In order to correct this situation, a recommended solution is to change the PWM period used for controlling the backlight. In the Freescale BSP the can be achieved for the SMD with the following patch:
diff --git a/arch/arm/mach-mx5/mx53_smd.c b/arch/arm/mach-mx5/mx53_smd.c
index 46188fd..f4bbe5a 100644
--- a/arch/arm/mach-mx5/mx53_smd.c
+++ b/arch/arm/mach-mx5/mx53_smd.c
@@ -499,7 +499,7 @@ static struct platform_pwm_backlight_data mxc_pwm_backlight_data = {
.pwm_id = 1,
.max_brightness = 255,
.dft_brightness = 128,
- .pwm_period_ns = 50000,
+ .pwm_period_ns = 45454,
};