TX2(i): Disable spread spectrum clock

Robotics & Edge Computing Jetson & Embedded Systems Jetson TX2
1

Hello,

I found here the following link:
https://devtalk.nvidia.com/default/topic/1066076/jetson-tx2/how-to-disable-ssc-/?offset=2#5398648

It explains how to disable SCC in TX2:
“Please convert bpmp dtb to dts and put this to it.”

Can you please explain where can I find “dpmp dtb” ?

Thank you in advance,
Zvika

2

Please take a look:
https://devtalk.nvidia.com/default/topic/1066505/jetson-tx2/disable-spread-spectrum-in-tx2-r28-2-1/post/5402814/#5402814

3

Hello,

Thank you very much for your reply.

Is there a documentation what is the purpose of each dtb ?

Best regards,
Zvika

4

Hi,

How about reading the l4t documentation first?
https://developer.nvidia.com/embedded/dlc/l4t-documentation-28.3

5

Hello,

I tried:
sudo ./flash.sh -d bootloader/t186ref/tegra-186-a02-bpmp-storm-p3489-a00-00-ta795sa-ucm1.dtb jetson-tx2i mmcblk0p1

But this caused the TX2i to hang while booting.
I got the NVIDIA logo forever.

In the documentation, I did not find what is each dtb.

Thank you,
Zvika

6

Please do the full flash instead of each dtb in this case.

7

Hello,

I did not understand your reply.

What should I do after:
sudo ./flash.sh jetson-tx2i mmcblk0p1 ?

The original jetson-tx2i.conf contains the line:
BPFDTB_FILE=tegra-186-a02-bpmp-storm-p3489-a00-00-ta795sa-ucm1.dtb

Should I do any modification in a dtb \ conf ?

Thank you very much for your help,
Zvika

8

Hello,

Follwing are the steps I did:

  1. dtc -I dtb -O dts tegra-186-a02-bpmp-storm-p3489-a00-00-ta795sa-ucm1.dtb > tegra-186-a02-bpmp-storm-p3489-a00-00-ta795sa-ucm1.dts

  2. cp tegra-186-a02-bpmp-storm-p3489-a00-00-ta795sa-ucm1.dts tegra-186-a02-bpmp-storm-p3489-a00-00-ta795sa-ucm1-ssc-disable.dts

  3. add the following section in tegra-186-a02-bpmp-storm-p3489-a00-00-ta795sa-ucm1-ssc-disable.dts
    clocks {
    …
    clock@plle {
    clk-id = <0x200>;
    /* disable ssc on PLLE */
    pll_freq_table = <38400000 100000000 2 125 24 (-1) (-1) (-1) (-1)>;
    };
    };

  4. dtc -I dts -O dtb tegra-186-a02-bpmp-storm-p3489-a00-00-ta795sa-ucm1-ssc-disable.dts > tegra-186-a02-bpmp-storm-p3489-a00-00-ta795sa-ucm1-ssc-disable.dtb

  5. Modified jetson-tx2i.conf to use the new tegra-186-a02-bpmp-storm-p3489-a00-00-ta795sa-ucm1-ssc-disable.dtb

Thank you,
Zvika