i.MX93 lcdif. XRGB8888 framebuffer to bus format RGB888

[spawn]

Hello,

I observe some flickering and others glitches when trying to setup a parallel LCD with imx93.

I attached a picture of the output of the fb-test command. In the yellow rectangles there are glitches around pixels set to print text "GREEN" and "RED". In the yellow circle there is a glitch, as if lines where pixels were set (for the text) were shifted left.

fb-test output

The framebuffer is configured as XRGB8888 (bpp 32), size 800x480. The bus format is configured as rgb888.

The output of the fbset command is :

mode "800x480-0"
        #  0.000 MHz, H: 0.000 kHz, V: 0.000 Hz
        geometry 800 480 800 480 32
        timings 0 0 0 0 0 0 0
        accel true
        rgba 8/16,8/8,8/0,0/0
endmode

Device tree node for bus format (MEDIA_BUS_FMT_RGB888_1X24) :

&parallel_disp_fmt {
  pinctrl-names = "default";
  pinctrl-0 = <&pinctrl_lcdif>;
  fsl,interface-pix-fmt = "rgb888";
  status = "okay";

  ports {
    port@1 {
      reg = <1>;

      display_out: endpoint {
        remote-endpoint = <&panel_in>;
      };
    };
  };
};

  Panel configuration :

  panel {
    compatible = "panel-dpi";
    power-supply = <&reg_vdd_3v3>;
    backlight = <&backlight>;

    panel-timing {
      clock-frequency = <33260000>;
      hactive = <800>;
      vactive = <480>;
      hfront-porch = <40>;
      hback-porch = <88>;
      hsync-len = <128>;
      vfront-porch = <35>;
      vback-porch = <8>;
      vsync-len = <2>;

      de-active = <1>;
      pixelclk-active = <1>;
    };

    port {
      panel_in: endpoint {
        remote-endpoint = <&display_out>;
      };
    };
  };

&lcdif {
  status = "okay";
};

As far as I know I configured things the right way, but maybe I missed something. Could you please advise ?

The driver used is lcdifv3, from linux 6.1.55.

[Bio_TICFSL · Accepted solution]

Hello,

I guess this issue is due to clock frequency check your clock.

Regards