Re: No /dev/video0 on Pi 4 with CSI camera

From: Mark Raynsford <list+org.debian@io7m.com>
Date: Sun, 12 Jul 2020 10:27:00 +0000
Message-id: 20200712102700.60d56851@sunflower.int.arc7.info>
https://lists.debian.org/debian-arm/2020/07/msg00008.html

> I'm experimenting with a Raspberry Pi 4 Model B and can't seem to get
> V4L to expose a /dev/video0 device when using the standard CSI camera
> module. Raspbian on the same device seems to expose one correctly. I'm
> using the 20200707_raspi_4 image.

I was having similar problems with an early Pi 1, Model B+. The following exposed a /dev/video0 device for me. Maybe it works for a Pi4 too.

Installed raspi_0w image.
Added start_x=1 in /boot/firmware/config.txt
Installed v4l-utils, v4l2ucp, v4l-conf.
Installed a bunch of python stuff...
No joy.
Upgraded system to debian testing (to get the bcm2835_v4l2 module, from the staging directory).
Reboot.
Changed /boot/firmware/config.txt again, because it was overwritten during upgrade to testing: start_x=1 ; Also added gpu_mem=128 but not sure if this is needed.
Reboot
Magic! /dev/video0 now exists.
Haven't captured a picture yet, but this looks promising:
# v4l2-ctl --info
Driver Info:
Driver name : bm2835 mmal
Card type : mmal service 16.1
Bus info : platform:bcm2835-v4l2-0
Driver version : 5.9.15
Capabilities : 0x85200005
Video Capture
Video Overlay
Read/Write
Streaming
Extended Pix Format
Device Capabilities
Device Caps : 0x05200005
Video Capture
Video Overlay
Read/Write
Streaming
Extended Pix Format

> I'd prefer not to have to run Raspbian on the device.

Me too! :)