Display not working with Toradex Easy Installer TEZI

I currently have a setup, where I update the Apalis Module with Toradex Easy Installer booted from USB Stick with an Image (custom, built with yocto) also residing on this stick. The update procedure itself works great with TEZI, but I can’t get the display to work (currently I have to monitor the progress with VNC/RDP).

The display is connected through 24-bit RGB.

I created a custom boot.cmd and compiled a boot.scr as described in the knowledge base:

setenv bootargs console=ttymxc0,115200 quiet video=mxcfb0:dev=lcd,FusionF07A,if=RGB24 rootfstype=squashfs root=/dev/ram autoinstall fullscreen ${teziargs}

# Reenable fdt relocation since in place fdt edits corrupt the ramdisk
# in a FIT image...
setenv fdt_high

# Load FIT image from location as detected by distroboot
load ${devtype} ${devnum}:${distro_bootpart} ${ramdisk_addr_r} ${prefix}tezi.itb

bootm ${ramdisk_addr_r}

In normal operation, once the image is installed, the module and display works with these vidargs:

vidargs 'video=mxcfb0:dev=lcd,FusionF07A,if=RGB24 video=mxcfb1:off video=mxcfb2:off video=mxcfb3:off fbmem=32M bpp=32'

The image built with yocto specifies a custom device tree and also has these working u-boot env variables set.

  1. What is wrong with my boot.scr? I tried a couple of different video settings, but same result. The display does seem to be totally black ie backlight not enabled, so it might actually be a backlight problem rather than the video output. My device tree sets a 10kHz backlight PWM freq. and polarity “0”.

    pwms = <&pwm4 0 100000 0>;

  2. Where does TEZI get the device tree from? Can I load or set my custom device tree to get the my PWM settings?

2a) Can TEZI load a linux kernel module for Touchscreen support? My custom device driver is built into the linux-kernel.

Any help is appreciated!

Hi mg.ax! TEZI uses our standard device tree for the apalis imx6 evaluation board (imx6qdl-apalis-eval.dts in linux-toradex). We use a 200Hz backlight, which most likely doesn’t work in your screen. In order to change it for TEZI, you can unpack the tezi.itb file with the mkimage utility and repack it with your custom device tree. As a quick fix you can also “disassemble” our device tree with dtc and modify the pwm value by hand, then recompile it and repack everything into the tezi.itb again. You can look up our model for tezi.its from the meta-toarex-tezi layer in https://github.com/toradex/meta-toradex-tezi to guide you in the process. Let us know how it works out!

Thanks for this information!

I was able to unpack the tezi.itb with dumpimage:

dumpimage -T flat_dt -i tezi.itb -p 0 kernel
dumpimage -T flat_dt -i tezi.itb -p 1 ramdisk

Then edited the tezi.its to point to the extracted kernel, ramdisk and my device-tree.
I repacked the tezi.itb with

mkimage -f tezi.its tezi.itb

Displays now works. :slight_smile:

Perfect that it works. Thanks for the feedback.