U:1920x1080p-35

[fulinux]

Dear all,

this is my configure of lcd panel:

    mxcfb1: fb@0 {

            compatible = "fsl,mxc_sdc_fb";

            disp_dev = "ldb";

            interface_pix_fmt = "RGB24";

            mode_str ="LDB-1080P60";

            default_bpp = <32>;

            int_clk = <0>;

            late_init = <0>;

            status = "okay";

    };

&ldb {

    status = "okay";

    split-mode;

    lvds-channel@0 {

        fsl,data-mapping = "spwg";

        fsl,data-width = <24>;

        crtc = "ipu2-di0";

        primary;

        status = "okay";

        display-timings {

            native-mode = <&timing0>;

            timing0: hsd100pxn1 {

                clock-frequency = <83000000>;

                hactive = <1920>;

                vactive = <1080>;

                hback-porch = <80>;

                hfront-porch = <68>;

                vback-porch = <15>;

                vfront-porch = <15>;

                hsync-len = <12>;

                vsync-len = <8>;

            };

        };

    };

    lvds-channel@1 {

        fsl,data-mapping = "spwg";

        fsl,data-width = <24>;

        crtc = "ipu2-di1";

        status = "disabled";

        display-timings {

            native-mode = <&timing1>;

            timing1: hsd100pxn1 {

                clock-frequency = <83000000>;

                hactive = <1920>;

                vactive = <1080>;

                hback-porch = <80>;

                hfront-porch = <68>;

                vback-porch = <15>;

                vfront-porch = <15>;

                hsync-len = <12>;

                vsync-len = <8>;

            };

        };

    };

};

kernel:

# cat /proc/cmdline

noinitrd console=ttymxc0,115200 root=/dev/mmcblk0p1 rw init=/linuxrc video=mxcfb0:dev=ldb,LDB-1080P60,if=RGB24,bpp=32 consoleblank=0 ldb=spl0 ldo_active=on

# cat /sys/class/graphics/fb0/modes

U:1920x1080p-35

why my refresh frequency is 35Hz, i need 60Hz or 75Hz, how can i do that?

thank you,

fulinux.

[marcchapdelaine · Accepted solution]

Hi Fulinux,

I found the issue in the thread I created: i.MX6Q Dual channel LVDS output in kernel 3.10.53 / 3.14.52

Your frequency may be wrong. I assume you are using the two LVDS channel lines to drive one screen that has an LVDS clock of 83Mhz.

Inside the "Documentation/devicetree/bindings/video/fsl,ldb.txt" file describing the ldb section, it says that if split mode is specified you do not need to provide a lvds-channel@1. I think you can remove this section.

Try this:

====

&ldb {

    status = "okay";

    split-mode;

    lvds-channel@0 {

        fsl,data-mapping = "spwg";

        fsl,data-width = <24>;

        crtc = "ipu2-di0";

        primary;

        status = "okay";

        display-timings {

            native-mode = <&timing0>;

            timing0: hsd100pxn1 {

                clock-frequency = <166000000>;

                hactive = <1920>;

                vactive = <1080>;

                hback-porch = <80>;

                hfront-porch = <68>;

                vback-porch = <15>;

                vfront-porch = <15>;

                hsync-len = <12>;

                vsync-len = <8>;

            };

        };

    };

  };

[fulinux]

thank you!

[joanxie]

did you use freescale demo image? let me reproduce it, I tested it on old bsp.

[fulinux]

my lcd panel is 1920x1080, i need it's refresh frequency is 75hz, it is schematics:

How to configure dts.

[fulinux]

no, i build myself. it shows 1920x1080p-60  in old kernel linux-3.0. is it wrong with my dts configure.

[joanxie]

did you use imx6 board? if yes, could you share your ldb.c file, which have the struct fb_videomode. and pls confirm if board and lvds can support it or not. and try to confirm if you set the correct refresh rate value in the source code or not.

[fulinux]

Dear GuanQiong,

will you answer my questions, i need help

[fulinux]

Dear GuanQiong,

which ldb.c file? i have never modified anything code in kernel,just modified dts file, my kernel is linux-4.1.15, board is imx6q,should i modify some code file?Would you please detail your replay for our sample?