How to use pcie overlay dtbo file

Robotics & Edge Computing Jetson & Embedded Systems Jetson AGX Orin
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1

Hi, nvteam,
we are debuging the pcie c5. we find the status property of pcie_ep@141a0000 and pcie@141a0000 are overwrite by the setting in file tegra234-p3737-overlay-pcie.dts.

when I want to change the status, replace kernel_tegra234-p3701-0004-p3737-0000.dtb in directory /boot/dtb/ and tegra234-p3737-overlay-cpie.dtbo in /boot/ has no effect.

Now everytime i want to change the status. I have to reflash the whole orin with cmd sudo ./flash.sh -r jetson-agx-orin-devkit mmcblk0p1 so I wonder if there are a simple method to realize the purpose of modifying status

2

overlay dtbo is handled by bootloader/uefi. So need to update both kernel dtb and bootloader dtb.

3

ok, thankyou , I know kernel dtb is /boot/dtbkernel_tegra234-p3701-0004-p3737-0000.dtb . so which file is for bootloader dtb.

4

There is no file in rootfs that is for bootloader dtb. You need to do full flash on your host.

If you think it is wasting your time, you can also just give up using dtbo but directly put the content to your kernel dtb.

5

you mean to edit p3701.conf.common file to delete string tegra234-p3737-overlay-pcie.dtbo in OVERLAY_DTB_FILEsection , right ?

infact the most wasting time is to write our APP part. so does the flash.sh script support to flash all others except APP part. or some special cmd to realize to modifying status and donot need to flash APP part?

6

I will advise to clone the rootfs/APP partition. This is a valuable backup. Plus, if you place the clone at “Linux_for_Tegra/bootloader/system.img”, and then flash with the “-r” option on command line, it will flash everything; however, the rootfs being flashed is a copy of the original (it would be your clone). Then freshly flashes all other partitions, but in essence (other than time and disk space) is the same as flashing everything except the rootfs. It is a common story for people to lose valuable content for a lack of a backup, so cloning is a good idea anyway.

On command line (if the clone was already set up) it goes something like this (default dev kit flash):
sudo ./flash.sh jetson-agx-orin-devkit mmcblk0p1

Also, see “./flash.sh --help” from the “Linux_for_Tegra/” directory.

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