No Composite Video 3B+ / Pi OS 6.1.27

[phuz]

Hey,
Trying to get the analog video output to work.
I bought the Adafruit composite cable so the rings are correct (and I ohm'd them to verify).
I modified the config.txt as follows:
#hdmi_force_hotplug=1
hdmi_ignore_hotplug=1
I'm using a 5V / 3A adapter.

When I boot the Pi with the analog connected to a TV, the only video I get is the splash screen during boot. Beyond that, I don't get a desktop. When I use HDMI, it's fine. What else am I missing?

[FTrevorGowen]

Hey,
Trying to get the analog video output to work.
I bought the Adafruit composite cable so the rings are correct (and I ohm'd them to verify).
I modified the config.txt as follows:
#hdmi_force_hotplug=1
hdmi_ignore_hotplug=1
I'm using a 5V / 3A adapter.

When I boot the Pi with the analog connected to a TV, the only video I get is the splash screen during boot. Beyond that, I don't get a desktop. When I use HDMI, it's fine. What else am I missing?

What O.S. are you using? IIRC composite video is enabled in Raspberry PiOS "Bullseye" in a different manner to "Buster" etc.
[Edit] W/o checking I'm not sure what "Pi OS 6.1.27" is based upon (ie. older than the current "Bullseye")
[2nd. Edit] Legacy "Buster" on the P400 I'm posting from reports "Linux raspiP400gPiOS64 5.10.103-v8+ #1529 SMP PREEMPT Tue Mar 8 12:26:46 GMT 2022 aarch64 GNU/Linux" which suggests you are using "Bullseye".
Posting the output of these commands should prove informative:

Code: Select all

uname -a
cat /etc/os-release

[Yet another Edit] A forum search found this: viewtopic.php?p=2067514&hilit=bullseye+ ... o#p2068410 !
Trev.

[phuz]

Yes, it's bullseye (May 2023 release).

I used the raspi-config to set the desktop environment to start at bootup and now I get an image when it boots, so that hurdle is behind me. However, it's off the screen on all four corners regardless of overscan settings (which seem to do nothing) and toggling the underscan setting on/off, rebooting, etc.
I've tried cycling all four viewing modes on the TV (side bar, zoom, stretch, super-stretch).

[phuz]

Edit /boot/config.txt

Find the "dtoverlay=vc4-kms-v3d" line.

Add ",composite" to the end i.e. "dtoverlay=vc4-kms-v3d,composite"

That line is already set.

[cleverca22]

However, it's off the screen on all four corners regardless of overscan settings (which seem to do nothing) and toggling the underscan setting on/off, rebooting, etc.

that would be the overscan settings on the rpi
i'm not sure where they are hidden under the kms driver

[FTrevorGowen]

However, it's off the screen on all four corners regardless of overscan settings (which seem to do nothing) and toggling the underscan setting on/off, rebooting, etc.

that would be the overscan settings on the rpi
i'm not sure where they are hidden under the kms driver

IIRC, like some other things under kms they're set via the command line (kernel options).
Trev.

[rpdom]

However, it's off the screen on all four corners regardless of overscan settings (which seem to do nothing) and toggling the underscan setting on/off, rebooting, etc.

that would be the overscan settings on the rpi
i'm not sure where they are hidden under the kms driver

Looking in raspi-config there's a couple of different ways depending on if using mutter or not. It seems to use xrandr with --set "xxx margin" $pixels, where xxx is top, right, left and bottom, and addd those options to /usr/share/ovscsetup.sh, creating it if not already there.

Probably the easiest way is just to set it in raspi-config.