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iMX6DL : LVDS display a horizontal noise with Sabre Board

Question asked by koichi sakagami on Jan 21, 2016
Latest reply on Jan 28, 2016 by Qiang Li - Mpu Se

Dear community,

 

We are facing a problem.

 

We prepared the software development environment using the freescale BSP.
We made the Linux image with default settings.


We displayed the test image ,and
repeat the LVDS output switching(ON/OFF),then
a noise occurs horizontally on the LCD display.

 

Why will such a phenomenon occur on i.MX6 ?

 

The procedure to let a phenomenon reappear with a Sabre board are as follows.

 

[Reproduction Sequence]
   Step1 : Change the U-boot environment 
   Step2 : pour  test2.rgb into fb0 in succession 
   Step3 : ON/OFF repeats the fb0 output switch by “blank command” 

Then, a noise occurs horizontally on the LCD display.


The phenomenon occurs with porbability of 1/10 .

 

 

[System Configurations]
  BSP : L3.0.35_4.1.0
  Board : MCIMX6DL-SDP
              It seems that the board revision is related.
                       SCH-27417 REV C4 <-- The phenomenon occurs.
                       SCH-27417 Rec C2  <-- The phenomenon does not occur.

 

[Step1] Change the U-boot environment 

    setenv loadaddr 0x10800000
    setenv bootargs_base 'setenv bootargs console=ttymxc0,115200'
    setenv bootargs_mmc 'setenv bootargs ${bootargs} root=/dev/mmcblk1p1 rootwait rw video=mxcfb0:dev=ldb,LDB-XGA,if=RGB666,ldb=dul1'
    setenv bootcmd_mmc 'run bootargs_base bootargs_mmc;mmc dev 2;mmc read ${loadaddr} 0x800 0x2000;bootm'
    setenv bootcmd 'run bootcmd_mmc'
    saveenv

 

[Step2] pour  test2.rgb into fb0 in succession 

test2.sh is as follows.

 

  #!/bin/sh  
  echo "test2.rgb"  
  while [ "1" ]  
  do  
          cat test2.rgb > /dev/fb0 
  done

 

 

Test2.rgb format is

      [ FF FF FF FF 00 00 00 FF] ……  repeat

 

I attach the input data file (test2.rgb).

 

[Step 3] ON/OFF repeats the fb0 output switch by “blank command” 

 

sh test2.sh &  
echo 1 > /sys/class/graphics/fb0/blank  
echo 0 > /sys/class/graphics/fb0/blank  
[Enter]  
[Enter]  
.......... repeat ............

 


Best Regards,
Koichi Sakagami

Original Attachment has been moved to: test2.sh

Original Attachment has been moved to: test2.zip

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