Imx6q backlight

[senli]

Hi all:

    the BSP I used is linux 3.14.52.

    I used pwm backlight ,and the backlight driver is work normally .

    But now ,I found a question about backlight . That is when process "init" called "S01xserver-nodm",I can find the backlight should be off ,then on ,then off ,on again .

     I want to know how to fix it ?

     thanks

[weidong_sun]

Hello Sen,

     See following advice for you, pleae!

(1) Measuring wave form of PWM

Check if PWM wave form is normal.

(2) Checking LED driver circuit

If PWM wave form is ok, please check if LED driver chip's enable PIN can work normally.

(3) Checking driving capbility of  LED driver chip.

I mean if drving current provided by LED driver chip is enough.

This is an example, hope it is helpful for you:

Best Regards,

Weidong

[senli]

Hello Weidong:

         Thanks for your reply!

          The wave of PWM is normally ,and the hardware circuit also is normally .

          And I add debug message in function " pwm_backlight_update_status" which is in pwm_bl.c.

          And I found some another application ,called it ,and set brightness=0 and then set brightness=6 and set brightness=0 again ,

          finnally set brightness=6.

          But I do not know which application set it .

          Can you help me ?