Two DP setting

Autonomous Machines Jetson & Embedded Systems Jetson Xavier NX
1

Hi i’m trying to multi display Deepstream DP AND DP

now i’m using dev kit, so i verifying my pipeline output to the two monitor( HDMI & DP)
but i will insert the module to the other carrier board
it support 2 DP port
but i’m not sure it will work

before the this question i found
i should change the device tree syntax
but i never do that before

can you tell me step by step?
or can you give me a reference ?

i heard i should change
sor / nvdisplay

i need change thd dts/dtb only?
or compile something?

3

Hi,

Do you have software engineer who is familiar with linux device tree structure? It would be better to ask them to do this work for you.

4

Thanks for reply

5

Hi,

In brief, the compile of dtb could be done by this instructions.

https://docs.nvidia.com/jetson/l4t/index.html#page/Tegra%2520Linux%2520Driver%2520Package%2520Development%2520Guide%2Fkernel_custom.html%23wwpID0E0FD0HA

And you can copy the setting from existing DP port to overwrite the config of existing HDMI port.

6

Hi.
Thanks for instruction @WayneWWW

i set the sor1 HDIM disable and sor1 DP okay
after then dts covert to dtb file

and finally i flash to the emmc!

now
can i check the setting is done?( with any log or signal check)
i don’t have my 2DP hw yet
now my dev.kit HDMI port does not working (no OUTPUT)

now i use xrandr
screen0 :~~
DP-0 connected~~~

but before i change the dtb file
it has
screen0 :~~
HDIM-0 connected~~
DP-0 disconnected~~
when i use only HDMI port

And
i wonder if i want to change the dtb should i reflash all the system on jetson?

sudo ./flash.sh jetson-xavier-nx-devkit-emmc mmcblk0p1

can i change only dtb related display??

7

  1. You can check kernel log by command dmesg

  2. You can flash dtb only by

sudo ./flash.sh -r -k kernel-dtb …

8

  1. what should i check with dmesg?

  2. sudo ./flash.sh -r -k kernel-dtb
    is done ? you said “…” what it means
    and my host pc has kernel folder not kernel-dtb
    should i use
    sudo ./flash.sh -r -k kernel ??

9

  1. dmesg and grep some keywords like “tegradc” and “dp”

  2. “…” means just write the same one as how you flashed your board.

sudo ./flash.sh -r -k kernel-dtb jetson-xavier-nx-devkit-emmc mmcblk0p1

“-r” means skip the preparation of system.img
“-k kernel-dtb” means flashing the partition called “kernel-dtb”.

You can read l4t developer guide from this page to understand more about how this system works.

10

i bring the dmesg grep tegradc
but i’m not sure it means
i use dev.kit but i turn off the sor1 HDMI and turn on the sor1 DP

if i insert my module it can output 2 DP now???

test.txt (16.0 KB)

11

Hi,

  1. i use dev.kit but i turn off the sor1 HDMI and turn on the sor1 DP
    if i insert my module it can output 2 DP now???

It would be better if you can share us what have you modified. I cannot tell anything by just one comment here.
Based on your log, my answer is no. You didn’t modify it correctly. I can still see driver want to enable hdmi but not dp.

[ 1.480508] tegradc 15200000.nvdisplay: tegra_dc_parse_panel_ops: panel: /host1x/sor1/hdmi-display is not active
[ 1.480554] tegradc 15200000.nvdisplay: err:-19 parsing panel_ops

  1. i bring the dmesg grep tegradc but i’m not sure it means

These are driver logs which enable the tegradc. DC means Display Controller. Codes are under kernel/nvidia/drivers/video/tegra/dc/

13

You didn’t change the nvidia,active-panel under sor.

15

Yes, you have to change that from 0x64(hdmi-dipslay) to 0x13a (dp-display).

BTW, in our source code, we use human readable string but not hex values for phandle. If you download our kernel source, you shall see it.

16

Thank for helping me

but i didn’t understand last sentence

BTW, in our source code, we use human readable string but not hex values for phandle. If you download our kernel source, you shall see it

17

For example, this is the dts in the kernel source file. It is not hex value so easier to read.

image

You see hex value because you convert dtb file back to dts files directly. But it is fine. Your method should work too.
It is just hard to found some nodes sometimes.

19

How to convert like that!
i thought it is hard to read too

The source code is on our download center too.

i changed panel and refrash but driver want to hdmi not DP ㅜㅜ

Are you sure you update is taking effect on your device?
You can check each property under /proc/device-tree/

21

Hello @WayneWWW

Thanks for your help
all the flashing was finish

22

when i use ./flash -r -k kernel-dtb ~~~…

so i wonder if i flash with sdkmanager (include jetpack installation )
can i change dtb only?

That command will flash dtb only. You already tried that.

23

i mean if i do that it did not change anything

24

Hi,

No, if you use flash.sh with -r -k, it will flash only one partition and does not erase all emmc storage.
You can tell that based on the time to finish flash. If you run flash.sh with -r, -k it will finish quickly. You shall not see something that “APP” partition gets flashed.

Thus, I guess you didn’t do it correctly.

25

Hello @WayneWWW

can you tell me which place i should put .dtb file in the host pc