Camera showing black in Ubuntu 18.04 on a Lenovo L490
Emily Wong 
My camera was working fine. I have 18.04 for 2 years. I recently changed laptops and the IT department moved my ssd to a newer one. I changed from Lenovo L480 to L490
Initially the camera was working fine but for 10 days now it just shows black The camera is identified by linux it as you can see below:
localuser > lsusb
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 004: ID 5986:2113 Acer, Inc
Bus 001 Device 006: ID 8087:0025 Intel Corp.
Bus 001 Device 002: ID 046d:c52b Logitech, Inc. Unifying Receiver
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
localuser > dmesg | grep uvc
[ 3.610934] uvcvideo: Found UVC 1.00 device Integrated Camera (5986:2113)
[ 3.632137] usbcore: registered new interface driver uvcvideo
localuser > ls -ltrh /dev/video*
crw-rw----+ 1 root video 81, 1 Dec 2 16:40 /dev/video1
crw-rw----+ 1 root video 81, 0 Dec 2 16:40 /dev/video0
localuser > lspci
00:00.0 Host bridge: Intel Corporation Device 3e34 (rev 0c)
00:02.0 VGA compatible controller: Intel Corporation Device 3ea0 (rev 02)
00:04.0 Signal processing controller: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor Thermal Subsystem (rev 0c)
00:08.0 System peripheral: Intel Corporation Xeon E3-1200 v5/v6 / E3-1500 v5 / 6th/7th Gen Core Processor Gaussian Mixture Model
00:12.0 Signal processing controller: Intel Corporation Device 9df9 (rev 30)
00:14.0 USB controller: Intel Corporation Device 9ded (rev 30)
00:14.2 RAM memory: Intel Corporation Device 9def (rev 30)
00:15.0 Serial bus controller [0c80]: Intel Corporation Device 9de8 (rev 30)
00:15.2 Serial bus controller [0c80]: Intel Corporation Device 9dea (rev 30)
00:16.0 Communication controller: Intel Corporation Device 9de0 (rev 30)
00:1d.0 PCI bridge: Intel Corporation Device 9db0 (rev f0)
00:1d.3 PCI bridge: Intel Corporation Device 9db3 (rev f0)
00:1d.7 PCI bridge: Intel Corporation Device 9db7 (rev f0)
00:1f.0 ISA bridge: Intel Corporation Device 9d84 (rev 30)
00:1f.3 Audio device: Intel Corporation Device 9dc8 (rev 30)
00:1f.4 SMBus: Intel Corporation Device 9da3 (rev 30)
00:1f.5 Serial bus controller [0c80]: Intel Corporation Device 9da4 (rev 30)
00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection (6) I219-V (rev 30)
04:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd NVMe SSD Controller SM981/PM981
05:00.0 Network controller: Intel Corporation Wireless-AC 9260 (rev 29)
07:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS522A PCI Express Card Reader (rev 01)Can you help me with this? I can see the camera is identified but it displays blank on cheese
Edit 1:
After waltinator's suggestion, I've checked my user groups and I do have video in my groups so, this is not it but it's a good way of eliminating possible causes
localuser > id
uid=1000(localuser) gid=1000(localuser) groups=1000(localuser),4(adm),24(cdrom),27(sudo),30(dip),44(video),46(plugdev),116(lpadmin),126(sambashare),999(docker)2 Answers
So the problem was there is a physical switch in this laptop that switches the camera lense off.
Camera is switched on:
Camera is switched off:
The camera (/dev/video*) owner and group is [root,video], and it allows rw access for owner and group.
On your new system, you are probably not in the video group.
Use the id command to check.
Either get your IT department to add you to the video group or sudo adduser $USER video.
