Hi，
I read the document to know diable console over uart.
https://docs.nvidia.com/jetson/archives/r35.3.1/DeveloperGuide/text/SD/Kernel/BootTimeOptimzation.html?highlight=time#disable-console-printing-over-uart
My question is that:
Can I turn on the console-printing-over-uart after the machine power on?
Thanks！
Hi zt_minto,
Are you using the devkit or custom board?
What’s your Jetpack version in use?
No, the kernel cmdline is read during kernel loaded.
To optimize the boot time, I would suggest enabling the timestamp in serial console log first.
Hi Kevin,
It’s a custom board. The Jackpack version is Jetpack 5.1.1
Attached the com log.
From press power on button, to boot logo shows up, the time costs about 14s.
[18:12:39.708] [18:12:40.383] Jetson UEFI firmware (version 3.1-32827747 built on 2023-03-19T14:56:32+00:00)
[18:12:40.383] ESC to enter Setup.
[18:12:40.383] F11 to enter Boot Manager Menu.
[18:12:40.391] Enter to continue boot.
From boot logo to system user log in, the time costs about 37s.
[18:13:03.515] Ubuntu 20.04.5 LTS tegra-ubuntu ttyTCU0
[18:13:03.519]
[18:13:03.519] tegra-ubuntu login:
Please suggest me how to optimize the power on time. Thanks.
Here aare some hints:
Regarding your first posting: The key is not to disable the serial console itself (this will basically disconnect the pins from the uart but doesn’t reduce the time) but to disable the kernel and module printk calls itself.
I guess you can do very little to the bootloader.
Thanks fchkjwlsq!
Good materials.
As for my first posting. Yes, I mean the printf calls itself.
You could update UEFI binary with r35.3.1-updates branch in Build without docker · NVIDIA/edk2-nvidia Wiki (github.com), and you could get 4s improvement in boot time.
and you could also configure the autoboot time from 5s to 0s through UEFI menu or the configuration file in UEFI source.
Thanks Kevin.
For the build without docker, I met error while configure edkrepo.
For the method of reducing autoboot time, is there a reference guide?
Are you using standalone Ubuntu 18.04 or 20.04 as your host PC?
Have you referred to each steps in instruction to configure edkrepo?
Please refer to the UEFI source
https://github.com/NVIDIA/edk2-nvidia/blob/main/Platform/NVIDIA/NVIDIA.common.dsc.inc#L676
gEfiMdePkgTokenSpaceGuid.PcdPlatformBootTimeOut|L"Timeout"|gEfiGlobalVariableGuid|0x0|5
This 5 seconds is for user to interrupt and enter UEFI menu. It could be customized setting to 0 to disable.
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