Previously, we checked hidraw devices against drivers by using the
HIDIOCGRAWINFO ioctl. While this works, it's not ideal for doing unit
tests since umockdev would have to implement hidraw ioctls.
The new approach uses the HID_ID property on the parent hid device,
which contains the VID/PID pair.
Some USB transfer callbacks in this driver were freeing their transfer
buffer in their callbacks, which causes a double free since the transfer
itself frees them afterwards. Probably just got missed during the V2 api
changes.
This is primarily useful for SPI devices. These devices sometimes needs
a combination of an SPI and HID device, so discovery is a bit more
complicated.
Matthew Mirvish