DART-6UL/VAR-SOM-MX7 Display
LVDS boot arguments
Resistive/Capacitive alternate screen
Variscite expand the default display settings to support alternate display without any requirement to change the device tree. During the boot sequence Variscite u-boot will add screen_alternate=yes option to enable selection of the second display settings (capacitive display).
For example:
U-Boot # printenv mmcargs mmcargs=setenv bootargs console=${console},${baudrate} ${smp} video=mxcfb1:off root=${mmcroot} screen_alternate=yes
The developer can prevent the modification of u-boot by settings var_auto_fdt_file=N.
U-Boot # setenv var_auto_fdt_file=N
Switching to LVDS1 as main display
Switching to LVDS1 display requires changing the "primary" of the lvds section flag in the device tree. Setting display to be LVDS1 by default: edit arch/arm/boot/dts/imx6qdl-var-som.dtsi and set section of the lvds1. When you set the "primary" property to the LVDS1 struct, make sure you remove it from the LVDS0 struct
- lvds-channel@1 {
- fsl,data-mapping = "spwg";
- fsl,data-width = <18>;
- crtc = "ipu1-di1";
- primary;
- fsl,data-mapping = "spwg";
- status = "okay";
- display-timings {
- native-mode = <&timing1>;
- timing1: hsd100pxn1 {
- clock-frequency = <35714000>;
- hactive = <800>;
- vactive = <480>;
- hback-porch = <28>;
- hfront-porch = <17>;
- vback-porch = <13>;
- vfront-porch = <20>;
- hsync-len = <20>;
- vsync-len = <13>;
- clock-frequency = <35714000>;
- };
- native-mode = <&timing1>;
- };
- display-timings {
- };
Please take a look on the wiki section for kernel out of tree to see how to compile the device tree.