For each device that can be mapped (touchscreens, tablets), the output
will be fetched from settings and matched with the currently connected
ones. If a match is found, the device matrix will be found out from the
output configuration and set on the device.
This is also updated both individually for newly connected devices, and
collectively on output configuration changes.
https://bugzilla.gnome.org/show_bug.cgi?id=739397
This goes through modifying XI2 device properties, either common ones (eg.
set on every device) or those specific to the libinput X11 driver. Keyboard
repeat/rate are set through core and XKB APIs.
https://bugzilla.gnome.org/show_bug.cgi?id=739397
This object internally keeps track of the relevant input configuration,
and goes through its vmethods in order to apply the configuration on the
backend-specific devices.
So far, only mouse/touchpad settings are actually attached to GSettings
changes. ::set_matrix(), meant for tablets/touchscreens, is not hooked
yet.
One caveat is that meta_input_settings_create() may return NULL if the
backend does not own the windowing system (wayland nested on X11 being
the one case), and thus device settings can't be changed freely.
https://bugzilla.gnome.org/show_bug.cgi?id=739397
