commit f5d07b9e98 upstream.
Lenovo introduced trackpoint compatible sticks with minimum PS/2 commands.
They supposed to reply with 0x02, 0x03, or 0x04 in response to the
"Read Extended ID" command, so we would know not to try certain extended
commands. Unfortunately even some trackpoints reporting the original IBM
version (0x01 firmware 0x0e) now respond with incorrect data to the "Get
Extended Buttons" command:
thinkpad_acpi: ThinkPad BIOS R0DET87W (1.87 ), EC unknown
thinkpad_acpi: Lenovo ThinkPad E470, model 20H1004SGE
psmouse serio2: trackpoint: IBM TrackPoint firmware: 0x0e, buttons: 0/0
Since there are no trackpoints without buttons, let's assume the trackpoint
has 3 buttons when we get 0 response to the extended buttons query.
Signed-off-by: Aaron Ma <aaron.ma@canonical.com>
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=196253
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
4a6e9e328c