i.MX8MP LVDS

[Wobaffet]

We are trying to bring up our custom board's lvds display. We are using edited version of the imx8mp-evk-jdi-wuxga-lvds-panel.dts. But we are encountering the below issue. I think it is related to the configuration. Our LVDS connections is same as the EVK but we are not using any bridge. Can you please check what are we missing, we are kind of stuck right now. Instead of pwm for the backlight we are just setting that pin to high just to see the results, voltages seems to be normal but no signal on the LVDS line and we are getting;

[FAILED] Failed to start Weston, a …mpositor, as a system service.

root@imx8mp-lpddr4-evk:~# /usr/bin/weston --backend=drm-backend.so --shell=fullscreen-shell.so --no-clients-resize
Date: 2022-11-08 UTC
[14:04:39.947] weston 11.0.1
               https://wayland.freedesktop.org
               Bug reports to: https://gitlab.freedesktop.org/wayland/weston/issues/
               Build: lf-6.1.1-1.0.0+
[14:04:39.947] Command line: /usr/bin/weston --backend=drm-backend.so --shell=fullscreen-shell.so --no-clients-resize
[14:04:39.947] OS: Linux, 6.1.1+gcc0d1d210bdd, #1 SMP PREEMPT Thu Mar  2 14:54:17 UTC 2023, aarch64
[14:04:39.947] Flight recorder: enabled
[14:04:39.947] Using config file '/etc/xdg/weston/weston.ini'
[14:04:39.947] Output repaint window is 16 ms maximum.
[14:04:39.948] Loading module '/usr/lib/libweston-11/drm-backend.so'
[14:04:39.953] initializing drm backend
[14:04:39.953] Trying logind launcher...
[14:04:39.953] logind: failed to get session seat
[14:04:39.953] logind: cannot setup systemd-logind helper error: (No data available), using legacy fallback
[14:04:39.953] fatal: your system should either provide the logind D-Bus API, or use seatd.
[14:04:39.953] fatal: failed to create compositor backend
Internal warning: debug scope 'drm-backend' has not been destroyed.

systemctl status weston.service
x weston.service - Weston, a Wayland compositor, as a system service
     Loaded: loaded (/lib/systemd/system/weston.service; enabled; preset: enabled)
     Active: failed (Result: exit-code) since Tue 2022-11-08 14:00:22 UTC; 1min 45s ago
TriggeredBy: * weston.socket
       Docs: man:weston(1)
             man:weston.ini(5)
             http://wayland.freedesktop.org/
    Process: 536 ExecStart=/usr/bin/weston --log=${XDG_RUNTIME_DIR}/weston.log --modules=systemd-notify.so (code=exited, status=1/FAILURE)
   Main PID: 536 (code=exited, status=1/FAILURE)

Nov 08 14:00:21 imx8mp-lpddr4-evk systemd[1]: Starting Weston, a Wayland compositor, as a system service...
Nov 08 14:00:21 imx8mp-lpddr4-evk systemd[536]: pam_unix(weston-autologin:session): session opened for user root(uid=0) by root(uid=0)
Nov 08 14:00:22 imx8mp-lpddr4-evk weston[536]: Internal warning: debug scope 'drm-backend' has not been destroyed.
Nov 08 14:00:22 imx8mp-lpddr4-evk systemd[1]: weston.service: Main process exited, code=exited, status=1/FAILURE
Nov 08 14:00:22 imx8mp-lpddr4-evk systemd[1]: weston.service: Failed with result 'exit-code'.
Nov 08 14:00:22 imx8mp-lpddr4-evk systemd[1]: Failed to start Weston, a Wayland compositor, as a system service.

/ {
        lvds0_panel {
                compatible = "panel-lvds";
                fsl,data-mapping="spwg";
                width-mm=<216>;
                height-mm=<135>;
                pinctrl-names = "default";
                pinctrl-0 = <&pinctrl_lvds>;
                gpio = <&gpio1 10 GPIO_ACTIVE_HIGH
                        &gpio1 11 GPIO_ACTIVE_HIGH>;
                panel-timing{
                clock-frequency=<74250000>;
                hactive=<1280>;
                vactive=<800>;
                hfront-porch=<53>;
                hback-porch=<53>;
                hsync-len=<54>;
                vfront-porch=<8>;
                vback-porch=<8>;
                vsync-len=<7>;
                de-active=<1>;
                };
                port {
                        panel_lvds_in: endpoint {
                                remote-endpoint = <&lvds_out>;
                        };
                };
        };
};
/delete-node/ &lvds_bridge;
/delete-node/ &pwm2;
/delete-node/ &lvds_backlight;
&ldb {
        status = "okay";
        lvds-channel@0 {
                status="okay";
                fsl,data-mapping = "spwg";
                /delete-node/ port@1;
                port@1 {
                        reg = <1>;
                        lvds_out: endpoint {
                                remote-endpoint = <&panel_lvds_in>;
                        };
                };
        };
};
&iomuxc{
        pinctrl_lvds:lvdsgrp {
                fsl,pins=<
                        MX8MP_IOMUXC_GPIO1_IO10__GPIO1_IO10 0x1c0
                        MX8MP_IOMUXC_GPIO1_IO11__GPIO1_IO11 0x1c0
                >;
        };
};

Thank you in advance!

Best Regards.

[brian14]

Hi @Wobaffet, 

Thank you for contacting NXP Support.

Please have a look on the following community thread. This could be useful especially to correctly set the device tree.
Solved: Re: iMX8 - Problems bringing up LVDS - NXP Community

Have a great day!