[gnome-settings-daemon] wacom: check for the new HID unified kernel ABI when setting LEDs

[Bastien Nocera <hadess src gnome org>]

commit 1c6627f5b51cb30fecda0e57e6d8d77bccb5171c
Author: Benjamin Tissoires <benjamin tissoires redhat com>
Date:   Tue Aug 12 10:49:32 2014 -0400

    wacom: check for the new HID unified kernel ABI when setting LEDs
    
    In kernel v3.17 and later, the Wacom LED sysfs attribute is located under
    the HID node, not the USB one. This new path is now common between USB
    and Bluetooth, so no special handling is required for Bluetooth now.
    
    Check for its availability first, and then fall back on the old path.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=734455

 plugins/wacom/gsd-wacom-led-helper.c |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)
---
diff --git a/plugins/wacom/gsd-wacom-led-helper.c b/plugins/wacom/gsd-wacom-led-helper.c
index a00dfdf..2f558ee 100644
--- a/plugins/wacom/gsd-wacom-led-helper.c
+++ b/plugins/wacom/gsd-wacom-led-helper.c
@@ -82,6 +82,21 @@ get_led_sys_path (GUdevClient *client,
        GList *element;
        const char *dev_hid_uniq;
 
+       /* check for new unified hid implementation first */
+       parent = g_udev_device_get_parent_with_subsystem (device, "hid", NULL);
+       if (parent) {
+               status = g_strdup_printf ("status_led%d_select", group_num);
+               filename = g_build_filename (g_udev_device_get_sysfs_path (parent), "wacom_led", status, 
NULL);
+               g_free (status);
+               g_object_unref (parent);
+               if(g_file_test (filename, G_FILE_TEST_EXISTS)) {
+                       *write_value = led_num;
+                       return filename;
+               }
+               g_clear_pointer (&filename, g_free);
+       }
+
+       /* old kernel */
        if (usb) {
                parent = g_udev_device_get_parent_with_subsystem (device, "usb", "usb_interface");
                if (!parent)