Re: ALPS v7 trackpad passthrough to Thinkpad trackpoint

["Pali Rohár" <pali.rohar@gmail.com>]

On Thursday 13 August 2015 18:25:16 Vadim Klishko wrote:
> > On Thu, Aug 13, 2015 at 06:11:22PM -0600, Vadim Klishko wrote:
> >> I am not sure I understand what details you are looking for, but as
> >> far as I know, the only way a command sent to an Alps device from the
> >> host could reach the trackstick is when the touchpad chip is in
> >> pass-thru mode.
> > 
> > We are looking for information on how to detect whether a device
> > supports pass-through mode and how to activate it. IOW we are looking
> > for the protocol specs for the PS/2 flavor used by ALPS devices. So far
> > we had to deduce many of the details itself and it would be great if
> > manufacturer would share the information with us sol that we could
> > improve support for the devices in Linux kernel.
> > 
> OK, got it. It may take some time.
> 

Hi Vadim! Now after more months, do you have some news about this?

> 
> >> 
> >> 
> >> ----- Original Message ----- 
> >> From: "Dmitry Torokhov" <dmitry.torokhov@gmail.com>
> >> To: "Pali Rohár" <pali.rohar@gmail.com>
> >> Cc: "Ari Entlich" <atrigent@gmail.com>; <linux-input@vger.kernel.org>; "Masaki Ota" <012nexus@gmail.com>; "Tommy Will" <tommywill2011@gmail.com>; "Yunkang Tang" <yunkang.tang@cn.alps.com>; "Qiting Chen" <qiting.chen@cn.alps.com>; "Qiting Chen" <elaineee66@gmail.com>; <vadim@cirque.com>
> >> Sent: Thursday, August 13, 2015 4:48 PM
> >> Subject: Re: ALPS v7 trackpad passthrough to Thinkpad trackpoint
> >> 
> >> 
> >> > On Thu, Aug 13, 2015 at 01:03:17PM +0200, Pali Rohár wrote:
> >> >> On Friday 07 August 2015 12:35:33 Ari Entlich wrote:
> >> >> > On Fri, Aug 7, 2015 at 10:12 AM, Pali Rohár <pali.rohar@gmail.com> wrote:
> >> >> > > For some old ALPS devices which use V1 and V2 protocols (with flag
> >> >> > > ALPS_PASS) there is something like that. On that devices touchpad is
> >> >> > > behind trackpoint HW. But you cannot wait for data or poll for both
> >> >> > > devices at same time -- you need to choose if tou want to talk directly
> >> >> > > to touchpad (via passthrough mode) or just to trackpoint. I think
> >> >> > > because of this limitation ALPS driver implement all logic in one
> >> >> > > driver...
> >> >> > >
> >> >> > > Above was for old ALPS devices. New ALPS devices with V3 or V5 protocols
> >> >> > > have trackpoint behind touchpad, so normally OS communicate with
> >> >> > > touchpad (and not with trackstick like before). But here touchpad sends
> >> >> > > data for both touchpad and trackstick events and so OS does not have
> >> >> > > normal access to "hidden" trackstick.
> >> >> > >
> >> >> > > There is a way "jump" into passthrough mode and talk directly to
> >> >> > > trackpoint. But it is used only for configuring trackstick and currently
> >> >> > > it is used to configure trackstick so it send data (via touchpad) in
> >> >> > > format which is supported by our ALPS driver.
> >> >> > >
> >> >> > > On the other hand, synaptics driver and devices support full
> >> >> > > "encapsulation" or how can I call it of serio PS/2 device and in this
> >> >> > > case you can use full set of PS/2 commands directly with trackstick
> >> >> > > (behind synaptics touchpad). ALPS devices do not support something like
> >> >> > > that.
> >> >> > 
> >> >> > It looks to me like the Synaptics passthrough is implemented primarily
> >> >> > via the ability to write directly to the trackpoint. Events coming
> >> >> > from the trackpoint are implemented similarly to the ALPS driver - by
> >> >> > redirecting trackpoint events to the second device which the driver
> >> >> > creates for the trackpoint.
> >> >> > 
> >> >> 
> >> >> No, passthrough for ALPS and Synaptics differ. Synaptics driver exports
> >> >> full serio PS/2 bus on which can be attached psmouse.ko driver with full
> >> >> mouse detection (or any other serio driver) and so there can be full
> >> >> TPPS/2 trackpoint.c protocol driver.
> >> >> 
> >> >> ALPS allows us for *some* protocol version passthrough data directly to
> >> >> touchpad (or trackpoint) device. There is no support to exporting full
> >> >> serio bus with PS/2 access to it (like for Synaptics hardware).
> >> > 
> >> > At least we do not know how to detect and activate it even if it exists.
> >> > 
> >> > Let's add some ALPS people to the thread: maybe they could share some
> >> > details on accessing trackpoints behind the touchpads with us.
> >> > 
> >> > Thanks.
> >> > 
> >> > -- 
> >> > Dmitry
> >> 
> >> -- 
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> >> contents to anyone.
> >> Cirque Corporation
> > 
> > -- 
> > Dmitry
> 

-- 
Pali Rohár
pali.rohar@gmail.com
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