[meta-freescale] Regarding an issue faced with the PWM controller

Ayana Vincent ayana.vincent at nestgroup.net
Mon Jun 22 02:15:32 PDT 2015

Dear Sir,

This is regarding an issue faced with the PWM controller on the IMX6Q SoC.

We use PWM2 to control the back light of our LCD.

The problems is only on boot-up/wakeup (from suspend to RAM). We use echo <1..7> > /sys/class/backlight/backlight.15/brightness method to control the back light. On boot-up/wakeup, the first attempt always fails i.e. doesn't produce any output on the PWM output lines (we checked with scope) even though the SYSFS file is properly updated. In order to obtain the desired output, one should try the above command multiple times until the output is available (one could see the response from the LCD; we did also observe the pulses with scope). This inconsistency is really causing trouble to our application. Could you please shed some light on it ASAP? Is it a hardware issue? or driver issue?

Please help.


Ayana Vincent

Ayana Vincent


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