Hi, I'm working on a touchpad device issue as reported on https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1887190. This touchpad device MSFT0001:00 04F3:Touchpad should be handled by hid_rmi. But currently hid-core.c chooses hid_multitouch by mistake, 1. When scanning this device's report descriptor, HID_DG_CONTACTID usage is found. Thus group HID_GROUP_MULTITOUCH is assigned to the device. 2. The flag HID_SCAN_FLAG_MT_WIN_8 is also found. Thus group HID_GROUP_MULTITOUCH_WIN_8 is assigned to the device. 3. hid-multitouch.c claims handling devices with the group of HID_GROUP_MULTITOUCH_WIN_8 static const struct hid_device_id mt_devices[] = { /* Generic MT device */ { HID_DEVICE(HID_BUS_ANY, HID_GROUP_MULTITOUCH, HID_ANY_ID, HID_ANY_ID) }, /* Generic Win 8 certified MT device */ { .driver_data = MT_CLS_WIN_8, HID_DEVICE(HID_BUS_ANY, HID_GROUP_MULTITOUCH_WIN_8, HID_ANY_ID, HID_ANY_ID) }, { } }; There are several potential solutions, - Let the device vendor fix this problem since this device's report descriptor shouldn't have the HID_DG_CONTACTID usage. - Make it a special case by setting the device's group to HID_GROUP_RMI in hid_scan_report when vendor id and product ID are matched. - hid-quirks.c seems to be designed to handle special cases, is it suitable for this case? Can anyone give an advice on which direction I should take? Thank you! -- Best regards, Coiby
