Jetson nano 4GB: LCD screen becomes blurred and indistinct during startup(Cboot)

Hello supports,
I am using Jetson nano HDMI port to drive my personal LCD screen(1920x720,pixel clock89.6H bank:128,v.Blank:9,H.FrontPorch:40,H.SyncWidth:32,H.ImageSize:300 …). In ubuntu, the LCD base on HDMI port connection is working properly,but during power up,LCD screen becomes blurred and indistinct during. I tried to change boot logo to 1920x720, it also cannot be fix. So, how can I fix this issues? If Cboot code is not provided, how can I fix this issues? I dont know CBOOT device tree. Any update, Cboot device tree, and this issue can be fix? HW conversion between HDMI and LCD(HDMI->LVDS->LCD), it cannot be controlled /reconfigured by MCU.
could you share related solution to fix this issues? Thanks a lot.

I think cboot only supports some common mode in cboot disp like 1080p/720p.

ok,thank you. if I’d like to update LCD other peremters, how can I update it?
pixel clock89.6H bank:128,v.Blank:9,H.FrontPorch:40,H.SyncWidth:32,H.ImageSize:300 …)

The mode is read from the edid of your panel.

Good day.
Can you please share how to handle EDID? where can I found this tools? more detailed.
I check other Cboot code not jeetson nano, tegrabl_edid.c ? or nvimp_util, this tool, I didnt find in Jetson nano.

…There is no tool from us to handle this part. The edid should be prepared by the panel vendor.

So we don’t provide tools for such change.

we are using OPEN LDI,not EDP. so how can I let my LCD working in Cboot period?

We don’t have method here since we don’t support the display mode your panel told us to use.

Hello again,
we have an third-party PCB board between LVDS LCD screen and Jetson nano HDMI output.
there is a microcontroller to control TI DS90UB949 , related controlled cannot be recofigure in running mode. we already wrote this info (pixel clock89.6H bank:128,v.Blank:9,H.FrontPorch:40,H.SyncWidth:32,H.ImageSize:300 ) to third party microcontroller, it’s working in Linux platfrom.but in Cboot mode, it’s not working properly. So I would like to know how to fix this issues?


抱歉 容我再用中文說明一次

  1. t210 cboot沒有open source, 所以要改動它基本不可能. 我們能提供的功能就是他能支援常見的1080p/720p 如果你的panel沒辦法支援這些mode, 那就沒有辦法了. 另外, 我們的cboot都是讀你的edid給的mode決定要跑哪哪個mode 如果你的EDID就是要我們跑 1920x720 我們不支援的mode, 那也沒辦法

  2. 說實話你那邊用哪個controller, 是open LDI 還是其他的東西對我們而言也不是很重要的資訊, 如果你是用Jetson的HDMI Pin, 那對我們而言他就是個HDMI Panel.

English version for other users:

  1. Basically t210 cboot is not open source, so basically it is not possible to change it and we only support common 1080p and 720p. If your panel does not support these modes, then it may not be supported. Also, we read the edid from your panel to decide which mode to run. If you edid just wants us to run 1920x720, then we cannot help either.

  2. What your controller in use or whether it is open NDI or not does not really matter here. If your panel is using HDMI pin of jetson, then it is a HDMI to us.

Hello Again,
If t210 cboot is not open source, can you share the whole datasheet for chip t210 ?

Thanks & regards


  1. 我不確定你所謂的datasheet是要哪些東西. 基本上各個Soc跟platform的資訊都提供在我們的download center.
    Jetson Download Center | NVIDIA Developer

  2. 另外想要補充一下, cboot跟kernel兩邊有支援的程度不一樣. 因為cboot只是算一個中間短暫的期間, 所以我們並沒有完整支援. 比方說好了, 可能你的panel在開進kernel之後是沒有問題的, 但是cboot端我們只有支援基本的mode.

Eng version:

  1. I don’t know which datasheet you are asking for. But every soc and platform info is on the DLC.

  2. Also, want to mention that actually what cboot can support is different from kernel. Cboot is only a transition part so may not have same functionality as kernel.
    Which means kernel may support the mode you are asking but cboot cannot.

eg. external interrupt PINs.

Please check the TRM.

share the link, thanks.

can you share NVIDIA logo raw bmp which was used to generate blob file by this tool

I thought it might be useful to simply add some EDID information: Every “plug-n-play” monitor, meaning HDMI or DisplayPort, has a wire known as the “DDC” wire. That wire is an i2c protocol method of producing a query from the graphics card to the monitor, and the monitor responds with a standardized listing of its abilities. Before this existed one would have a database of various monitor settings, and simply have someone name which monitor it was to pick among the database (this required human intervention). The DDC wire (producing the EDID data) removed that requirement since it lets any monitor provide its own specs in detail. The video driver accepts modes only from EDID.

If your monitor has a particular list of modes in EDID, then this is what you get. To change this would require either changing the EDID response in the monitor or intercepting this with an active adapter programmed to provide a different EDID. There are places in the kernel where one can edit to pick different defaults, but normally you would change actual EDID only if you are providing a monitor which does not natively supply EDID and you are able to program the i2c response.