On Wed, Oct 07, 2015 at 06:12:42PM -0700, Andrew Duggan wrote:

I can confirm that it is working on the Dell XPS 13 and the buttonpad
property is set correctly. However, I also tried it on an older non
production precision touchpad and it didn't work. It reports that it fails
to fetch feature 8 and then doesn't report any input. I'm concerned that
some of the early PTPs in some Dell and Acer systems might not work with
this change. I'll test this tomorrow on a few more systems to see if the
problem is isolated to just this one non production touchpad.

Thanks for testing.

[ 2969.222125] usb 1-1: New USB device found, idVendor=06cb, idProduct=2393
[ 2969.222128] usb 1-1: New USB device strings: Mfr=0, Product=2,
SerialNumber=0
[ 2969.222130] usb 1-1: Product: Synaptics T Pad V 01.31
[ 2974.223578] hid-multitouch 0003:06CB:2393.0008: failed to fetch feature 8
[ 2979.226037] hid-multitouch 0003:06CB:2393.0008: failed to fetch feature 8
[ 2979.226137] input: Synaptics T Pad V 01.31 UNKNOWN as /devices/pci0000:00/0000:00:14.0/usb1/1-1/1-1:1.0/0003:06CB:2393.0008/input/input34
[ 2979.226431] hid-multitouch 0003:06CB:2393.0008: input,hiddev0,hidraw2:
USB HID v1.11 Mouse [Synaptics T Pad V 01.31] on usb-0000:00:14.0-1/input0

Without the patch is it successfully retrieving feature 8?

It may be that it has HID_QUIRK_NO_INIT_REPORTS set via quirks in usbhid
which causes the driver to fetch the report in mt_feature_mapping() and
previously it did not do that.