Re: [PATCH] platform/x86: fujitsu-laptop: Don't oops when FUJ02E3 is not presnt

[Jonathan Woithe <jwoithe@just42.net>]

On Wed, Oct 25, 2017 at 06:51:31AM +0200, Micha?? K??pie?? wrote:
> > > Finally, it seems the S6120 also has a row of "application panel"
> > > hotkeys above the keyboard, but lacks the FUJ02E3 ACPI device, so I am
> > > wondering whether these hotkeys work in Linux.  Ville, do they?
> > 
> > They work via the apanel driver.
> 
> Oops, then it looks like we have two drivers which poke the same
> hardware at the same time using different methods: apanel uses SMBus,
> fujitsu-laptop uses ACPI (the former is inferior as it resorts to
> polling, which causes key presses to be reported with a delay).  I just
> loaded both drivers on my Fujitsu Lifebook S7020 and it results in
> duplicate events being passed to userspace.  We should probably prevent
> this, but I am not quite sure how to achieve that.

That's a bit tricky.  Evidently some models need the SMBus approach because
they lack the FUJ02E3 device.  However, on systems with the FUJ02E3 the
ACPI method is clearly desirable.  Should apanel disable itself on systems
where an FUJ02E3 is present (although I'm not sure how precisely to arrange
for this to happen)?  Then again, this would only be feasible if the ACPI
method can handle all application panel variations which are seen across the
various models.

Regards
  jonathan