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| --- | ||
| categories: tips | ||
| date: 2024-09-23 11:30:00 +0200 | ||
| excerpt: > | ||
| Yesterday Ubuntu saw the webcam, today it doesn't. | ||
| I'm looking for the cause of the problem. | ||
| lang: en | ||
| layout: post | ||
| title: Problem with camera in Ubuntu | ||
| --- | ||
|
|
||
| I'm writing this post from the perspective of an Ubuntu user. | ||
| It is meant to help me solve a camera issue more easily in the future. | ||
| I don't want to do the research again, so I decided to publish my notes. | ||
| 🗒️ | ||
|
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| Hopefully, someone else will also find this content useful. | ||
|
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||
| ---- | ||
|
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| The camera works on my laptop. | ||
| The issue occurs on Agnieszka's laptop. | ||
| BTW, I recommend her [blog Woman on Rails](https://womanonrails.com). | ||
| She doesn't have access to the camera. | ||
| 🚫 | ||
| 🎥 | ||
|
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| The simplest solution: **restart your computer**. | ||
| 🚀 | ||
|
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| Sometimes, hardware-related issues like this | ||
| can be resolved simply by rebooting the system, | ||
| 🔌 | ||
| as it forces the OS to reinitialize device drivers. | ||
|
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||
| TL;DR | ||
|
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||
| --- | ||
|
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| In Linux, devices are represented as files. | ||
| The camera should appear under the path `/dev/video0`. | ||
|
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||
| ```console | ||
| $ sudo ls -l /dev/video* | ||
| ls: cannot access '/dev/video*': No such file or directory | ||
| ``` | ||
|
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| On my laptop, the same command looks like this: | ||
|
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||
| ``` | ||
| $ sudo ls -l /dev/video* | ||
| crw-rw----+ 1 root video 81, 0 /dev/video0 | ||
| crw-rw----+ 1 root video 81, 1 /dev/video1 | ||
| ``` | ||
|
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||
| Ensure the user is part of the `video` group to access camera devices. | ||
| Permissions may be granted directly (the user belongs to the video group) | ||
| or indirectly (the user belongs to a group with higher access). | ||
| The `groups` command will help you check | ||
| which groups your user is directly assigned to. | ||
|
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| Ubuntu has tools to manage video from the command line. | ||
| The package is called [v4l-utils](https://linuxtv.org/wiki/index.php/V4l-utils) | ||
| and it can be easily installed using apt. | ||
| The `v4l-utils` is a collection of command-line tools | ||
| that allow you to manage and troubleshoot video devices in Linux. | ||
|
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| I installed this package on both computers. | ||
| 🔧 | ||
|
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| ```console | ||
| $ sudo apt install v4l-utils | ||
| Reading package lists... Done | ||
| Building dependency tree... Done | ||
| Reading state information... Done | ||
| The following additional packages will be installed: | ||
| libv4l2rds0 | ||
| The following NEW packages will be installed: | ||
| libv4l2rds0 v4l-utils | ||
| 0 upgraded, 2 newly installed, 0 to remove and 0 not upgraded. | ||
| ... | ||
| ``` | ||
|
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| On the problematic laptop, I ran the following command: | ||
|
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||
| ```console | ||
| $ sudo v4l2-ctl --list-devices -D | ||
| Cannot open device /dev/video0, exiting. | ||
| ``` | ||
|
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| For comparison, I ran the same command on my laptop: | ||
|
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| ```console | ||
| $ sudo v4l2-ctl --list-devices -D | ||
| USB2.0 HD UVC WebCam: USB2.0 HD (usb-0000:00:14.0-5): | ||
| /dev/video0 | ||
| /dev/video1 | ||
| /dev/media0 | ||
|
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||
| Driver Info: | ||
| Driver name : uvcvideo | ||
| Card type : USB2.0 HD UVC WebCam: USB2.0 HD | ||
| Bus info : usb-0000:00:14.0-5 | ||
