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Display "flash down" with imx8qm

Question asked by Andrea Previtali on Jan 24, 2020
Latest reply on Feb 20, 2020 by Andrea Previtali

Hi, I'm going to describe a problem I'm encountering and I can't exactly understand which can be the cause.

 

I'm evaluating diffent board for a new project, in particoular I'm evaluating a board performing iMX8M and two boards performing iMX8QM.

 

Every board should be connected to a 15.6 dual-channel LVDS (Ampire AM-19201080D1TZQW-TA8H).

 

Using iMX8QM I noticed that when full white color should be shown on the display, the display seems to turn off with a violent flash (you can see it in the attachments). After that moment the display seems to be dead, I can only manage LED brightness thanks to a PWM.

This violent shout down is only about the LVDS, the rest of the system is correcly up, I can use the console, I can start Wi-Fi and I can start applications.

This issue occur at every level: u-boot, Kernel, file system. I don't think it is a problem about the drivers, since if I use a different color image (for example full blue 0x0000ff) the display works fine.

 

In short words, when the display has to show full white images, it seems to "shut down"

 

It happens only with this particoular dispaly (I tested 3 unit of them and I get the issue on every one of them) and if I use different compatible display I don't get this issue.

 

 

Using iMX8M I don't get this issue, but this last system mounts a LVDS bridge and the display is not magaged "directly" from the micro.

 

I tested the same application, the same color combination with iMX8QM but using HDMI output ad a HDMI-LVDS conversion board.

In this case the problem does not occur. I tested it for a very long time.

 

I'm asking here because after working on this problem with board producer we didn't find a solution (maybe in the next days we will find one).

 

I also tried to give the display a stand alone 12V but the problem persists.

 

Did you ever see something like that?

I honestly don't think it is about the board, since I reach the same problem on both of them (they are two board of two different brand).

 

Best regards,

Andrea

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