imx8qm no hdmi signal

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imx8qm no hdmi signal

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Ahelion
Contributor IV

Hello all,

I have followed the quick-stard guide, attached the hdmi to both the hdmi port and the LVDS thing, it came with some converter card. I have no hdmi output, nothing is visible on the screen:

I found this thread, but did not understand it:

https://community.nxp.com/t5/i-MX-Processors/i-MX-8QuadMax-LVDS-HDMI-output-no-signal-from-J2-J3/m-p...

can anybody help?

BR, Mircea

 

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Ahelion
Contributor IV

Thank you!

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Chavira
NXP TechSupport
NXP TechSupport

Hi @Ahelion!
Thank you for contacting NXP Support!

You have to use the DTB for native HDMI, for LVDS you'll need to change it

fsl-imx8qm-mek-hdmi.dtb -> fsl-imx8qm-mek.dtb, you'll find this file in the FAT partition if you flashed the .wic

 

To do this you need to do the following:

Step 1: Power on the board and press any key to stop the boot process at U-boot.

Step 2: Type the following command to modify the default DTB

=>setenv fdt_file fsl-imx8qm-mek.dtb

Step 3: Save the environment variable by typing the command below

=> saveenv

Step 4: Boot the Linux Kernel by resetting the board or typing the command below:

=> boot

Please note that based on which DTB file is chosen then correct number of IMX-LVDS-HDMI and IMX-MIPI-

HDMI cards has to be connected for the displays to come up.

 

From L4.19.35_1.1.0 i.MX_Linux_Release_Notes.pdf:

fsl-imx8qm-mek.dtb: Supports the LVDS-HDMI or MIPI-DSI-HDMI display with the LVDS-HDMI or MIPI-DSI-HDMI converts. The detection is on-the-fly by using the device-tree overlay technology.

fsl-imx8qm-mek-hdmi.dtb: Supports native HDMI TX interface on the CPU board.

fsl-imx8qm-mek-jdi-wuxga-lvds1-panel.dtb: Supports the dual channel LVDS panel, connecting the two mini-SAS ports with the LVDS1 CH0 and LVDS1 CH1.

 

If you want to use the native HDMI to run a quick test you'll need to connect your HDMI cable to the HDMI TX (J6).

Please check the Linux Release notes:

https://www.nxp.com/docs/en/release-note/IMX_LINUX_RELEASE_NOTES.pdf

Best Regards!

Chavira