Re: [4.12 regression] Thinkpad X250 Touchpad and Trackpoint not recognized anymore; commit e839ffa: "Input: synaptics - add support for Intertouch devices"

[Benjamin Tissoires <benjamin.tissoires@redhat.com>]

On May 20 2017 or thereabouts, Dmitry Torokhov wrote:
> On Sat, May 20, 2017 at 11:59:50AM +0200, Benjamin Tissoires wrote:
> > Hi,
> > 
> > On May 20 2017 or thereabouts, Pascal Wichmann wrote:
> > > > Looks like you running your patched kernel?
> > > That's right.
> > > 
> > > 
> > > >>> CONFIG_RMI4_CORE=m
> > > >>> CONFIG_RMI4_I2C=m
> > > >>> CONFIG_RMI4_SPI=m
> > > >>> # CONFIG_RMI4_SMB is not set
> > > >
> > > > This is your issue I believe.
> > > 
> > > Indeed, enabling that configuration solves that issue.
> > > 
> > > However, I think it is quite unintuitive that a module (psmouse) chooses
> > > a default mode which requires another driver which is not necessarily
> > > included; though it would probably be not a very clean solution to
> > > explicitly check that as well.
> > > 
> > > Is this behaviour, that one module requires another without
> > > communicating that clearly, wanted?
> > > 
> > 
> > I can see 3 solutions:
> > 1. Have PS2_SMBUS depending on RMI_SMBUS (and ELAN_I2C, and others when
> >    required)
> > 2. Have PS2_SMBUS selecting RMI_SMBUS (and the others when time comes)
> > 3. Changing the default value of synaptics_intertouch to
> >    SYNAPTICS_INTERTOUCH_OFF when RMI_SMBUS is not set
> > 
> > Solution 3. might be interesting because it doesn't prevent users to
> > compile the module on the side and is Synaptics only.
> > 
> > Dmitry, any comments?
> 
> I like #3. We might also want to stick a warning into synaptics.c when
> we see a device that has intertouch, but RMI_SMBUS is disabled, so we
> could nudge users to switch over to RMI.
> 

OK, thanks. See the following series that should have all of this.

Cheers,
Benjamin