Custom HDMI Resolution Configuration Issue on i.MX8M Plus

[SanthoshRajavel]

We are configuring a MAX96751 serializer for a resolution of 1600×480. We have generated a custom EDID and configured the serializer accordingly. When connected to a laptop/PC, the system correctly detects and supports the 1600×480 resolution.

However, on our i.MX8M Plus EVK, the HDMI output only defaults to 800×600, and the custom resolution is not being applied.

We have already:

• Generated and applied a custom EDID
• Verified the resolution works on other systems (PC/laptop)
• Attempted manual resolution configuration

Could you please confirm:

1. Whether the i.MX8M Plus HDMI interface supports custom resolutions and timings?
2. The correct procedure to configure a custom HDMI resolution (e.g., via EDID, device tree, or DRM settings)?
3. Any additional steps required to force the system to use the custom mode?
   
   My EDID
   
   root@imx8mp-lpddr4-evk:~# cat /sys/class/drm/card1-HDMI-A-1/edid | hexdump -C
   00000000 00 ff ff ff ff ff ff 00 04 89 01 00 00 00 00 00 |................|
   00000010 01 21 01 04 a5 46 27 78 3a 76 45 ae 51 33 ba 26 |.!...F'x:vE.Q3.&|
   00000020 0d 50 54 01 00 00 01 01 01 01 01 01 01 01 01 01 |.PT.............|
   00000030 01 01 01 01 01 01 40 17 40 80 61 e0 14 10 58 90 |......@.@.a...X.|
   00000040 37 00 ba 89 21 00 00 1e 00 00 00 ff 00 47 4d 53 |7...!........GMS|
   00000050 4c 30 30 31 0a 20 20 20 20 20 00 00 00 fc 00 47 |L001. .....G|
   00000060 4d 53 4c 0a 20 20 20 20 20 20 20 20 00 00 00 fd |MSL. ....|
   00000070 00 18 4b 1e b4 6c 01 0a 20 20 20 20 20 20 00 d2 |..K..l.. ..|
   00000080
   
   Board : IMX8MP-Lpddr4
   Linux : 6.6
   
   

[joanxie]

what pixel clock do you need for resolution 1600×480? pls check your log and offer the correct pixel clock you need from imx8mp hdmi output