Just like the K12A the Dell K15A keyboard-dock has problems with
get_feature requests. This sometimes leads to several
"failed to fetch feature 8" messages getting logged, after which the
touchpad may or may not work.

Just like the K15A these errors are triggered by undocking and docking
the tablet.

There also seem to be other problems when undocking and then docking again
in quick succession. It seems that in this case the keyboard-controller
still retains some power from capacitors and does not go through a
power-on-reset leaving it in a confuses state, symptoms of this are:

1. The USB-ids changing to 048d:8910
2. Failure to read the HID descriptors on the second (mouse) USB intf.
3. The touchpad freezing after a while

These problems can all be cleared by undocking the keyboard and waiting
a full minute before redocking it. Unfortunately there is nothing we can
do about this in the kernel.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>