Hi Laurent, Thanks for the response.
> On Mon, Apr 07, 2025 at 11:10:23AM +0000, Tarang Raval wrote: > > Hi Laurent, > > > > I’m trying to bring up HDMI on the Debix Model A board using the > > mainline kernel, but I’m currently facing issues. > > > > I saw that you tested the patch for HDMI support on this board in > > mainline, so I am hoping you could help me figure out what might be > > missing. > > > > To clarify — I'm using the prebuilt image provided by Debix, but I replaced > > the kernel image and the device tree (DTS) file in the /boot directory with > > ones built from the mainline kernel. > > > > I’ve enabled the following configurations in the kernel: > > CONFIG_DRM_DISPLAY_CONNECTOR=y > > CONFIG_DRM_IMX8MP_DW_HDMI_BRIDGE=y > > CONFIG_DRM_IMX8MP_HDMI_PVI=y > > CONFIG_DRM_IMX_LCDIF=y > > CONFIG_PHY_FSL_SAMSUNG_HDMI_PHY=y > > > > When I boot the board, I see the following HDMI/DRM related logs: > > debix@imx8mp-debix:~$ dmesg | grep -iE "drm|hdmi" > > [ 0.121979] /soc@0/bus@32c00000/display-bridge@32fc4000: Fixed > > dependency cycle(s) with /soc@0/bus@32c00000/hdmi@32fd8000 > > [ 0.122164] /soc@0/bus@32c00000/hdmi@32fd8000: Fixed dependency cycle(s) > > with /soc@0/bus@32c00000/display-bridge@32fc4000 > > [ 0.127417] /soc@0/bus@32c00000/hdmi@32fd8000: Fixed dependency cycle(s) > > with /hdmi-connector > > [ 0.127608] /hdmi-connector: Fixed dependency cycle(s) with > > /soc@0/bus@32c00000/hdmi@32fd8000 > > [ 1.947962] imx8mp-dw-hdmi-tx 32fd8000.hdmi: Detected HDMI TX controller > > v2.13a with HDCP (SAMSUNG HDMI TX PHY) > > [ 1.949220] imx8mp-dw-hdmi-tx 32fd8000.hdmi: registered DesignWare HDMI > > I2C bus driver > > [ 1.956365] [drm] Initialized imx-lcdif 1.0.0 for > > 32fc6000.display-controller on minor 0 > > [ 2.016601] imx-lcdif 32fc6000.display-controller: [drm] fb0: > > imx-lcdifdrmfb frame buffer device > > [ 8.380915] systemd[1]: Starting Load Kernel Module drm... > > > > > > I also checked that the display's modeline is recognized under sysfs : > > > > root@imx8mp-debix:~# ls /sys/class/drm/card0-HDMI-A-1/ > > connector_id dpms modes subsystem/ > > ddc/ edid power/ uevent > > device/ enabled status > > > > However, there is still no HDMI output on the display. Instead, > > I only see a white blinking cursor on the screen.. I'm not sure > > what I'm missing. > > The white blinking cursor means the display is working from the kernel > point of view. What are you expecting, are you running an X server or > Wayland compositor ? I'm expecting to see the Ubuntu desktop environment on the HDMI display — just like how it appears with the original prebuilt image provided by Debix. I'm running the default Ubuntu 22.04 LTS prebuilt image, and I only replaced the Image and .dtb file I'm not explicitly launching an X server or Wayland compositor myself However, based on your response, I now realize that I may also need to enable GPU support in the mainline device tree. Specifically, I believe I need to enable the gpu2D and gpu3D nodes to allow the graphical environment to start properly and render the desktop over HDMI. Does that sound correct, or is there anything else I should check or enable? Best Regards, Tarang > > Could you please help me out or point me in the right direction? > > > > Thank you for your time. > > > > Best Regards, > > Tarang > > -- > Regards, > > Laurent Pinchart
