libcamera-hello: ERROR: *** no cameras available ***

[Bluemethyst]

Hey! i am trying to view my Pi Zero W 2's connected camera via a web browser with python and i got it working yesterday but when i booted up the Pi this morning the camera is no longer detected by libcamera-hello or any other means. I tried putting an SD card into it that has MotionEyeOS on it and that worked perfectly, first try. Its weird to me that it was working perfectly fine yesterday but this morning, nothing! ive done about an hour of googling and cant find any solutions that work for me, i tried this command

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vcgencmd get_camera

and it gave this output which is worrying:

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supported=0 detected=0, libcamera interfaces=0

. Any help would be amazing thanks!

Edit: when running libcamera-hello with sudo like so:

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sudo libcamera-hello

it works perfectly fine... any reason why? and i still cant get it to work with python...

[redvli]

Can be something wrong with the flatcable.

MotionEyeOS maybe using the old/legacy camera stack, that is something different, has different timing etc. I have had several cases where the old stack works and new libcamera base does not work. Especially flat-cable length was/can be an issue.

But update your OS to latest Bookworm state, so run

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sudo apt update && apt full-upgrade

You should then run it via new name:

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sudo rpicam-hello

Version should be v0.3.1+50-69a894c4

I just ran it via a serial console CLI on a Pi3 64-bit OS with long 2 meter cable, it works, but it is slow in starting up, very slow on Pi1 and Pi0, count 10 seconds or more.

[redvli]

When old / legacy stack is enabled via config.txt (start_x=1), you should get:

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# vcgencmd get_camera
supported=1 detected=1, libcamera interfaces=0

[6by9]

Edit: when running libcamera-hello with sudo like so:

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sudo libcamera-hello

it works perfectly fine... any reason why? and i still cant get it to work with python...

That implies that something has got messed up with permissions.
Did you upgrade via apt or similar? (Doing so shouldn't break anything, but is a change).

[redvli]

That implies that something has got messed up with permissions.
Did you upgrade via apt or similar? (Doing so shouldn't break anything, but is a change).

Indeed, I did not catch the root v.s. non-root issue, as I usually run as root doing this kind of setups/administration/testing. So just for the topic, I insert 'sudo' as most people use unmodified RPIOS I guess.

But as normal user rpicam-hello also works fine on my old from-buster-upgraded-Pi3B

[Bluemethyst]

Thanks guys, ive tried pretty much everything here except the config.txt change? can you tell me more about that? nothing has worked unfortunately, if nothing else fixes it ig ill just reinstall the os?
a full log of the command output is below:

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admin@picam:~ $ rpicam-hello
Could not open any dmaHeap device
[0:05:13.870697069] [1591]  INFO Camera camera_manager.cpp:316 libcamera v0.3.1+50-69a894c4
[0:05:13.905379190] [1595] ERROR DmaBufAllocator dma_buf_allocator.cpp:116 Could not open any dma-buf provider
[0:05:13.938966830] [1595]  WARN RPiSdn sdn.cpp:40 Using legacy SDN tuning - please consider moving SDN inside rpi.denoise
[0:05:13.943645741] [1595] ERROR RPI vc4.cpp:216 Failed to register camera imx477 10-001a: -12
Preview window unavailable
ERROR: *** no cameras available ***

when run with sudo:

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admin@picam:~ $ sudo rpicam-hello
[0:05:07.583339606] [1578]  INFO Camera camera_manager.cpp:316 libcamera v0.3.1+      50-69a894c4
[0:05:07.693058787] [1583]  WARN RPiSdn sdn.cpp:40 Using legacy SDN tuning - ple      ase consider moving SDN inside rpi.denoise
[0:05:07.699284835] [1583]  INFO RPI vc4.cpp:447 Registered camera /base/soc/i2c      0mux/i2c@1/imx477@1a to Unicam device /dev/media0 and ISP device /dev/media1
[0:05:07.699442856] [1583]  INFO RPI pipeline_base.cpp:1125 Using configuration       file '/usr/share/libcamera/pipeline/rpi/vc4/rpi_apps.yaml'
Preview window unavailable
Mode selection for 2028:1520:12:P
    SRGGB10_CSI2P,1332x990/0 - Score: 3456.22
    SRGGB12_CSI2P,2028x1080/0 - Score: 1083.84
    SRGGB12_CSI2P,2028x1520/0 - Score: 0
    SRGGB12_CSI2P,4056x3040/0 - Score: 887
[0:05:07.704570779] [1578]  INFO Camera camera.cpp:1191 configuring streams: (0)       2028x1520-YUV420 (1) 2028x1520-SBGGR12_CSI2P
[0:05:07.705300206] [1583]  INFO RPI vc4.cpp:622 Sensor: /base/soc/i2c0mux/i2c@1      /imx477@1a - Selected sensor format: 2028x1520-SBGGR12_1X12 - Selected unicam fo      rmat: 2028x1520-pBCC
#0 (0.00 fps) exp 15303.00 ag 2.00 dg 1.00
#1 (30.01 fps) exp 15303.00 ag 2.00 dg 1.02
#2 (30.01 fps) exp 15303.00 ag 2.00 dg 1.02
#3 (30.01 fps) exp 15303.00 ag 2.00 dg 1.02
etc, etc....

[redvli]

Things with permissions can keep you busy for a long time is my experience, so up to you what you do. I usually go back to older snapshot backup, and/or do compare with parallel new installation. Maybe you are fine with running as root if it is just a remote headless Pi without microphone.
This is brand new software on stable Debian Bookworm so maybe use more logging/debugging options by default, that is what I usually do for new software (versions younger than 1 years or so).

[6by9]

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Could not open any dmaHeap device

So it's the permissions on /dev/dma_heap/* that has gone wrong.

[Bluemethyst]

Im not sure what the issue was in the end, i reinstalled the RaspberryPiOS Lite 64bit on the SD card and it works again.