diff --git a/arch/arm/mach-rk30/board-rk30-ds975.c b/arch/arm/mach-rk30/board-rk30-ds975.c
index a516a67d7b9b..ca328e49cb1f 100755
--- a/arch/arm/mach-rk30/board-rk30-ds975.c
+++ b/arch/arm/mach-rk30/board-rk30-ds975.c
@@ -821,6 +821,7 @@ static int rk29_backlight_pwm_resume(void)
 }
 
 static struct rk29_bl_info rk29_bl_info = {
+        .pre_div = 30*1000,
 	.pwm_id = PWM_ID,
 	.bl_ref = PWM_EFFECT_VALUE,
 	.io_init = rk29_backlight_io_init,