compositor: Make backlight_current int32_t to avoid unsigned overflow

Backlight brightness was wrapping around when decrementing from 0.

diff --git a/src/compositor.h b/src/compositor.h
index 06476cc..a4292d2 100644 (file)
--- a/src/compositor.h
+++ b/src/compositor.h
@@ -197,7 +197,7 @@ struct weston_output {
        int (*switch_mode)(struct weston_output *output, struct weston_mode *mode);
 
        /* backlight values are on 0-255 range, where higher is brighter */
-       uint32_t backlight_current;
+       int32_t backlight_current;
        void (*set_backlight)(struct weston_output *output, uint32_t value);
        void (*set_dpms)(struct weston_output *output, enum dpms_enum level);