| Driver version : 6.8.12 | ||
| Capabilities : 0x84a00001 | ||
| Video Capture | ||
| Metadata Capture | ||
| Streaming | ||
| Extended Pix Format | ||
| Device Capabilities | ||
| Device Caps : 0x04200001 | ||
| Video Capture | ||
| Streaming | ||
| Extended Pix Format | ||
| Media Driver Info: | ||
| Driver name : uvcvideo | ||
| Model : USB2.0 HD UVC WebCam: USB2.0 HD | ||
| Serial : 0x0001 | ||
| Bus info : usb-0000:00:14.0-5 | ||
| Media version : 6.8.12 | ||
| Hardware revision: 0x00005828 (22568) | ||
| Driver version : 6.8.12 | ||
| Interface Info: | ||
| ID : 0x03000002 | ||
| Type : V4L Video | ||
| Entity Info: | ||
| ID : 0x00000001 (1) | ||
| Name : USB2.0 HD UVC WebCam: USB2.0 HD | ||
| Function : V4L2 I/O | ||
| Flags : default | ||
| Pad 0x01000007 : 0: Sink | ||
| Link 0x02000010: from remote pad 0x100000a of entity 'Extension 4' (Video Pixel Formatter): Data, Enabled, Immutable | ||
| ``` | ||
|
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| The system is up to date. | ||
| The laptop is not damaged. | ||
|
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| The only solution that comes to mind is a restart. | ||
| 🔄 | ||
| After restarting the laptop, the camera starts working. | ||
|
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| I reused the previous commands and this time the result was different: | ||
|
|
||
| ```console | ||
| $ sudo ls -l /dev/video* | ||
| crw-rw----+ 1 root video 81, 0 /dev/video0 | ||
| crw-rw----+ 1 root video 81, 1 /dev/video1 | ||
| crw-rw----+ 1 root video 81, 2 /dev/video2 | ||
| crw-rw----+ 1 root video 81, 3 /dev/video3 | ||
| ``` | ||
|
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||
| ```console | ||
| $ sudo v4l2-ctl --list-devices -D | ||
| Chicony USB2.0 Camera: Chicony (usb-0000:00:14.0-7): | ||
| /dev/video0 | ||
| /dev/video1 | ||
| /dev/video2 | ||
| /dev/video3 | ||
| /dev/media0 | ||
| /dev/media1 | ||
|
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||
| Driver Info: | ||
| Driver name : uvcvideo | ||
| Card type : Chicony USB2.0 Camera: Chicony | ||
| Bus info : usb-0000:00:14.0-7 | ||
| Driver version : 6.2.16 | ||
| Capabilities : 0x84a00001 | ||
| Video Capture | ||
| Metadata Capture | ||
| Streaming | ||
| Extended Pix Format | ||
| Device Capabilities | ||
| Device Caps : 0x04200001 | ||
| Video Capture | ||
| Streaming | ||
| Extended Pix Format | ||
| Media Driver Info: | ||
| Driver name : uvcvideo | ||
| Model : Chicony USB2.0 Camera: Chicony | ||
| Serial : 01.00.00 | ||
| Bus info : usb-0000:00:14.0-7 | ||
| Media version : 6.2.16 | ||
| Hardware revision: 0x00000002 (2) | ||
| Driver version : 6.2.16 | ||
| Interface Info: | ||
| ID : 0x03000002 | ||
| Type : V4L Video | ||
| Entity Info: | ||
| ID : 0x00000001 (1) | ||
| Name : Chicony USB2.0 Camera: Chicony | ||
| Function : V4L2 I/O | ||
| Flags : default | ||
| Pad 0x01000007 : 0: Sink | ||
| Link 0x02000013: from remote pad 0x100000a of entity 'Extension 4' (Video Pixel Formatter): Data, Enabled, Immutable | ||
| ``` | ||
|
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| It looks like a **restart** did the trick. | ||
| The cause of the issue is unknown, | ||
| but I will monitor if the problem occurs again. | ||
|
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| If the issue persists, | ||
| I will check the system logs with `dmesg | grep video` | ||
| or `journalctl -xe` might provide more insight. | ||
|
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| So far I don't see anything disturbing: | ||
|
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| ```console | ||
| $ sudo dmesg | grep video | ||
| [ 3.097705] videodev: Linux video capture interface: v2.00 | ||
| [ 3.211353] usbcore: registered new interface driver uvcvideo | ||
| [ 4.791222] ACPI: video: Video Device [GFX0] (multi-head: yes rom: no post: no) | ||
| ``` | ||
|
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| However, deeper research allowed me to better understand | ||
| the possible causes of the problems. | ||
| Common reasons for camera issues in Ubuntu include missing drivers, | ||
| conflicts with other software, | ||
| or power management settings disabling the camera. | ||
|
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| This guide should help you troubleshoot basic camera issues in Ubuntu. | ||
| Hopefully, it saves you some time and frustration! | ||
| 😄 |