Re: ALPS touchpad ot correctly recognized: GlidePoint vs DualPoint

On Sunday 04 February 2018 20:39:06 Juanito wrote:

On 02/04/2018 07:16 PM, Pali Rohár wrote:

quoted

On Monday 11 September 2017 13:26:30 Juanito wrote:

quoted

Hi Masaki Ota,

Thanks!

On 11.09.2017 04:38, Masaki Ota wrote:

quoted

Hi, Juanito,

In my information, ALPS Touchpad is used on Thinkpad E series and L series.
I don't know the device that is ALPS Touchpad + other vendor TrackStick.
But Lenovo might use ALPS Touchpad on such a combination.

Well, that is probably my fault, as it is not the original touchpad that
was delievered with the laptop. I bought the touchpad (that included
the three buttons) separately because I didn't like the clickpad that
came with my laptop.

Hi Juanito,

Hi Pali,

quoted

if you are still want to play with your touchpad hardware, I have a good
news for your.

Yeah! I'd love to get it to work! It's just I've been "working" on some
other projects and my last kernel builds didn't work at all so I gave up
and never got back to it.

Thank you very much for that!

quoted

It looks like that at least ALPS rushmore touchpads allow to receive RAW
PS/2 packets from trackstick to host kernel, without modifying them by
touchpad. Plus I was able to tell ALPS touchpad to start "mixing" those
RAW trackstick PS/2 packets with native touchpad packets.

On my configuration trackstick in RAW PS/2 mode by default talks with
standard bare 3 byte PS/2 protocol and touchpad in 6 byte ALPS protocol.
alps.c/psmouse.ko is already able to process and parse such mixed
packets. And trackstick can be switched to some extended 4 byte
protocol...

All this happen when passthrough mode is enabled.

From my understanding it seems that in normal mode, touchpad and
trackstick communicate with that 4 byte protocol and touchpad converts
it into 6 byte ALPS protocol and then send to kernel.

On thinkpads trackstick communicate with TPPS/2 protcol and above 4
byte. So in my opinion ALPS touchpad by default cannot understand it.
But you should be able to enter passthrough mode and then you would
receive that TPPS/2 in alps kernel code.

I don't really understand what you mean. Do I "just" have to set it to
passthrough mode? How exactly can I do that?

Look at function alps_passthrough_mode_v3(). And try to call it after
touchpad is initialized.

You can also look which alps_command_mode_write_reg() functions are
called for your touchpad and maybe try to figure out what those
registers can enabled/disable.

On http://www.cirque.com/gen4-dev-resources you can find document named
GP-AN- 130823 INTERFACING TO GEN4 OVER I2C (PDF) which contains
some description of those registers (in section 7).

Register C2C8, bit 0 has description "PS2AuxControl.CommandPassThruEnabled"

If trackstick is not detected, it seems you can "force" enable it by
setting bit 7 "PS2AuxControl.AuxDevicePresent" in same register.

Again, thank you very much!

Have you tried to read from that register which Masaki Ota talked in
previous emails?

-- 
Pali Rohár
pali.rohar@gmail.com