Enable LVDS

  • Hi, 

    Does the LVDS should work without change in the dtb . 

    I plugged an LVDS screen on dev board and i have nothing on screen . 

    Same after have enable lvds-channel@0 and lvds-channel@1 in the dtb. 

    Output error in dmesg : 

    [    2.056545] [drm] Initialized vivante 1.0.0 20170808 for 40000000.mix_gpu_ml on minor 0
    [    3.099364] imx-drm display-subsystem: bound imx-lcdifv3-crtc.0 (ops lcdifv3_crtc_ops)
    [    3.107372] imx-drm display-subsystem: bound imx-lcdifv3-crtc.1 (ops lcdifv3_crtc_ops)
    [    3.115349] imx-drm display-subsystem: bound imx-lcdifv3-crtc.2 (ops lcdifv3_crtc_ops)
    [    3.145301] imx-drm display-subsystem: failed to bind 32c00000.bus:ldb@32ec005c (ops imx8mp_ldb_ops): -22
    [    3.159618] imx-drm display-subsystem: master bind failed: -22

    Do you have an idea



  • Dear @O. JUD, By default, our image can support the following LVDS panel(HYDIS HV150UX2-100 18 dual panels). Don't need to change anything in the dtb. we recommend the following steps to set up the LVDS Panel for IMX8MP,

    1. Connect the LVDS panel(HYDIS HV150UX2-100 18 dual panels).
    2. Change the U-boot parameter as below.
     U-BOOT>setenv fdt_file 'lec-imx8mp-hydis-hv150ux2.dtb'
    3. Boot to Linux
    4. Power on and boot into OS.
    5. Check LVDS output.

  • I don't use HYDIS screen but an AUO G150XAN02.2 . 

    I will have a look in the HYDIS dts and I think I have to adapt it.

    Can you point me on all elements in the dtb that enable HYDIS lvds screen?  I think that ldb@...part should be modified , right ? 

    Is there a power-regulator for the lvds to enable in the dts ? 

    Do the LVDS and HDMI can work at same time?





  • Dear @O. JUD, You can either use LVDS or HDMI. Both can't be used simultaneously. You don't need to change the dtb for HYDIS screen. For more details, you can refer NXP website.

  • @Kothandaraman Kannadasan  I plugged my display and set the environnement in U-boot as you explained .  The display starts now (can see the backlight ) and a white background but nothing more. 

    I have no LDVS device in /sys/class/drm/  . I understand that the display is not well detected. 

    What do you think ?  can you help me with the panel et panel-timings setting in the DTS for my display ? 

  • I tried the DTS for LVDS screeen "lec-imx8mp-hydis-hv150ux2.dts"
    I have several errors on boot:

    With this configuration I have this screen:

    Is it the reason why my screen don't work? Do you have a other DTS sample for LVDS?
    Do you think, it is  issue with my cable ?

    Thank you

  • Dear @Laurent Rouvet, The device tree "lec-imx8mp-hydis-hv150ux2.dts" is only compatible with HYDIS HV150UX2-100 18 dual panels LVDS Display. Obviously, it won't work if you are using another type of display. If possible, please let us know the details of the LVDS you're using and share the entire boot-up logs in a .txt file. This would help to clarify things.

  • I create a dtb file base the "lec-imx8mp-hydis-hv150ux2.dts" but I custome the lvds-channel@0 (on which the screen is connected).  Line 3185 I don't know what must be the value for "compatible", so I leave "hydis,hv150ux2-100" which is probably wrong!

    As you can seen on my previous message, there is several error.

    I backup the DTS and the boot logs file:

  • Hi,

    Just to inform that our previous panel was broke. 

    After replacement , we've tried many settings and the panel works well now with a compatible display provided in panel.c in the kernel . 

    compatible = "hannstar,hsd100pxn1"; 

    Also, we have to remove dual channel mode in the DTB

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