DP compliance TX_PULL enable

Hi Nvidia teams,
We’d like to tuning DP SI compliance for 4K@30 panel.
To enable 0x1380c130 bit 22 TX_PU, we can pass the compliance.
We are trying to set this feature into dcb file(tegra234-dcb-p3767-0000-dp.dtsi) by dcb_tool, but can not find the value inside the dtsi file.

Would you kindly to show us which property is the right one we should set??

0x1380c130 register statue :
before insert DP cable : 0x200
with DP cable insert : 0x206
we would like the value to be 0x400200 / 0x400206.

dcb_tool relative property:
TX PU Value: 0x40460f
DispMacroLinkRateInfoEntrySORTXPULinkValue - 0x6

Regards

Are you talking about you already set TX PU value in dcb tool but it does not take effect after flash?

Hi WayneWWW,

No , the problem is we don’t know which setting could effect the TX PU value when using dcb_tool.
we just setting the register value directly by devmem tool to pass the compliance testing.

Regards

Hi,

Please use the dcb_tool from rel-36 to do this configuration.

Hi WayneWWW,

to use dcb_tool from BSP 36, it deed show “SOR TX Pu” , and default value is 0x1
image

Does it mean 0x1380c130 bit 22 default already is pull-up enabled ?
image

If default pull-up enabled, why we get register value =0x206 , not 0x400206?

Regards

Hi @yi-chia.lan

Could you help flash the new dcb image with new value to your board and see what register value it is?

Hi WayneWWW,

Need you help to show(guide) me where could I find the new dcb image ?

Regards

I don’t quite understand your question… the dcb tool can modify your dtsi file and create a new dtsi file.

Put that new dtsi file to your kernel device tree and do full flash. Must do full flash.

Hi WayneWWW,

understood.

But, original dcb file in 35.4.1 already show “TX Pu”= 0x1
I also try to set “TX Pu” to 0x0 and flash to device
It seems register 0x1380c130 always get value 0x206. (no matter TX Pu = 0x0 or 0x1)

Regards

Could you check if something else modified in your dcb image will take effect after your update?

I just want to make sure the way you update a dcb image is correct or not.

Hi WayneWWW,

I do compare original dcb file and modified dcb file,
the difference is : header remove from modified dtsi

Regards

Hi,

Are you sure you modified and save it? I just tried the same thing on my side but I can see hex value change in dcb image.

Hi WayneWWW,

Here is my step for modified and save , if anything wrong, please let me know.

My Target is to set “SOR TX Pu” as 0x1
image

original value in dcb image file is :
image

STEP:
$ dcb_tool -m tegra234-dcb-p3767-0000-dp.dtsi
image

Press 4 in console (Show DP settings)
image

Press 7 in console (Modify DP settings"

Select 1 in console and enter 0x1 in hex (SOR Tx Pu)

Press 6,4,8,16,9 to Exit dct_tool

To diff difference between original file and modified file.

Hi,

Please try something else like 0xa. I don’t think that one is just a bool…

Hi WayneWWW,

I have tried several value on “SOR TX Pu” , such as 0xa, 0x0, 0xf, 0x5 …, and flash image to device to check register value.

I also double check the modified value was in dcb image.
But, all of these settings read back 0x206 on register 0x1380c130.

Is it possible that dcb image is correct , but driver didn’t use it??
or , which value is correct to set for “SOR TX Pu” ?

Regards

Hi,

請問你是說dcb image的值確實有變動了但是register讀出來都一樣嗎?

Hi WayneWWW,

是的.
無論dcb image改了甚麼數值, register都是同樣的數值

跟你確認一下,
Linux_for_Tegra/bootloader底下的dtb file有包含到你的dcb change嗎?

Hi WayneWWW,

您是指bootloader底下的哪個檔案??

我回答不了你的問題…因為這是你的BSP.

你放dcb image的dtb file會有一個檔名. 就是你的kernel dtb.

這個檔案在燒錄的時候也會被bootloader dtb拿去使用. 所以應該會備份一樣的檔名在Linux_for_Tegra/bootloader.

有時候這個檔案不會被更新到, 導致bootloader dtb一直使用到舊的檔案