to
> "input_event(input, usage->type, usage->code, value);" in the end of
> hidinput_hid_event() is not sufficient enough?
>
> As long as the usage/code are set in the hid_usage struct, you should be fine.
>
> Cheers,
> Benjamin
>
Hmmm... This might be an issue with the HID descriptor, actually. It looks like
my hardware doesn't set the logical minimum and maximum for the field, so the
(quite out-of-range) value is ignored. I start seeing data after patching the
descriptor to add these in, but the code is set to MSC_PULSELED instead of
MSC_SERIAL. I suspect that the existing call to 'set_bit' in the
TransducerSerialNumber case is to blame (which makes it act like 'map_foo'
instead of 'map_foo_clear').
Updated patch forthcoming...
Jason
> > if (usage->hid == (HID_UP_PID | 0x83UL)) { /* Simultaneous Effects
> Max */
> > dbg_hid("Maximum Effects - %d\n",value);
> > return;
> > --
> > 2.1.0
> >
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