View source for Beagleboard talk:BeagleBoneBlack HDMI

I followed the instructions on this page but noticed that it didn't really mention how to make the changes permanent.

This works for my Samsung LED Monitor S24D300HL.

root@beaglebone:~# tail -n6 /etc/gdm/Init/Default
# Use xrandr!
export XAUTHORITY=`ls /var/run/gdm/auth-for-root-*/database`
export DISPLAY=:0
xrandr --output HDMI-0 --mode 1680x1050

exit 0

JohnWasinger (talk)

Append video=1680x1050 to the kernel parameters (the cmdline variable in /boot/uEnv.txt)

Matthijs (talk)

Hendersa (talk)

These issues no longer exist in recent kernels. With kernel 4.14.51-bone16, all modes I've tried (1920x1080@30, 1324x768@60, 1280x1024@60, 1152x864@75, 1024x768@60, 800x600@60, 720x480@60) worked and included audio.

If no display is connected at boot, the creation of the legacy fbdev (/dev/fb0) seems to be deferred until a display is connected. The ALSA output exists regardless, and I can send audio to the output, which is silently discarded. Once I connect my tv, the kernel automatically performs mode selection, creates the legacy fbdev, and starts sending video *and* audio to my tv. The transition appears to be invisible to the ALSA application.

Matthijs (talk)