Need Help Enabling HDMI on Debix Model A

[Laurent Pinchart]

Hi Tarang,

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 at imx8mp-debix:~$ dmesg | grep -iE "drm|hdmi"
> [    0.121979] /soc at 0/bus at 32c00000/display-bridge at 32fc4000: Fixed dependency cycle(s) with /soc at 0/bus at 32c00000/hdmi at 32fd8000
> [    0.122164] /soc at 0/bus at 32c00000/hdmi at 32fd8000: Fixed dependency cycle(s) with /soc at 0/bus at 32c00000/display-bridge at 32fc4000
> [    0.127417] /soc at 0/bus at 32c00000/hdmi at 32fd8000: Fixed dependency cycle(s) with /hdmi-connector
> [    0.127608] /hdmi-connector: Fixed dependency cycle(s) with /soc at 0/bus at 32c00000/hdmi at 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 at 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 ?

> Could you please help me out or point me in the right direction?
> 
> Thank you for your time.
> 
> Best Regards,
> Tarang

-- 
Regards,

Laurent Pinchart