udev: check wacom devices for a paired product id

The newer Wacom Cintiqs have touch devices with a different PID than the pen
device. Use the new libwacom_get_paired_device call where available to pair
the two devices and give them the same device group.

This isn't that important just yet, so no need to force users to update to a
new libwacom version.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Tested-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>

configure.ac

@@ -208,7 +208,26 @@ AC_ARG_ENABLE(libwacom,
 if test "x$use_libwacom" = "xyes"; then
 	PKG_CHECK_MODULES(LIBWACOM, [libwacom >= 0.12], [HAVE_LIBWACOM="yes"])
 	AC_DEFINE(HAVE_LIBWACOM, 1, [Build with libwacom])
+
+	OLD_LIBS=$LIBS
+	OLD_CFLAGS=$CFLAGS
+	LIBS="$LIBS $LIBWACOM_LIBS"
+	CFLAGS="$CFLAGS $LIBWACOM_CFLAGS"
+	AC_MSG_CHECKING([if libwacom_get_paired_device is available])
+	AC_LINK_IFELSE(
+		       [AC_LANG_PROGRAM([[#include <libwacom/libwacom.h>]],
+					[[libwacom_get_paired_device(NULL)]])],
+		       [AC_MSG_RESULT([yes])
+			AC_DEFINE(HAVE_LIBWACOM_GET_PAIRED_DEVICE, [1],
+				  [libwacom_get_paired_device() is available])
+		        [libwacom_have_get_paired_device=yes]],
+		       [AC_MSG_RESULT([no])
+		        [libwacom_have_get_paired_device=no]])
+	LIBS=$OLD_LIBS
+	CFLAGS=$OLD_CFLAGS
 fi
+AM_CONDITIONAL(HAVE_LIBWACOM_GET_PAIRED_DEVICE,
+	       [test "x$libwacom_have_get_paired_device" == "xyes"])
 
 AM_CONDITIONAL(HAVE_VALGRIND, [test "x$VALGRIND" != "x"])
 AM_CONDITIONAL(BUILD_TESTS, [test "x$build_tests" = "xyes"])

udev/Makefile.am

@@ -7,9 +7,16 @@ litest_rules = 80-libinput-device-groups-litest.rules \
 noinst_SCRIPTS = $(litest_rules)
 
 libinput_device_group_SOURCES = libinput-device-group.c
-libinput_device_group_CFLAGS = $(LIBUDEV_CFLAGS) $(GCC_CFLAGS)
+libinput_device_group_CFLAGS = -I$(top_srcdir)/src \
+			       $(LIBUDEV_CFLAGS) \
+			       $(GCC_CFLAGS)
 libinput_device_group_LDADD = $(LIBUDEV_LIBS)
 
+if HAVE_LIBWACOM_GET_PAIRED_DEVICE
+libinput_device_group_CFLAGS += $(LIBWACOM_CFLAGS)
+libinput_device_group_LDADD += $(LIBWACOM_LIBS)
+endif
+
 libinput_model_quirks_SOURCES = libinput-model-quirks.c
 libinput_model_quirks_CFLAGS = \
 			       -I$(top_srcdir)/src \

udev/libinput-device-group.c

@@ -21,11 +21,49 @@
  * DEALINGS IN THE SOFTWARE.
  */
 
+#include "config.h"
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <libudev.h>
 
+#include "libinput-util.h"
+
+#if HAVE_LIBWACOM_GET_PAIRED_DEVICE
+#include <libwacom/libwacom.h>
+
+static void
+wacom_handle_paired(struct udev_device *device,
+		    int *vendor_id,
+		    int *product_id)
+{
+	WacomDeviceDatabase *db = NULL;
+	WacomDevice *tablet = NULL;
+	const WacomMatch *paired;
+
+	db = libwacom_database_new();
+	if (!db)
+		goto out;
+
+	tablet = libwacom_new_from_usbid(db, *vendor_id, *product_id, NULL);
+	if (!tablet)
+		goto out;
+	paired = libwacom_get_paired_device(tablet);
+	if (!paired)
+		goto out;
+
+	*vendor_id = libwacom_match_get_vendor_id(paired);
+	*product_id = libwacom_match_get_product_id(paired);
+
+out:
+	if (tablet)
+		libwacom_destroy(tablet);
+	if (db)
+		libwacom_database_destroy(db);
+}
+#endif
+
 int main(int argc, char **argv)
 {
 	int rc = 1;
@@ -34,6 +72,7 @@ int main(int argc, char **argv)
 	const char *syspath,
 	           *phys = NULL;
 	const char *product;
+	int bustype, vendor_id, product_id, version;
 	char group[1024];
 	char *str;
 
@@ -73,8 +112,29 @@ int main(int argc, char **argv)
 	   on that*/
 	product = udev_device_get_property_value(device, "PRODUCT");
 	if (!product)
-		product = "";
-	snprintf(group, sizeof(group), "%s:%s", product, phys);
+		product = "00/00/00/00";
+
+	if (sscanf(product,
+		   "%x/%x/%x/%x",
+		   &bustype,
+		   &vendor_id,
+		   &product_id,
+		   &version) != 4) {
+		snprintf(group, sizeof(group), "%s:%s", product, phys);
+	} else {
+#if HAVE_LIBWACOM_GET_PAIRED_DEVICE
+	    if (vendor_id == VENDOR_ID_WACOM)
+		    wacom_handle_paired(device, &vendor_id, &product_id);
+#endif
+	    snprintf(group,
+		     sizeof(group),
+		     "%x/%x/%x/%x:%s",
+		     bustype,
+		     vendor_id,
+		     product_id,
+		     version,
+		     phys);
+	}
 
 	str = strstr(group, "/input");
 	if (str)