Disable HDMI output during UEFI

[amir.s]

Hi,

I am using SDK 5.1.2 L4T 35.4.1 on Evm and on custom hardware,
I am also able to build and replace/update UEFI image succesfully.
I have used the r35.4.1-updates combo for UEFI image build,

Please I have 2 questions

1. Do i only have to replace uefi_jetson.bin or also replace BOOTAA64.efi
2. How can i disable the HDMI output of UEFI compleatly, I want a black screen until linux takes over, is this possible ?

Thank You

[KevinFFF]

Hi amir.s,

@amir.s

Do i only have to replace uefi_jetson.bin or also replace BOOTAA64.efi

It depends on you use case, you could replace both and perform full flash to make sure your modification applied correctly.

@amir.s

How can i disable the HDMI output of UEFI compleatly, I want a black screen until linux takes over, is this possible ?

Do you mean that you want to disable any display output in UEFI?

[amir.s]

Hi KevinFFF,
1.
Ok I will replace both BOOT & jetson_uefi

Acctually i Managed to disable UEFI on HDMI by remarking the T194 Display Driver in UEFI code, Like so:
Remarked Display Driver in: Platform/NVIDIA/Jetson/Jetson.dsc.inc|
#Silicon/NVIDIA/Tegra/T194/Drivers/T194GraphicsOutputDxe/T194GraphicsOutputDxe.inf {

#BaseMemoryLib|MdePkg/Library/BaseMemoryLib/BaseMemoryLib.inf
#}

Also Remarked Driver Inf in file :Platform/NVIDIA/Jetson/Jetson.fdf.inc|

#INF Silicon/NVIDIA/Tegra/T194/Drivers/T194GraphicsOutputDxe/T194GraphicsOutputDxe.inf

These changes made the HDMI during UEFI boot to be compleatly disabled, kernel boot succesfully and takes over the HDMI ok.
if you think what I did may cause issues please let me know.

Thanks
Amir

[KevinFFF]

It should be okay with those changed in configuration file if you don’t need display functions in UEFI.