[gnome-settings-daemon] backlight: Fix return value of async brightness changes

[Benjamin Berg <bberg src gnome org>]

commit cd4418653f317fcd2d6a6d69f14fdc2e005e092c
Author: Jonas Dreßler <verdre v0yd nl>
Date:   Thu Dec 12 12:09:14 2019 +0100

    backlight: Fix return value of async brightness changes
    
    With cd051e6c7ccfb7e7b0ec440409c559b2e51284e8 we added another method
    for setting the display brightness, it was forgotten there to convert
    the actual brightness value to a percentage when setting the GTask
    return value.
    
    Since this return value is used to display the brightness OSD in
    gsd-media-keys-manager, we ended up with values above 100% shown in the
    brightness OSD. Fix that by adjusting the return value to be a
    percentage.

 plugins/power/gsd-backlight.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
---
diff --git a/plugins/power/gsd-backlight.c b/plugins/power/gsd-backlight.c
index f4d60306..9f406c99 100644
--- a/plugins/power/gsd-backlight.c
+++ b/plugins/power/gsd-backlight.c
@@ -469,6 +469,7 @@ gsd_backlight_set_brightness_val_async (GsdBacklight *backlight,
         GError *error = NULL;
         GTask *task = NULL;
         GnomeRROutput *output;
+        gint percent;
 
         value = MIN(backlight->brightness_max, value);
         value = MAX(backlight->brightness_min, value);
@@ -491,7 +492,11 @@ gsd_backlight_set_brightness_val_async (GsdBacklight *backlight,
                                            G_DBUS_CALL_FLAGS_NONE,
                                            -1, NULL,
                                            NULL, NULL);
-                        g_task_return_int (task, backlight->brightness_target);
+
+                        percent = ABS_TO_PERCENTAGE (backlight->brightness_min,
+                                                     backlight->brightness_max,
+                                                     backlight->brightness_target);
+                        g_task_return_int (task, percent);
                 } else {
                         task_data = g_new0 (BacklightHelperData, 1);
                         task_data->value = backlight->brightness_target;