Hello,
We are developing based on the Jetson AGX Orin platform. The SOM is the same as the Development Kit, but we have developed a custom carrier board.
By default, the Development Kit uses DisplayPort output, but we are trying to switch the output to Micro HDMI on our custom board.
We referred to the following NVIDIA forum thread:
- PinMux Configuration
Modified the following file:
/Linux_for_Tegra/bootloader/generic/BCT/tegra234-mb1-bct-pinmux-p3701-0000-a04.dtsi
The relevant pin configuration snippet:
dp_aux_ch0_hpd_pm0 {
nvidia,pins = “dp_aux_ch0_hpd_pm0”;
nvidia,function = “rsvd1”;
nvidia,pull = <TEGRA_PIN_PULL_NONE>;
nvidia,tristate = <TEGRA_PIN_ENABLE>;
nvidia,enable-input = <TEGRA_PIN_ENABLE>;
nvidia,io-high-voltage = <TEGRA_PIN_DISABLE>;
nvidia,lpdr = <TEGRA_PIN_DISABLE>;
};
Although we considered setting the function to “hdmi”, we referred to the Orin_Jetson_Series_Pinmux_Config_Template_2.0.xlsm document, which only defines “DP” for this pin, so we used “rsvd1”.
According to the schematic, the HPD (Hot Plug Detect) signal is active high per HDMI specification, but the signal is inverted to active low by a BJT before entering the SoC. Therefore, TEGRA_PIN_PULL_NONE was used.
1.2 GPIO Modification
Unsure exactly what changes are required, but modified:
/Linux_for_Tegra/bootloader/tegra234-mb1-bct-gpio-p3701-0000-a04.dtsi
Added TEGRA234_MAIN_GPIO(M, 0) for HPD.
- DCB Configuration
Used the official NVIDIA-provided file:
tegra234-dcb-p3701-0000-a02-p3737-0000-a01_hdmi.dtsi
The file contains a dcb-image definition.
Added HPD config as follows:
// for HDMI, 2025-06-23, HPD (Hot Plug Detect) Low Active
display@13800000 {
compatible = “nvidia,tegra234-hdmi”;
nvidia,display-type = “hdmi”;
status = “okay”;
os_gpio_hotplug_a = <&gpio TEGRA234_MAIN_GPIO(M, 0) GPIO_ACTIVE_LOW>;
};
3. DTS Extracted from dtb (tegra234-p3737-0000+p3701-0008-nv.dtb)
display@13800000 {
compatible = “nvidia,tegra234-hdmi”;
power-domains = <0x03 0x03>;
nvidia,num-dpaux-instance = <0x01>;
reg-names = “nvdisplay\0dpaux0\0hdacodec\0mipical”;
reg = <0x00 0x13800000 0x00 0xeffff 0x00 0x155c0000 0x00 0xffff 0x00 0x242c000 0x00 0x1000 0x00 0x3990000 0x00 0x10000>;
interrupt-names = “nvdisplay\0dpaux0\0hdacodec”;
interrupts = <0x00 0x1a0 0x04 0x00 0x1a3 0x04 0x00 0x3d 0x04>;
nvidia,bpmp = <0x03>;
clocks = <0x03 0x54 …>;
clock-names = “nvdisplayhub_clk\0nvdisplay_disp_clk\0nvdisplay_p0_clk\0nvdisplay_p1_clk\0dpaux0_clk\0fuse_clk\0dsipll_vco_clk\0dsipll_clkoutpn_clk\0dsipll_clkouta_clk\0sppll0_vco_clk\0sppll0_clkoutpn_clk\0sppll0_clkouta_clk\0sppll0_clkoutb_clk\0sppll0_div10_clk\0sppll0_div25_clk\0sppll0_div27_clk\0sppll1_vco_clk\0sppll1_clkoutpn_clk\0sppll1_div27_clk\0vpll0_ref_clk\0vpll0_clk\0vpll1_clk\0nvdisplay_p0_ref_clk\0rg0_clk\0rg1_clk\0disppll_clk\0disphubpll_clk\0dsi_lp_clk\0dsi_core_clk\0dsi_pixel_clk\0pre_sor0_clk\0pre_sor1_clk\0dp_link_ref_clk\0sor_linka_input_clk\0sor_linka_afifo_clk\0sor_linka_afifo_m_clk\0rg0_m_clk\0rg1_m_clk\0sor0_m_clk\0sor1_m_clk\0pllhub_clk\0sor0_clk\0sor1_clk\0sor_pad_input_clk\0pre_sf0_clk\0sf0_clk\0sf1_clk\0dsi_pad_input_clk\0pre_sor0_ref_clk\0pre_sor1_ref_clk\0sor0_ref_pll_clk\0sor1_ref_pll_clk\0sor0_ref_clk\0sor1_ref_clk\0osc_clk\0dsc_clk\0maud_clk\0aza_2xbit_clk\0aza_bit_clk\0mipi_cal_clk\0uart_fst_mipi_cal_clk\0sor0_div_clk”;
resets = <0x03 0x10 0x03 0x08 0x03 0x03 0x03 0x25>;
reset-names = “nvdisplay_reset\0dpaux0_reset\0dsi_core_reset\0mipi_cal_reset”;
hdcp_enabled;
status = “okay”;
memory-region = <0x20b>;
nvidia,disp-sw-soc-chip-id = <0x2350>;
interconnects = <0x58 0x92 0x59 0x58 0xa1 0x59>;
interconnect-names = “dma-mem\0read-1”;
iommus = <0x113 0x01>;
non-coherent;
nvidia,dcb-image = [55 aa …];
nvidia,display-type = “hdmi”;
os_gpio_hotplug_a = <0xf1 0x60 0x01>;
phandle = <0x20c>;
nvdisplay-niso {
compatible = "nvidia,tegra234-display-niso";
iommus = <0x04 0x07>;
dma-coherent;
};
- Current Issue
We are not sure if our custom board has boot issues.
When connecting the monitor via Micro HDMI, no display output appears.
According to NVIDIA documentation, only the DCB image and HPD settings should be needed, but it seems not working in our case.
Question
What could be wrong or missing in our configuration? Is there anything else to consider beyond DCB and HPD settings to get HDMI output working on a custom carrier board for Jetson AGX Orin?
Thank you for any help or suggestions.