Re: [PATCH 0/5] HID: wacom: introduce generic HID handling

From: Jason Gerecke
Date: Tue Sep 30 2014 - 19:46:09 EST

On Tue, Sep 30, 2014 at 10:27 AM, Benjamin Tissoires
<benjamin.tissoires@xxxxxxxxxx> wrote:
> On Sep 26 2014 or thereabouts, Jason Gerecke wrote:
>> On Fri, Sep 26, 2014 at 4:03 AM, Jiri Kosina <jkosina@xxxxxxx> wrote:
>> > On Tue, 23 Sep 2014, Benjamin Tissoires wrote:
>> >
>> >> Hi guys,
>> >>
>> >> So, this patch series aims at supporting natively any future HID compliant wacom
>> >> tablet. Those found on the various laptops (ISDv4/5) already are HID compliant
>> >> and they should work in the future without any modification of the kernel.
>> >>
>> >> Few things to note here:
>> >> - I used the PID 0x00E6 found on the Lenovo X230 for the tests
>> >> - I did not removed its entry in the list because there is a slightly different
>> >> behavior while using this patch set: when more than two fingers are on the
>> >> screen, the tablet stops sending finger events, while with the wacom
>> >> proprietary bits, it continues to send them. Besides that, the events emitted
>> >> before and after the patch series are the same (at least on the E6)
>> >> - I can not rely on hid-input directly because wacom wants to be in control of
>> >> the input devices it creates. This might be solved in the future, but for now
>> >> it is just easier to rewrite the few mapping/events handling than trying to
>> >> fit in the hid-input model.
>> >> - there will still be more specific use cases to handle later (see the joke of
>> >> the MS surface 3 pen[1] for instance), but this should give a roughly working
>> >> pen/touch support for those future devices.
>> >>
>> >> Jason, I would be very glad if you could conduct a few tests for this on the
>> >> ISDv4/5 sensors you have.
>> >
>> > I am waiting with this one for testing results from Jason, but if you guys
>> > want this to go in the next merge window, I'd like to ask you not to
>> > postpone the testing too much.
>> >
>> > Thanks.
>> >
>> I'm in the process of capturing traces from hid-record for multiple
>> tablet PCs both pre- and post-patch to locate any obvious issues. My
>> initial results are promising on the pen side (the only things I've
>> noticed so far is the 2nd barrel switch not being supported -- as
>> might be suspected) but less so on the touch side (single-finger
>> devices seem to work fine, but the new code doesn't seem to handle any
>> of the multitouch devices I've tried).
> Do you consider not having the second barrel switch a blocker or can we
> ship it this and send a fix later?
> As for the touch, I tested/developed it on the Lenovo X230. It presents
> a hid-multitouch compatible touch interface, when the feature input_mode
> is sent with the value '2'. By re-reading it, it seems to me that you
> are trying to replay the touch traces you got before the patch, but this
> will not work because the touch protocol is not the same. ISDv4 used to
> rely on the proprietary touch protocol which is hard to describe in HID.
> I would say that as long as there is no regression (actually there can
> not be for old devices :-P), we should still carry this series for 3.18.
> We might need to adjust the bits here and there, but if we can have a
> *basic* support of the tablet out of the box, this is still much better
> than silently ignoring it.
I'm in agreement. The lack of second-switch support was expected and
somewhat trivial at this moment. We can work on finessing it as we go.

Regarding the touch input, I haven't had enough time to dive in to
figuring out what is wrong, but traces aren't the issue (I've not been
able to use traces for multitouch testing because the driver can't
query features->touch_max ;)). Working with actual hardware, I don't
get _any_ events out of the driver when using the touchscreen. I
checked that the device is sending the non-vendor-defined reports,
which does seem to be the case. The descriptor for the reports also
seem to be reasonable, appearing to follow Microsoft's

>> Expect more news next week :)
> So?????
I'm not sure if you want to fix touch first or just get these upstream
and fix during RC (as you said, it won't cause any regressions...) but
I'll give the following:

Acked-by: Jason Gerecke <killertofu@xxxxxxxxx>

Now instead of four in the eights place /
youâve got three, âCause you added one /
(That is to say, eight) to the two, /
But you canât take seven from three, /
So you look at the sixty-fours....

>> PS: I'm pretty sure ISDv5 shouldn't be relied on for HID data :| The
>> descriptor for the Cintiq Companion Hybrid, at least, is like our
>> branded sensors with useful data only in the touchscreen descriptor
>> (the pen descriptor is a bunch of opaque vendor-defined reports). Not
>> sure if the Cintiq Companion is the same though since it runs
>> Windows...
> Ouch. For those, we will need to either fix the report descriptors or
> handle them in the same way you always used to do: manually.
> Cheers,
> Benjamin
>> >>
>> >> [1]
>> >>
>> >> Benjamin Tissoires (5):
>> >> HID: wacom: rename failN with some meaningful information
>> >> HID: wacom: split out input allocation and registration
>> >> HID: wacom: move allocation of inputs earlier
>> >> HID: wacom: implement generic HID handling for pen generic devices
>> >> HID: wacom: implement the finger part of the HID generic handling
>> >>
>> >> drivers/hid/hid-core.c | 3 +
>> >> drivers/hid/wacom.h | 6 +
>> >> drivers/hid/wacom_sys.c | 184 +++++++++++++++++++++--------
>> >> drivers/hid/wacom_wac.c | 299 ++++++++++++++++++++++++++++++++++++++++++++++++
>> >> drivers/hid/wacom_wac.h | 17 +++
>> >> include/linux/hid.h | 2 +
>> >> 6 files changed, 462 insertions(+), 49 deletions(-)
>> >>
>> >> --
>> >> 2.1.0
>> >>
>> >
>> > --
>> > Jiri Kosina
>> > SUSE Labs
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at