[alsa-devel] Headset button mapping in the kernel

[Curtis Malainey]

On Tue, Dec 3, 2019 at 4:34 PM Pierre-Louis Bossart
<pierre-louis.bossart at linux.intel.com> wrote:
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> >> It appears some have started landing
> >> upstream ae09a4783b9caf9307f303ef039f8297ce0371fe ("ASoC: Intel: Headset
> >> button support in kabylake machine driver") but it would be great if
> >> we had
> >> a way for userspace to configure these buttons similar to how we handle
> >> UCMs.
> >
> > The question why you need to change this settings in the user space. I
> > think that the device tree was designed exactly to describe this hw
> > platform specific settings. Another possibility is to use the kernel
> > module option to configure the settings from the user space. But it's
> > just an idea. You are probably looking for an interface which can be
> > used when the driver is running.
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> I am also unclear on the ask.
> We've cleaned-up all machine drivers so that the mapping is identical,
> except for the cases where the codec inverts the buttons.
> Are you saying you do an additional remapping of those buttons in
> userpace? If yes, why not fix the machine driver? The mapping is
> typically based on measured impedance, not really something userspace
> should really know about.
This is something we were under the impression upstream did not want.
Dylan can you clarify our stance here? If we can just add the changes
to the kernel then this would be a no-op.
> Or is this a case where the ChromeOS kernel has not yet seen the
> upstream patches?