Re: [PATCH FIX for 4.0 0/2] alps: Report alps v2 Dualpoint Stick events via the right event node

["Pali Rohár" <pali.rohar@gmail.com>]

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On Wednesday 01 April 2015 18:14:43 Hans de Goede wrote:
> Hi,
> 
> On 01-04-15 18:11, Pali Rohár wrote:
> > On Wednesday 01 April 2015 17:44:04 Hans de Goede wrote:
> >> Hi Dmitry & Pali,
> >> 
> >> While working on some libinput code to deal with
> >> trackpoints of different model laptops having quite
> >> different speed / sensitivity ootb, I noticed that with
> >> the current 4.0-rc# kernels the trackpoint events on
> >> laptops with a PROTO_V2 alps touchpad are no longer being
> >> send by the "Dualpoint Stick" event node, instead a new
> >> "ALPS PS/2 Mouse" node gets created and sends the
> >> trackpoint events.
> >> 
> >> The cause of this is that the stick on these devices sends
> >> bare ps/2 packets as data.
> >> 
> >> Although this does not really break anything (atm, it does
> >> break my libinput work), it is still wrong, esp. also since
> >> the "Dualpoint Stick" node has the POINTING_STICK property
> >> set, where as the "ALPS PS/2 Mouse" node which is actually
> >> sending the stick events does not.
> >> 
> >> If still possible I would like to see this fixes added to
> >> 4.0, if not we should queue them up for stable.
> >> 
> >> Regards,
> >> 
> >> Hans
> > 
> > Hi Hans, thanks for testing!
> > 
> > I would like to see this observation also in alps protocol
> > documentation, where is all information how are data from
> > touchpads and tracksticks reported.
> 
> Good point, for today I'm already a bit late with logging
> off, but I'll do a follow up patch for this tomorrow.
> 
> > Also for me it it makes sense to squash both patches into
> > one.
> 
> I think having them separate is slightly better, but either
> way is fine with me,
> 
> > And can you check if your change is needed only for
> > ALPS_PS2_INTERLEAVED devices? For me it looks like that only
> > those alps devices could mix both 3-bytes and 6-bytes
> > packets...
> 
> That is what I expected in the beginning too, but no that is
> not the case, this happens on my Latitude D620 too, and that
> one does not use / set ALPS_PS2_INTERLEAVED.
> 

Ok. It really needs documentation.

And I'm also for including fix to 4.0 stable kernel as this is 
regression for those dell models.

> Regards,
> 
> Hans
> 
> p.s.
> 
> Talking about ALPS_PS2_INTERLEAVED did you ever try that on
> the current troublesome models which sometime get out of
> sync?
> 
> Maybe they are actually interleaving things again ?
> 
> Regards,
> 
> Hans

No, there are no interleaved packets. All packets are 6-bytes 
length, but some have swapped bits... When I saw those lot of 
invalid packets I thought it is similar to ALPS_PS2_INTERLEAVED. 
But not.

-- 
Pali Rohár
pali.rohar@gmail.com

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