i.MX8M Nano MIPI Display Error

[jimmyli]

Hi,

     Linux: Linux 5.4.24_2.1.0

     CPU: MIMX8MN1DVTJZAA

    Description:

    1>When power on, uboot is OK while it can be displayed; --NXP logo can be display

    2>Run into Kernel, the LCD is black all the way.

        Below is log:

        [ 1.214260] imx-drm 32c00000.bus:display-subsystem: bound imx-lcdif-crtc.0 (ops lcdif_crtc_ops)
        [ 1.223655] imx_sec_dsim_drv 32e10000.dsi_controller: version number is 0x1060200
        [ 1.232394] imx_sec_dsim_drv 32e10000.dsi_controller: Failed to attach bridge: 32e10000.dsi_controller
        [ 1.241775] imx_sec_dsim_drv 32e10000.dsi_controller: failed to bind sec dsim bridge: -517
        [ 1.250099] imx-drm 32c00000.bus:display-subsystem: failed to bind 32e10000.dsi_controller (ops imx_sec_dsim_ops): -517
        [ 1.260977] imx-drm 32c00000.bus:display-subsystem: master bind failed: -517

    3>Run modetest twice, it can display.

         command: modetest -M imx-drm -D 0 -s 35@33:720x1280

         Note: must run modetest twice, only one time can't display.

    4>After it can display, calling framebuffer（/dev/fb0）can display well.

    Question:

    Why "2>" happens, how to fix it?

    Thanks.

[igorpadykov]

Hi jimmyli

one can check if correct dts file was used in the case:

https://source.codeaurora.org/external/imx/linux-imx/tree/arch/arm64/boot/dts/freescale/imx8mn-ddr4-...

for custom lcd may be useful :

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/Setting-i-MX8M-Mini-and-Nano-MIPI-DPHY-C...

Also as MIMX8MN1DVTJZAA has not gpu per Table 3. Orderable part numbers

i.MX 8M Nano Applications Processor Datasheet for Consumer Products

disable gpu in dts :

https://source.codeaurora.org/external/imx/linux-imx/tree/arch/arm64/boot/dts/freescale/imx8mn-ddr4-...

Best regards
igor

[jimmyli]

Hi Igor,

      We have tested as you said, but the problem has not been solved yet.

      Hope you can check again.

      Thanks a lot.

[igorpadykov]

had you disabled gpu in dts :

https://source.codeaurora.org/external/imx/linux-imx/tree/arch/arm64/boot/dts/freescale/imx8mn-ddr4-...

Best regards
igor

[jimmyli]

Hi Igor,

        Sorry that I have not fixed the problem yet.

        It is urgent that we have to finish the project.

        Attachments are dts, dtsi, and log.

        Hope you can help us to resolve the problem.

        Thanks very much.

[jimmyli]

Hi igor,

      Yes, I have disabled the GPU in dts, but it can't fix the problem.

      Thanks.

/*
&gpu {
	assigned-clocks = <&clk IMX8MN_CLK_GPU_CORE_SRC>,
			<&clk IMX8MN_CLK_GPU_SHADER_SRC>,
			<&clk IMX8MN_CLK_GPU_AXI>,
			<&clk IMX8MN_CLK_GPU_AHB>,
			<&clk IMX8MN_GPU_PLL>,
			<&clk IMX8MN_CLK_GPU_CORE_DIV>,
			<&clk IMX8MN_CLK_GPU_SHADER_DIV>;
	assigned-clock-parents = <&clk IMX8MN_GPU_PLL_OUT>,
			<&clk IMX8MN_GPU_PLL_OUT>,
			<&clk IMX8MN_SYS_PLL1_800M>,
			<&clk IMX8MN_SYS_PLL1_800M>;
	assigned-clock-rates = <0>, <0>, <800000000>, <400000000>, <1200000000>,
			<400000000>, <400000000>;
	status= "okay";
};
*/

[jimmyli]

Hi igor,

       Thanks for your reply!

       I will try as you said.