e backlight - restructure to have real per screen backlight

now it really does look for the right way to control per screen and
only use the new e_system back-end to query/list devices etc. ...

this now opens the door to adding ddc support to e_system then using
it from e_backlight.

i can't test this... yet - but this means in theory the backlight
gadget will control the backlight of the screen it is on...

src/bin/e_comp_x.c

@@ -75,7 +75,6 @@ static Ecore_X_Randr_Screen_Size screen_size = { -1, -1 };
 static int screen_size_index = -1;
 
 static Ecore_X_Atom backlight_atom = 0;
-extern double e_bl_val;
 
 static Ecore_Timer *mouse_in_fix_check_timer = NULL;
 
@@ -5293,17 +5292,8 @@ _e_comp_x_screensaver_notify_cb(void *data EINA_UNUSED, int type EINA_UNUSED, Ec
 static Eina_Bool
 _e_comp_x_backlight_notify_cb(void *data EINA_UNUSED, int t EINA_UNUSED, Ecore_X_Event_Randr_Output_Property_Notify *ev)
 {
-   double x_bl;
-
    if (ev->property != backlight_atom) return ECORE_CALLBACK_RENEW;
-   x_bl = ecore_x_randr_output_backlight_level_get(0, ev->output);
-
-   if (x_bl >= 0.0)
-     {
-        if (fabs(e_bl_val - x_bl) < DBL_EPSILON)
-          ecore_event_add(E_EVENT_BACKLIGHT_CHANGE, NULL, NULL, NULL);;
-        e_bl_val = x_bl;
-     }
+   e_backlight_update();
    return ECORE_CALLBACK_RENEW;
 }
 

src/bin/e_config.h

@@ -372,7 +372,6 @@ struct _E_Config
       double        battery_timer; // GUI
       const char   *sysdev; // GUI
       unsigned char idle_dim; // GUI
-      E_Backlight_Mode mode; /* not saved, display-only */
    } backlight;
 
    struct

src/bin/e_zone.h

@@ -62,6 +62,8 @@ struct _E_Zone
    /* formerly E_Comp_Zone */
    Evas_Object *base;
    Evas_Object *over;
+
+   E_Backlight_Mode bl_mode;
    double       bl;
    Eina_Bool    bloff;