Hi Tarang, On Mon, Apr 07, 2025 at 02:06:35PM +0000, Tarang Raval wrote: > > 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?
That's a plausible explanation. The 2D GPU is probably not used by the compositor, but a 3D GPU could be required. I'd recommend checking the system logs to see why the compositor (or session manager) failed to start. > > > Could you please help me out or point me in the right direction? > > > > > > Thank you for your time. -- Regards, Laurent Pinchart
