We are working with a custom board based in imx8mp. We are trying to connect two displays using LVDS. Our Linux image has been created using Yocto and the NXP layers.
In the DTB we have defined the two channels for ldb:
&ldb {
status = "okay";
lvds_channel0: lvds-channel@0 {
fsl,data-mapping = "spwg";
fsl,data-width = <24>;
status = "okay";
port@1 {
reg = <1>;
lvds_out: endpoint {
remote-endpoint = <&panel_lvds_in>;
};
};
};
lvds_channel1: lvds-channel@1 {
fsl,data-mapping = "spwg";
fsl,data-width = <24>;
status = "okay";
port@1 {
reg = <1>;
lvds_out1: endpoint {
remote-endpoint = <&panel_lvds1_in>;
};
};
};
};
After that we can detect both displays in Linux:
/sys/class/drm/card1-LVDS-1/status
/sys/class/drm/card1-LVDS-2/status
We can run weston with each display but we cannot use both at the same time.
For the main display the /etc/xdg/weston/weston.ini is:
[output]
name=LVDS-1
mode=current
[output]
name=LVDS-2
mode=off
For the second display we can change the previous file to:
[output]
name=LVDS-1
mode=off
[output]
name=LVDS-2
mode=current
But if we define both outputs in the same file we get the following error:
[04:43:51.275] launching '/usr/libexec/weston-desktop-shell'
[04:43:51.312] atomic: couldn't commit new state: Invalid argument
[04:43:51.313] repaint-flush failed: Invalid argument
If we try to set the environment variable WESTON_DISABLE_ATOMIC=Y, we get:
[04:44:40.264] launching '/usr/libexec/weston-desktop-shell'
[04:44:40.301] set mode failed: Invalid argument
[04:44:40.301] Couldn't apply state for output LVDS-2
We don't know if there is any limitation in ldb Linux driver or in Weston that doesn't allow us to use both displays at the same time.
Is our device-tree configuration for ldb correct? Can weston work with two LVDS cards?
