LCD flickering on i.MX7D Colibri after kernel upgrade

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Hi, I’m the Toradex AI Assistant.

I might make mistakes or occasionally get you wrong. Our support team will step in if needed.

I’d be glad to help troubleshoot the LCD flickering issue on your i.MX7D Colibri module! To provide the most accurate guidance for your specific setup, could you let me know which OS and version you are running?

Additionally, please run the tdx-info command on your device to get detailed hardware and software information. You can find more details about this command at Getting Device Information with Tdx-Info | Toradex Developer Center

Common Kernel 6.x Display-Related Changes

Based on the available documentation, here are key areas that commonly affect display functionality when upgrading to newer kernels:

Device Tree Bridge Requirements

One significant change in newer kernels is the requirement for proper bridge declarations in device trees (1). The LCDIF driver now expects explicit bridge and display chain node definitions, which may not have been required in older kernels (1).

For kernel 6.x, you need to ensure:

  • Both the controller (&lcdif) and any bridge nodes are set to status = "okay" (1)
  • Proper ports and endpoints are defined to connect the controller to the display chain (1)

Device Tree Display Configuration

For i.MX7 platforms, the display configuration typically involves the &lcdif node (1). A proper configuration should include:

&lcdif {
    status = "okay";
    display = <&display0>;
    
    display0: lcd-display {
        bits-per-pixel = <24>;
        bus-width = <18>;
        
        display-timings {
            native-mode = <&timing_wvga>;
            
            timing_wvga: 800x480 {
                clock-frequency = <33260000>;
                hactive = <800>;
                vactive = <480>;
                hback-porch = <40>;
                hfront-porch = <88>;
                vback-porch = <33>;
                vfront-porch = <10>;
                hsync-len = <154>;
                vsync-len = <2>;
                de-active = <1>;
                hsync-active = <0>;
                vsync-active = <1>;
                pixelclk-active = <1>;
            };
        };
    };
};

(1)

Key Areas to Verify

  1. Display Timing Parameters: Ensure your clock frequency and timing parameters match your display specifications (1)
  2. Bridge Connections: Verify that any display bridges are properly declared and connected (1)
  3. Pin Configuration: Check that display pins are correctly configured in the device tree (2)

Device Tree Customization Process

If you need to modify your device tree configuration, you can follow the process outlined in the documentation (2):

  1. Identify the base device tree for your i.MX7D Colibri module (2)
  2. Create a custom device tree with the necessary modifications (2)
  3. Compile the device tree using the appropriate make commands (2)
  4. Deploy the updated device tree to your system (2)

Once you provide your specific OS version and hardware details, I can offer more targeted guidance for your exact configuration.

Best regards,
Toradex AI Assistant.

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