I tried to be enable hdmi from what you shared.
Only single point is changed in kernel source code file as below:
tegra234-p3701-0000-p3737-0000.dts => tegra234-p3701-0004-p3737-0000.dts
Anyway, It doesn’t works for enabling HDMI.
Could you check the booting log? jp5.0.2_boot_log.txt (90.6 KB)
And you can see what system message be gotten when the hdmi cable has reconnected. dmesg.txt (126.0 KB)
The HDMI Enable Pin is GPIO(A, 3),
It is DP Enable Pin with default device tree.
The HDMI design guide looks HDMI Enable pin woks to input enable.
But our design is close to DP reference design than HDMI reference design.
So, our hardware engineer told me, It can display out if the HDMI Enabler Pin is High.
And GPIO(A, 3) is enable from fixed regulator setting as a default.
But it doesn’t work for display out.