strange blink pixels on lvds screen

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strange blink pixels on lvds screen

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cxh
Contributor I

Hi,

We found there's strange blink pixels on lvds screen sometimes.

We try to write the fb0/blank device to make the screen blank and restore it again,

and then found the blink pixels may disappears or appears randomly.

    root@sabresd_6dq:/ # echo 1 > /sys/class/graphics/fb0/blank                   

    root@sabresd_6dq:/ # echo 0 > /sys/class/graphics/fb0/blank

Here's the boot command

    root@sabresd_6dq:/ # cat /proc/cmdline                                       

    console=ttymxc0,115200 androidboot.console=ttymxc0 androidboot.hardware=freescale init=/init video=mxcfb0:dev=ldb,1280x800M@60,if=RGB666,bpp=32 video=mxcfb1:dev=hdmi,1920x1080M@60,if=RGB24,bpp=32 video=mxcfb2:off fbmem=14M,28M vmalloc=512M ldb=dul1

This is screen with strange blink pixel --

IMG_20150602_173819.jpg

This is good screen --

IMG_20150602_174040.jpg

Thank you!

Any suggestion will be appreciated!

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igorpadykov
NXP Employee
NXP Employee

Hi c

issue may be caused by noise (one can decrease cable length or

LCD frame rate) or incorrect memory settings : for example

memory region overlapped with other reserved memory, such as GPU memory etc.

Also it is recommended to apply all latest fixes and updates for BSP,

as was on

https://community.freescale.com/message/320101#320101

Best regards

igor

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cxh
Contributor I

Thank you, Igor!

There's no download link in this post

Re: Problem configuring 2GB DDR3 on i.MX6 Android BSP?

And more, we use IMX6_JB43_111, gpu bugs in ICS should be fixed in this version, I think.

Today we have new progress --

If we change ldb=dul1 to ldb=sep0 in boot commands, we can not find the blink pixels now.

It seems not like a problem of noise or cable.

( But if using ldb=sep0, hdmi will be disabled, so we still have to use ldb=dul1 )

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igorpadykov
NXP Employee
NXP Employee

Hi c

one can look at attached document for JB43_111 patches.

~igor

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cxh
Contributor I

Hi, Igor,

Checked the patched files one by one manually, and confirmed all patches have been applied.

The problem is not fixed.

We're think about why to change ldb=dul1 to ldb=sep0 will fix this problem ...

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