Re: ALPS touchpad ot correctly recognized: GlidePoint vs DualPoint

["Pali Rohár" <pali.rohar@gmail.com>]

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On Sunday 04 February 2018 20:39:06 Juanito wrote:
> On 02/04/2018 07:16 PM, Pali Rohár wrote:
> > On Monday 11 September 2017 13:26:30 Juanito wrote:
> >> Hi Masaki Ota,
> >>
> >> Thanks!
> >>
> >> On 11.09.2017 04:38, Masaki Ota wrote:
> >>> 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,
> 
> > 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!
> 
> > 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

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