Closed happyme531 closed 4 months ago
well: the mere existence of /sys/devices/virtual/video4linux/video2/
shows that v4l2loopback
(or some other kernel module that provides a similar/same "virtual" interface) is loaded and working (to some extent).
i cannot currently test on a linux-5 kernel.
in any case you could try loading the module with debug=2
or some other high number to see whether it gives some additional information.
I'm experiencing this too but /sys/devices/virtual/video4linux/video2/
doesn't even exist for me.
I don't know if it's related but I have successfully loaded v4l2loopback already in the past and I removed it with modprobe -r v4l2loopback
.
@hackermondev if it doesn't exist than either
/sys/devices/virtual/video4linux/video2/
is created only if v4l2loopback
created /dev/video2
; if you only created a single device, that might as well be /sys/devices/virtual/video4linux/video0/
; or some other device, if the given video-device already exists)a more robust test would be something like:
have_v4l2loopback=no
for f in /sys/devices/virtual/video4linux/video*/name; do
if [ -e "${f}" ]; then
have_v4l2loopback=yes
break
fi
done
echo "v4l2loopback support: ${have_v4l2loopback}"
of course it always helps if you specify the
I fixed the issue, thanks for the help.
@hackermondev it would be great if you could also say how you fixed the issue
Yeah, sorry. I'm not sure 100% what fixed the issue but here's what I did:
v4l2loopback-dkms
apt module I had installed (Not sure why I installed that when I was also using it from the source)lsmod | grep v4l2loopback
v4l2loopback 49152 0
videodev 225280 1 v4l2loopback
Then, I ran sudo modprobe -r v4l2loopback
and sudo modprobe -r videodev
.
sudo make install
and sudo modprobe v4l2loopback exclusive_caps=1
I uninstalled the v4l2loopback-dkms apt module I had installed (Not sure why I installed that when I was also using it from the source)
probably because it's mentioned somewhere, that DKMS will help you with signing modules.
closing, as it has been resolved for the OP, and has become unreproducible
v4l2loopback
version: 0.12.7 (0.12.7-397-g9ba7e29)Steps to reproduce:
Observed Results:
The module loaded: (
dmesg
)but no new
/dev/videoX
created and/dev/v4l2loopback
is not exist(/dev/video0 is the platform's video device and not related to v4l2loopback)
However there are something in the /sys/devices/virtual/video4linux/
Expected Results:
The control device and video device are created for use.
Note
The kernel is Rockchip's vendor kernel. Vendor kernel is generally considered buggy so it could be actually a kernel-related issue. Kernel source is: https://github.com/armbian/linux-rockchip/tree/rk-5.10-rkr4 Used config is: https://github.com/happyme531/armbian-h88k-images/blob/master/config