Horizontally shrunken picture - imx8mp with LVDS display on resolution 1024x600

Technical Support
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Hi Jaroslav,

It sounds like you’re experiencing an issue with the horizontal timing parameters of your LVDS display. Here are a few suggestions to help you troubleshoot and potentially resolve the issue:

  1. Clock Frequency: Ensure that the clock frequency you are using is correct and supported by both the display and the Verdin iMX8MP. You mentioned that 51.2 MHz is not supported, and you selected 51.6096 MHz. Verify that this frequency is within the tolerance range of your display.

  2. Horizontal Timing Parameters: The horizontal timing parameters (hsync-len, hfront-porch, hback-porch) are crucial for proper display operation. Double-check the datasheet of the WinStar WF70A8TYAHLNT0# display to ensure these values are correct. Sometimes, incorrect timing parameters can cause the display to not cover the entire screen or appear shrunken.

  3. Device Tree Overlay: Your device tree overlay looks mostly correct, but you might want to experiment with slight adjustments to the horizontal timing parameters. For example, try increasing or decreasing the hfront-porch and hback-porch values slightly to see if it affects the display output.

  4. Driver Modifications: Since you mentioned making changes to the imx8mp-ldb.c file, ensure that these changes are correctly implemented and do not introduce any timing issues. Sometimes, minor changes in the driver can have significant impacts on the display output.

  5. Testing with Known Good Configuration: If possible, test your display with a known good configuration or another display to isolate whether the issue is with the display, the device tree configuration, or the driver.

  6. Contact Technical Support: If the issue persists, consider reaching out to Toradex technical support for further assistance. They might have more insights or specific patches for the Verdin iMX8MP and your display.

Here is a slightly adjusted version of your device tree overlay with minor changes to the horizontal timing parameters:

/* WF70A8TYAHLNT0 panel with a resolution of 1024x600 */
/dts-v1/;
/plugin/;

&panel_lvds {
    status = "okay";
    data-mapping = "vesa-24";
    width-mm = <154>;
    height-mm = <86>;

    panel-timing {
        clock-frequency = <51609600>;
        hactive = <1024>;
        vactive = <600>;
        hsync-len = <70>;
        hfront-porch = <150>;  // Adjusted value
        hback-porch = <100>;   // Adjusted value
        vsync-len = <11>;
        vfront-porch = <12>;
        vback-porch = <12>;
        
        de-active = <1>;
        hsync-active = <0>;
        vsync-active = <0>;
    };
    
    port {
        panel_lvds_native_in: endpoint {
            remote-endpoint = <&lvds_out>;
        };
    };
};

&lvds_out{
    remote-endpoint = <&panel_lvds_native_in>;
};

&lcdif2 {
    status = "okay";
};

&ldb {
    status = "okay";
};

&ldb_phy {
    status = "okay";
};

&gpu_2d {
    status = "okay";
};

&gpu_3d {
    status = "okay";
};

&mix_gpu_ml {
    status = "okay";
};

&ml_vipsi {
    status = "okay";
};

Try these adjustments and see if they help resolve the issue. If not, further investigation into the clock signal and timing parameters might be necessary.

Best Regards,
[Your Name]

Please, also check if these links can help you solve your problem:

Verdin IMX8MP: Use native LVDS and HDMI Interface.