Specific HDMI screen resolution 800x480 with i.MX8M-Plus

[JoelWTK]

Hello

I'm working with iot-gate-imx8plus from compulab which integrate i.MX8M-Plus CPU and I have difficulties to use a specific screen with resolution 800x480 over HDMI interface.

From the reference manual of the processor, I have read the following:

HDMI 2.0a Tx supporting one display

Resolutions of: 740x480p60, 720x480p60, 1280x720p60, 1920x1080p60, 1920x1080p120, 3840x2160p30

So the resolution I want is not listed. Is it possible to achieve such resolution ?

I started working on the topic by setting a custom edid file, playing with video= kernel parameter to force 800x480 resolution, but still not working. The best I succeed to do is to have HDMI connected and weston complaining because the the HDMI interface has no modes available

Thanks for feedbacks about this topic (I see it has been discussed many times but no clear answer is done).

Joel

[JoelWTK · Accepted solution]

Hello,

Problem was HDMY PHY clock values available in linux-imx. See https://community.nxp.com/t5/i-MX-Processors/Specific-HDMI-screen-resolution-quot-hdmi-phy-quot-cloc....

Joel

[JoelWTK]

Hello @Bio_TICFSL 

Thanks for the reply. Do you know a tutorial somewhere for that ? Looks not so trivial probably ?

Joel

[Bio_TICFSL]

Sorry no, the only information about the hdmi driver is on the Linux reference manual

https://www.nxp.com/docs/en/reference-manual/IMX_REFERENCE_MANUAL.pdf

Regards

[Bio_TICFSL]

Hello,

The resolution is not supported by the driver, in this case you will have to add it and add it to your dtb.

Regards