Rotate display on boot before window manager starts

Autonomous Machines Jetson & Embedded Systems Jetson Nano
1

Hi,

I am trying to rotate my hdmi screen display on boot time. It is showing in landscape instead of portrait.

  1. I tried to rotate fbcon in exlinux.conf but didn’t work
    APPEND ${cbootargs} quiet fbcon=rotate:1

I didn’t see any rotate information in cat /proc/cmdline

  1. I tried to change the nv-enable-hard-corded-kernel-boot-display-modes.sh fbcon_node hactive and vactive resolution it didn’t do anything.

How can I rotate the display without using xrandr or window manager?

2

Hi shebin,

Look into the driver
rel-32_l4t/kernel/kernel-4.9/drivers/video/console/fbcon_rotate.c

You could see the Makefile does not build it because our tegra_defconfig does not enable “CONFIG_FRAMEBUFFER_CONSOLE_ROTATION”

Please try to enable it in tegra_defconfig and rebuilt the kernel image and see if you could rotate through /sys/class/graphics/fbcon.

/sys/class/graphics/fbcon# echo 1 > rotate (you could echo any number <4 to this node. Just indicate 0/90/180/270)

  1. I tried to change the nv-enable-hard-corded-kernel-boot-display-modes.sh fbcon_node hactive and vactive resolution it didn’t do anything.

This script is not for jetson nano. You could try to change the “disp-default-out” in corresponding sor and hdmi-disp and see if it can work.

3

Hi WayneWWW,

I see two tegra_defconfig in the kernel. One for kernel-4.9 arch/arm64/configs and one in arch/arm/configs. I guess nano would use the arm and the setting CONFIG_FRAMEBUFFER_CONSOLE_ROTATION is enabled in the kernel source I downloaded. I took the kernal source form the https://developer.nvidia.com/embedded/linux-tegra Jetson nano. I have tegra 32.3.1 with l4t 4.9.140.

  1. Where is sor and hdmi-disp located? disp-default-out
4

  1. No, jetson nano is 64bit aarch64 platform so the correct one should under arm64…

  2. Please check the device tree you flashed into nano.