evdev: add internal tagging system

For conditional touchpad disabling we need two pieces of knowledge: is the
device an internal touchpad and is another device an external mouse-like
device. For that use-case it's enough to tag any device that's on USB and
Bluetooth with pointer capabilities as external mouse. A more complex can be
done when needed.

The tag function is part of the dispatch interface (to save on udev code) and
called before the caller is notified about the new device, i.e. the device is
fully configured by the time it needs to be tagged, and other devices can rely
on the tags being assigned by the time they get notified about the new device.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>

src/evdev-mt-touchpad.c

@@ -681,6 +681,7 @@ static struct evdev_dispatch_interface tp_interface = {
 	tp_destroy,
 	NULL, /* device_added */
 	NULL, /* device_removed */
+	NULL, /* tag_device */
 };
 
 static void

src/evdev.c

@@ -24,6 +24,7 @@
 #include "config.h"
 
 #include <errno.h>
+#include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
 #include "linux/input.h"
@@ -545,6 +546,19 @@ evdev_need_touch_frame(struct evdev_device *device)
 	return 0;
 }
 
+static void
+evdev_tag_external_mouse(struct evdev_device *device,
+			 struct udev_device *udev_device)
+{
+	int bustype;
+
+	bustype = libevdev_get_id_bustype(device->evdev);
+	if (bustype == BUS_USB || bustype == BUS_BLUETOOTH) {
+		if (device->seat_caps & EVDEV_DEVICE_POINTER)
+			device->tags |= EVDEV_TAG_EXTERNAL_MOUSE;
+	}
+}
+
 static void
 fallback_process(struct evdev_dispatch *dispatch,
 		 struct evdev_device *device,
@@ -578,6 +592,13 @@ fallback_destroy(struct evdev_dispatch *dispatch)
 	free(dispatch);
 }
 
+static void
+fallback_tag_device(struct evdev_device *device,
+		    struct udev_device *udev_device)
+{
+	evdev_tag_external_mouse(device, udev_device);
+}
+
 static int
 evdev_calibration_has_matrix(struct libinput_device *libinput_device)
 {
@@ -624,6 +645,7 @@ struct evdev_dispatch_interface fallback_interface = {
 	fallback_destroy,
 	NULL, /* device_added */
 	NULL, /* device_removed */
+	fallback_tag_device,
 };
 
 static uint32_t
@@ -792,6 +814,7 @@ configure_pointer_acceleration(struct evdev_device *device)
 	return 0;
 }
 
+
 static inline int
 evdev_need_mtdev(struct evdev_device *device)
 {
@@ -802,6 +825,25 @@ evdev_need_mtdev(struct evdev_device *device)
 		!libevdev_has_event_code(evdev, EV_ABS, ABS_MT_SLOT));
 }
 
+static void
+evdev_tag_device(struct evdev_device *device)
+{
+	struct udev *udev;
+	struct udev_device *udev_device = NULL;
+
+	udev = udev_new();
+	if (!udev)
+		return;
+
+	udev_device = udev_device_new_from_syspath(udev, device->syspath);
+	if (udev_device) {
+		if (device->dispatch->interface->tag_device)
+			device->dispatch->interface->tag_device(device, udev_device);
+		udev_device_unref(udev_device);
+	}
+	udev_unref(udev);
+}
+
 static int
 evdev_configure_device(struct evdev_device *device)
 {
@@ -1064,6 +1106,8 @@ evdev_device_create(struct libinput_seat *seat,
 		goto err;
 
 	list_insert(seat->devices_list.prev, &device->base.link);
+
+	evdev_tag_device(device);
 	evdev_notify_added_device(device);
 
 	return device;

src/evdev.h

@@ -48,6 +48,11 @@ enum evdev_device_seat_capability {
 	EVDEV_DEVICE_TOUCH = (1 << 2)
 };
 
+enum evdev_device_tags {
+	EVDEV_TAG_EXTERNAL_MOUSE = (1 << 0),
+	EVDEV_TAG_INTERNAL_TOUCHPAD = (1 << 1),
+};
+
 struct mt_slot {
 	int32_t seat_slot;
 	int32_t x, y;
@@ -92,6 +97,7 @@ struct evdev_device {
 
 	enum evdev_event_type pending_event;
 	enum evdev_device_seat_capability seat_caps;
+	enum evdev_device_tags tags;
 
 	int is_mt;
 
@@ -128,6 +134,10 @@ struct evdev_dispatch_interface {
 	/* A device was removed */
 	void (*device_removed)(struct evdev_device *device,
 			       struct evdev_device *removed_device);
+
+	/* Tag device with one of EVDEV_TAG */
+	void (*tag_device)(struct evdev_device *device,
+			   struct udev_device *udev_device);
 };
 
 struct evdev_dispatch {