Environment variables affect the touch features of LVDS display

Hello all,

I have a strange issue.

I have IMX8QM on Ixora Carrier Board V1.2 and I have connected Toradex Capacitive Touch Display 10.1" LVDS. Everything works including LVDS display and also the touch.

I need to make these changes to the environmental variables:

setenv load_cmd "ext4load mmc 0:1"
setenv loadm4image_1 "ext4load mmc 0:1 0x87000000 /ostree/deploy/torizon/var/MY_Project.bin"
setenv m4boot_1 "run loadm4image_1; dcache flush; bootaux 0x87000000 1"
setenv bootcmd "run m4boot_1; run bootcmd_mmc0"

After these changes, I can run my project, however, for some reason, the touch of the LVDS display is not working. I put back the default values to the environmental variables, and the touch works again.

Do you know why these env variables affect the touch?

If needed this is the result of the tdx-info command:

Software summary
Bootloader:               U-Boot
Kernel version:           5.4.193-5.7.2+git.b60d3160fd04 #1-TorizonCore SMP PREEMPT Fri Dec 23 15:47:24 UTC 2022
Kernel command line:      pci=nomsi root=LABEL=otaroot rootfstype=ext4 quiet logo.nologo vt.global_cursor_default=0 plymouth.ignore-serial-consoles splash fbcon=map:3 ostree=/ostree/boot.0/torizon/5e343924059c09b700803ca1ebf267b64249ec939502622cc0c4d4fc97b304c4/0
Distro name:              NAME="TorizonCore"
Distro version:           VERSION_ID=5.7.2-build.20
Hostname:                 apalis-imx8-07278691

Hardware info
HW model:                 Toradex Apalis iMX8QM V1.1 on Apalis Ixora V1.2 Carrier Board
Toradex version:          0037 V1.1E
Serial number:            07278691
Processor arch:           aarch64

Thank you in advance

The touch interface is independent of the video interface. The Toradex 10.1-inch Capacitive Touch Display with LVDS uses I2C for communication with its touch controller. It’s probable that your M4 application is interfering with this communication, resulting in the touch functionality not working