pad: default a pad group to mode 0 if all LEDs are off

Since our API doesn't accomodate for "dunno" we need to pick a mode that
we are actually in. This happens on the Intuos Pro 2 (PTH-660) which has
all LEDs on brightness zero, resulting in a failure to set up the modes
and we're left without a mode button.

Fix it by just picking zero as the default mode until specified
otherwise.

Part-of: <https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/1069>

diff --git a/src/evdev-tablet-pad-leds.c b/src/evdev-tablet-pad-leds.c
index ba7b9e6d99a55de8ce799d5265b7f10284a09961..f1c70f82d08f7f3798fb677583a1faa5bb28cc3a 100644 (file)
--- a/src/evdev-tablet-pad-leds.c
+++ b/src/evdev-tablet-pad-leds.c
@@ -83,7 +83,9 @@ pad_led_group_get_mode(struct pad_led_group *group)
                        return led->mode_idx;
        }
 
-       return -EINVAL;
+       /* Wacom PTH-660 doesn't light up any LEDs
+        * until the button is pressed, so let's assume mode 0 */
+       return 0;
 }
 
 static inline void