IMX6Q dual LVDS support in X11

[zbigniewbauer]

Hi community,

It is possible to use two LVDS displays with X11 on iMX6Q sabre platform?

I did try X11 with NXP Yocto Morty release but I'm getting segmentation fault at bootup. Please see attached log file.

My platform is Sabresd iMX6Q with two LVDS display (1024x768). I'm using NXP Yocto Morty release with kernel 4.9.11-1.0.0.

Yocto build commands:
DISTRO=fsl-imx-x11 MACHINE=imx6qsabresd source fsl-setup-release.sh -b build-sabresd-x11
bitbake fsl-image-qt5

U-Boot bootargs:
mmcargs=setenv bootargs console=ttymxc0,115200 root=/dev/mmcblk2p2 rootwait rw video=mxcfb0:dev=ldb,LDB-XGA,if=RGB666 video=mxcfb1:dev=ldb,LDB-XGA,if=RGB666 video=mxcfb2:off video=mxcfb3:off ldb=sep0/1

X11 config file (/etc/X11/xorg.conf):
Section "Device"
Identifier "LVDS-1"
Driver "vivante"
Option "fbdev" "/dev/fb0"
Option "vivante_fbdev" "/dev/fb0"
Option "HWcursor" "false"
EndSection

Section "Device"
Identifier "LVDS-2"
Driver "vivante"
Option "fbdev" "/dev/fb2"
Option "vivante_fbdev" "/dev/fb2"
Option "HWcursor" "false"
EndSection

Section "Monitor"
Identifier "LVDS Monitor-1"
EndSection

Section "Monitor"
Identifier "LVDS Monitor-2"
EndSection

Section "Screen"
Identifier "LVDS Screen-1"
Monitor "LVDS Monitor-1"
Device "LVDS-1"
EndSection

Section "Screen"
Identifier "LVDS Screen-2"
Monitor "LVDS Monitor-2"
Device "LVDS-2"
EndSection

Section "ServerLayout"
Identifier "Dual Layout"
Screen 0 "LVDS Screen-1"
Screen 1 "LVDS Screen-2" RightOf "LVDS Screen-1"
Option "Xinerama" "on"
EndSection

Any help would be highly appreciated.

Thanks,
Z

[jamesbone]

Hello Z,

refer to the release note,There are two LVDS channels, LVDS0 and LVDS1, which can transfer video data.

The source for LVDS channel data is the IPUv3 display interfaces, DI0, or DI1.Dual mode means display data from DI0 or DI1 will be duplicated on LVDS0 and LVDS1.

for more detailed information, you can refer to the chapter 18 of user guide, this is for mx53, but you can refer to it.

<http://cache.nxp.com/files/32bit/doc/user_guide/MX53UG.pdf?fsrch=1&sr=7&pageNum=1>.

We have 2 distinct displays connected to lvds in separate mode.    

Here's have the dtb:

&ldb {
   lvds-channel@0 {
      crtc = "ipu1-di0";
      fsl,data-mapping = "spwg";
      fsl,data-width = <24>;
      status = "okay";
      display-timings {
      native-mode = <&timing0>;
      timing0: lcd12 {
         clock-frequency = <40000000>;
         hactive = <800>;
         vactive = <600>;
         hback-porch = <88>;
         hfront-porch = <40>;
         vback-porch = <23>;
         vfront-porch = <39>;
         hsync-len = <128>;
         vsync-len = <4>;
         bpp = <24>;
       };
      };         
   };
   lvds-channel@1 {
      crtc = "ipu1-di1";
      fsl,data-mapping = "spwg";
      fsl,data-width = <24>;
      status = "okay";
      display-timings {
      native-mode = <&timing7>;
      timing7: lcd7 {
          clock-frequency = <51206400>;
          hactive = <1024>;
          vactive = <600>;
          hback-porch = <140>;
          hfront-porch = <160>;
          vback-porch = <20>;
          vfront-porch = <12>;
          hsync-len = <20>;
          vsync-len = <3>;
       };
      };
   };
}