IMX8QM Display port

Technical Support
1

Hi,

I am trying to use the display port with an IMX8QM on a custom board.

With the kernel from freescale 6.6.101 and the last dpfw.bin I am getting the following errors :

[drm] Started firmware!
[drm] set maximum defer retry to 5
[drm] HDP FW Version - ver 35083 verlib 20560
[drm] Only HDCP 2.2 is enabled

[ 117.275150] cdns-mhdp-imx 56268000.hdmi: [drm:cdns_mhdp_mailbox_validate_receive [cdns_mhdp_drmcore]] Hmmm spurious mailbox data maybe, cleaning out…1:2:130 vs 1:2:2
[ 117.300044] cdns-mhdp-imx 56268000.hdmi: [drm:cdns_mhdp_mailbox_validate_receive [cdns_mhdp_drmcore]] Hmmm spurious mailbox data maybe, cleaning out…1:2:130 vs 1:2:2
[ 117.324855] cdns-mhdp-imx 56268000.hdmi: [drm:cdns_mhdp_mailbox_validate_receive [cdns_mhdp_drmcore]] Hmmm spurious mailbox data maybe, cleaning out…1:2:130 vs 1:2:2
[ 117.349728] cdns-mhdp-imx 56268000.hdmi: [drm:cdns_mhdp_mailbox_validate_receive [cdns_mhdp_drmcore]] Hmmm spurious mailbox data maybe, cleaning out…1:2:130 vs 1:2:2
[ 117.367633] cdns-mhdp-imx 56268000.hdmi: [drm:cdns_mhdp_get_edid_block [cdns_mhdp_drmcore]] ERROR get block[0] edid failed: -22
[ 117.380368] [drm:cdns_dp_connector_get_modes [cdns_mhdp_drmcore]] ERROR Invalid edid
[ 117.455078] cdns-mhdp-imx 56268000.hdmi: [drm:cdns_mhdp_mailbox_validate_receive [cdns_mhdp_drmcore]] Hmmm spurious mailbox data maybe, cleaning out…1:3:6 vs 1:3:5
[ 117.477757] cdns-mhdp-imx 56268000.hdmi: [drm:cdns_mhdp_mailbox_validate_receive [cdns_mhdp_drmcore]] Hmmm spurious mailbox data maybe, cleaning out…1:3:6 vs 1:3:5
[ 117.500832] cdns-mhdp-imx 56268000.hdmi: [drm:cdns_mhdp_mailbox_validate_receive [cdns_mhdp_drmcore]] Hmmm spurious mailbox data maybe, cleaning out…1:3:6 vs 1:3:5
[ 117.522285] cdns-mhdp-imx 56268000.hdmi: [drm:cdns_mhdp_mailbox_validate_receive [cdns_mhdp_drmcore]] Hmmm spurious mailbox data maybe, cleaning out…1:3:6 vs 1:3:5
[ 117.543825] cdns-mhdp-imx 56268000.hdmi: [drm:cdns_mhdp_mailbox_validate_receive [cdns_mhdp_drmcore]] Hmmm spurious mailbox data maybe, cleaning out…1:3:6 vs 1:3:5
[ 117.565803] cdns-mhdp-imx 56268000.hdmi: [drm:cdns_mhdp_mailbox_validate_receive [cdns_mhdp_drmcore]] Hmmm spurious mailbox data maybe, cleaning out…1:3:6 vs 1:3:5

I tried to use others version of the dpfw without success.

In my dts file I use this to use the DP :

&hdmi {
status = “okay”;
compatible = “cdn,imx8qm-dp”;
firmware-name = “dpfw.bin”;
lane-mapping = <0x1b>;
hdcp-config = <0x2>;
};

The kernel error I wrote just before occur when the HPD change his level from low to high.
I see datas on the AUX pins of the DP.

With the kernel 6.6.94 and the dpfw.bin compiled from yocto the errors are identical.

Any idea ?

3

Hi, I’m the Toradex AI Assistant.

I might make mistakes or occasionally get you wrong. Our support team will step in if needed.

The DisplayPort functionality you’re asking about is not within the scope of Toradex’s supported configurations. Based on the available Toradex documentation, the Apalis iMX8 provides display signals over HDMI and LVDS interfaces(1).

For the Apalis iMX8, the supported display outputs are(1):

  • HDMI1 with device-tree node reference hdmi and DRM connector name HDMI-A-1
  • LVDS1 with device-tree node reference ldb2 and DRM connector name LVDS-1
  • Type-Specific LVDS with device-tree node reference ldb1

The documentation notes that while the hardware can provide display port signals on the HDMI connector, these interfaces have not been brought up in Linux as of yet(1).

Since you’re working with a custom board and trying to implement DisplayPort functionality that isn’t officially supported in Toradex’s BSP, I’d recommend checking these potentially useful sources:

Would you like me to provide general guidance on this topic instead, or would you prefer to explore the officially supported HDMI and LVDS display options for your Apalis iMX8?

Best regards, Toradex AI Assistant.

Did you like my answer? :+1: :-1:

If I answered your question, please tick the “Solution” checkbox.

For follow-up questions to me, please use @ToradexAI in your post.

4

Dear @78rbe,

thank you for your question and welcome to our community!
Could you tell me what specific Toradex iMX8QM module you have and what family it is from? This information helps us to better investigate your topic.

Best regards,

Collin

5

Yes of course !

I have the Apalis IMX8QM 4GB WB IT, V1.1 C

Thanks for your help