HDMI Display Flickering/Shaking on Apalis iMX8

Technical Support
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I’m facing an issue with HDMI output on my Apalis iMX8. Parts of the screen are shaking or flickering, almost like a signal instability issue. It could be a timing mismatch, pixel clock problem, or signal integrity issue.

Has anyone encountered this? Any suggestions on adjusting HDMI timing parameters, EDID fixes, or driver changes?

root@apalis-imx8-15310003:~# dmesg | grep hdmi
[    0.460809] platform 56268000.hdmi: Fixing up cyclic dependency with 56180000.dpu
[    7.333378] cdns-mhdp-imx 56268000.hdmi: lane-mapping 0x93
[    7.358659] imx-drm display-subsystem: bound 56268000.hdmi (ops cdns_mhdp_imx_ops [cdns_mhdp_imx])
[    7.431572] input: imx-audio-hdmi-tx HDMI Jack as /devices/platform/sound-hdmi/sound/card1/input4
[    7.432602] cdns-mhdp-imx 56268000.hdmi: 0,ff,ff,ff,ff,ff,ff,0
[   11.931849] cdns-mhdp-imx 56268000.hdmi: 0,ff,ff,ff,ff,ff,ff,0
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Hi, I’m the Toradex AI Assistant. The Toradex Support team will follow up with you shortly!

Did you like my answer?

:+1: :-1:

Hello there!

I’m sorry to hear about the HDMI display flickering and shaking issues you’re experiencing with your Apalis iMX8. Let’s explore some steps you can take to troubleshoot and potentially resolve this problem:

  1. Check Hardware Connections: Ensure that all HDMI cables and connections are secure and undamaged, as a loose or faulty cable can lead to signal instability.

  2. EDID and Display Modes: Verify that the correct EDID (Extended Display Identification Data) is being used. If necessary, you can inject a binary EDID blob by placing it in /lib/firmware/edid/ and setting the drm.edid_firmware parameter on the kernel command line. This helps ensure the display operates in a supported mode.

  3. Adjust HDMI Timing Parameters: You might need to adjust the HDMI timing parameters in the device tree. This involves specifying the correct display timings for your monitor. The panel-lvds driver allows you to specify detailed timings in the device tree, which can be crucial for resolving timing mismatches.

  4. Use Diagnostic Tools: Utilize tools like modetest from the libdrm package to print information on the current DRM state and test different display modes. This can help identify if the issue is related to a specific mode or timing setting.

  5. Kernel and Driver Updates: Ensure you are using the latest BSP (Board Support Package) and kernel version for your Apalis iMX8. Updates may include fixes for known issues related to HDMI output.

  6. Weston Configuration: If you are using Weston as your compositor, check the configuration in /etc/xdg/weston/weston.ini to ensure the correct display mode is set. Weston can override kernel settings, so it’s important to verify its configuration.

By following these steps, you should be able to diagnose and potentially resolve the HDMI flickering issue on your Apalis iMX8. If the problem persists, further investigation into the specific hardware and software setup may be necessary.

Best regards,
Toradex AI Assistant

Please, also check if these links can help you solve your problem:

Imx8qm HDMI blanking time adjustments.

3

Hi @rania !

I don’t recall getting such issue on Apalis iMX8QM. Also my colleagues are strange to such issue.

Could you please share more details about your setup?

  1. Please share the tdx-info output.
  2. Which carrier board are you using? Please share its full name and version
  3. Do you see the flickering when using Toradex’s Reference Multimedia Image from the latest BSP 7 quarterly release?
  4. Does the flickering occur on different HDMI displays/monitors?
  5. Have tried different HDMI cables?
  6. Are you using the recommended heatsink with your Apalis iMX8QM?
  7. Does the flickering always occur or it just shows up in specific moments?
  8. Could you please share a video of the flickering?
  9. In which resolution (or resolutions) does the flickering occur?

Best regards,