diff --git a/arch/powerpc/platforms/powermac/backlight.c b/arch/powerpc/platforms/powermac/backlight.c
index 498b042e1837567c2326c93faa404d6ffa6a4d00..c7a27eddca6d4b96f002f2c5b5a3725933849089 100644
--- a/arch/powerpc/platforms/powermac/backlight.c
+++ b/arch/powerpc/platforms/powermac/backlight.c
@@ -119,7 +119,14 @@ int pmac_backlight_set_legacy_brightness(int brightness)
 		down(&pmac_backlight->sem);
 		props = pmac_backlight->props;
 		props->brightness = brightness *
-			props->max_brightness / OLD_BACKLIGHT_MAX;
+			(props->max_brightness + 1) /
+			(OLD_BACKLIGHT_MAX + 1);
+
+		if (props->brightness > props->max_brightness)
+			props->brightness = props->max_brightness;
+		else if (props->brightness < 0)
+			props->brightness = 0;
+
 		props->update_status(pmac_backlight);
 		up(&pmac_backlight->sem);
 
@@ -140,8 +147,11 @@ int pmac_backlight_get_legacy_brightness()
 
 		down(&pmac_backlight->sem);
 		props = pmac_backlight->props;
+
 		result = props->brightness *
-			OLD_BACKLIGHT_MAX / props->max_brightness;
+			(OLD_BACKLIGHT_MAX + 1) /
+			(props->max_brightness + 1);
+
 		up(&pmac_backlight->sem);
 	}
 	mutex_unlock(&pmac_backlight_mutex);
diff --git a/drivers/video/aty/radeon_backlight.c b/drivers/video/aty/radeon_backlight.c
index 7de66b855d4e4e292d13182c40fafe0a44ceddac..1755dddf189908550b0dae24bdf8d2d498b1cc46 100644
--- a/drivers/video/aty/radeon_backlight.c
+++ b/drivers/video/aty/radeon_backlight.c
@@ -40,14 +40,14 @@ static int radeon_bl_get_level_brightness(struct radeon_bl_privdata *pdata,
 
 	mutex_unlock(&info->bl_mutex);
 
-	if (pdata->negative)
-		rlevel = MAX_RADEON_LEVEL - rlevel;
-
 	if (rlevel < 0)
 		rlevel = 0;
 	else if (rlevel > MAX_RADEON_LEVEL)
 		rlevel = MAX_RADEON_LEVEL;
 
+	if (pdata->negative)
+		rlevel = MAX_RADEON_LEVEL - rlevel;
+
 	return rlevel;
 }