On Thu, Apr 27, 2017 at 8:09 AM, Benjamin Tissoires
<benjamin.tissoires@xxxxxxxxxx> wrote:
> On Apr 27 2017 or thereabouts, Jarkko Nikula wrote:
>> Vendor specific handling in hid_scan_report() overrides the hid->group
>> to HID_GROUP_WACOM for all devices with vendor ID equal to
>> USB_VENDOR_ID_WACOM.
>>
>> However there is an i2c-hid multitouch compatible Wacom touschreen which
>> is parsed as generic HID_GROUP_MULTITOUCH_WIN_8 device but
>> hid-multitouch doesn't probe because of this overriding.
>>
>> Support this touschreen by overring the group only when the bus is
>> different than I2C.
>>
>> Signed-off-by: Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx>
>> ---
>> I'm not an HID expert and I don't know is there any existing Wacom
>> tablets using the I2C bus. There are USB and Bluetooth tablets so that's
>
> I'd say there are other I2C Wacom tablets. Jason and Ping can confirm.
>
Absolutely. There are a number of I2C tablets out there. The device
table for wacom.ko includes "{ I2C_DEVICE_WACOM(HID_ANY_ID) }" so that
we can attempt to handle them.
>> the reason I'm checking id->bus != BUS_I2C when overring the group.
>> I've done only basic testing that device is registered as an
>> hid-multitouch device and "hexdump /dev/input/eventX" produces a bunch
>> of hexadecimals when touschscreen is touched.
>
> What's the issue of having wacom.ko loaded for this particular
> touchscreen? wacom.ko should handle it properly.
>
> Cheers,
> Benjamin
>
I'm wondering the same thing. It looks like the vendor-specific
overrides occur after HID_GROUP_MULTITOUCH_WIN_8 would have been
set... Is the wacom module not a part of your kernel?
Jason
---
Now instead of four in the eights place /
you’ve got three, ‘Cause you added one /
(That is to say, eight) to the two, /
But you can’t take seven from three, /
So you look at the sixty-fours....
>> ---
>> drivers/hid/hid-core.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
>> index d162f0dc76e3..cfb0b7262de7 100644
>> --- a/drivers/hid/hid-core.c
>> +++ b/drivers/hid/hid-core.c
>> @@ -816,7 +816,8 @@ static int hid_scan_report(struct hid_device *hid)
>> */
>> switch (hid->vendor) {
>> case USB_VENDOR_ID_WACOM:
>> - hid->group = HID_GROUP_WACOM;
>> + if (hid->bus != BUS_I2C)
>> + hid->group = HID_GROUP_WACOM;
>> break;
>> case USB_VENDOR_ID_SYNAPTICS:
>> if (hid->group == HID_GROUP_GENERIC)
>> --
>> 2.11.0
>>
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