Re: Input: mouse: Trackpoint middle button not recognized on Thinkpad E470

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Tue, Apr 25, 2017 at 11:16:33PM +0200, ulrik.debie-os@e2big.org wrote:
> Hi Julian, Dmitry,
> 
> I have a similar behaviour for thinkpad e570 trackpoint. Manually forcing 
> button_info also made the middle button work.
> Julian, I planned to go the investigation road just when I happened to see
> your email. 
> 
> Dmitry, what do you suggest as a path forward when
> extended-button-data command fails ? Check for DMI and whitelist 3button
> for certain laptops which will be a growing list (2 laptops known already)? 
> Default to 3 buttons when extended-button-data command fails ?

Hmm.. I do not recall seeing real trackpoints with only 2 buttons. Let's
try defaulting to 3 and see what happens.

> 
> Julian, feel free to propose a patch, I'll review and test on E570.
> 
> Kind regards,
> Ulrik
> 
> 
> 
> On Tue, Apr 25, 2017 at 10:06:56PM +0200, Julian Exner wrote:
> > Date:   Tue, 25 Apr 2017 22:06:56 +0200
> > From: Julian Exner <jexner@techfak.uni-bielefeld.de>
> > To: "linux-input@vger.kernel.org" <linux-input@vger.kernel.org>
> > Cc: aduggan@synaptics.com
> > Subject: Re: Input: mouse: Trackpoint middle button not recognized on
> >  Thinkpad E470
> > X-Mailing-List: linux-input@vger.kernel.org
> > 
> > I checked the Trackpoint specification [1] and apparently 0xFE stands for
> > the Trackpoint controller asking to resend the command due to invalid input.
> > Resending the extended-button-data command results in 0xFC which stands for
> > another invalid input. But 0xFE does not only stand for a resend request but
> > might also mean that the issued command is not implemented in the ROM. [2]
> > 
> > So maybe when the extended-button-data command is not support, we can check
> > for certain Trackpoint or ROM ids to deduce if a middle button is present.
> > If you think this is the right approach I may craft a patch for this.
> > 
> > [1] http://blogs.epfl.ch/icenet/documents/Ykt3Eext.pdf
> > [2] http://blogs.epfl.ch/icenet/documents/Ykt3Eext.pdf#page=20
> > 
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-- 
Dmitry