I subtracted the manufacture of a compatible support board for Xavier NX SOM. The problem is they made a mistake on the screen detection polarity (the HPD signal used in the HDMI controller). Indeed, they forgot to put an inverter … Morality, I would like to make up for it by reversing the detection polarity of the HPD. I know it is possible with a modification of the device tree. it is necessary to change the property of “out-flags” by passing it from “TEGRA_DC_OUT_HOTPLUG_LOW” to “TEGRA_DC_OUT_HOTPLUG_HIGH”. the problem is, i don’t know which dtsi file i can do it in.
Thanks for your help.
What I am going to teach is how to find out the dts file you are using.
Please turn on the board, run dmesg and grep “dts”. It shall tell you which dts file is in use.
Then, download our DT source from dlc, use find command to find out that file location.
With the file location, you should be able to use grep to find out which file has TEGRA_DC_OUT_HOTPLUG_LOW.
I find the dts file using dmesg. I have made the modification putting TEGRA_DC_OUT_HOTPLUG_HIGH in spite of TEGRA_DC_OUT_HOTPLUG_LOW.
I flashed my Xavier NX module and I put it on my custom board.
The HPD reverse polarity is running !
Thank you very much.