InputClass sections use various MatchFoo directives to decide which device to
apply to. This usually works fine for specific snippets but has drawbacks for
snippets that apply more generally to a multitude of devices.
This patch adds a NoMatchFoo directive to negate a match, thus allowing
snippets that only apply if a given condition is not set. Specifically, this
allows for more flexible fallback driver matching, it is now possible to use a
snippet that says "assign driver foo, but only if driver bar wasn't already
assigned to it". For example:
Section "InputClass"
Identifier "libinput for tablets"
MatchIsTablet "true"
NoMatchDriver "wacom"
Driver "libinput"
EndSection
The above only assigns libinput to tablet devices if wacom isn't already
assigned to this device, making it possible to select a specific driver by
installing/uninstalling it.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
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