1

So, I have a webcam. And its LEDs are always on. This is a right pain; is there any way I can toggle those LEDs myself from the terminal? (The single button on the device itself does not toggle the LEDs). Here's the relevant information from lsusb -v:

Bus 002 Device 005: ID 058f:3863 Alcor Micro Corp. USB 2.0 PC Camera
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass          239 Miscellaneous Device
  bDeviceSubClass         2 
  bDeviceProtocol         1 Interface Association
  bMaxPacketSize0        64
  idVendor           0x058f Alcor Micro Corp.
  idProduct          0x3863 
  bcdDevice            0.01
  iManufacturer           1 Alcor Micro, Corp.
  iProduct                2 USB 2.0 PC Camera
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x02d4
    bNumInterfaces          4
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0x80
      (Bus Powered)
    MaxPower              500mA
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         0
      bInterfaceCount         2
      bFunctionClass         14 Video
      bFunctionSubClass       3 Video Interface Collection
      bFunctionProtocol       0 
      iFunction               4 PC Camera
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      1 Video Control
      bInterfaceProtocol      0 
      iInterface              4 PC Camera
      VideoControl Interface Descriptor:
        bLength                13
        bDescriptorType        36
        bDescriptorSubtype      1 (HEADER)
        bcdUVC               1.00
        wTotalLength       0x004f
        dwClockFrequency       30.000000MHz
        bInCollection           1
        baInterfaceNr( 0)       1
      VideoControl Interface Descriptor:
        bLength                28
        bDescriptorType        36
        bDescriptorSubtype      6 (EXTENSION_UNIT)
        bUnitID                 6
        guidExtensionCode         {68bbd0b0-61a4-4b83-90b7-a6215f3c4f70}
        bNumControl            24
        bNrPins                 1
        baSourceID( 0)          2
        bControlSize            3
        bmControls( 0)       0xff
        bmControls( 1)       0xff
        bmControls( 2)       0xff
        iExtension              0 
      VideoControl Interface Descriptor:
        bLength                18
        bDescriptorType        36
        bDescriptorSubtype      2 (INPUT_TERMINAL)
        bTerminalID             1
        wTerminalType      0x0201 Camera Sensor
        bAssocTerminal          0
        iTerminal               0 
        wObjectiveFocalLengthMin      0
        wObjectiveFocalLengthMax      0
        wOcularFocalLength            0
        bControlSize                  3
        bmControls           0x00000000
      VideoControl Interface Descriptor:
        bLength                11
        bDescriptorType        36
        bDescriptorSubtype      5 (PROCESSING_UNIT)
      Warning: Descriptor too short
        bUnitID                 2
        bSourceID               1
        wMaxMultiplier          0
        bControlSize            2
        bmControls     0x0000157f
          Brightness
          Contrast
          Hue
          Saturation
          Sharpness
          Gamma
          White Balance Temperature
          Backlight Compensation
          Power Line Frequency
          White Balance Temperature, Auto
        iProcessing             0 
        bmVideoStandards     0x09
          None
          SECAM - 625/50
      VideoControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID             3
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          0
        bSourceID               2
        iTerminal               0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0010  1x 16 bytes
        bInterval               7
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              4 PC Camera
      VideoStreaming Interface Descriptor:
        bLength                            15
        bDescriptorType                    36
        bDescriptorSubtype                  1 (INPUT_HEADER)
        bNumFormats                         2
        wTotalLength                   0x0191
        bEndPointAddress                  130
        bmInfo                              0
        bTerminalLink                       3
        bStillCaptureMethod                 2
        bTriggerSupport                     1
        bTriggerUsage                       0
        bControlSize                        1
        bmaControls( 0)                     0
        bmaControls( 1)                     0
      VideoStreaming Interface Descriptor:
        bLength                            11
        bDescriptorType                    36
        bDescriptorSubtype                  6 (FORMAT_MJPEG)
        bFormatIndex                        1
        bNumFrameDescriptors                2
        bFlags                              1
          Fixed-size samples: Yes
        bDefaultFrameIndex                  1
        bAspectRatioX                       0
        bAspectRatioY                       0
        bmInterlaceFlags                 0x00
          Interlaced stream or variable: No
          Fields per frame: 1 fields
          Field 1 first: No
          Field pattern: Field 1 only
        bCopyProtect                        0
      VideoStreaming Interface Descriptor:
        bLength                            50
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         1
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                           1280
        wHeight                           720
        dwMinBitRate                110592000
        dwMaxBitRate                663552000
        dwMaxVideoFrameBufferSize     2764800
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  6
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            400000
        dwFrameInterval( 2)            500000
        dwFrameInterval( 3)            666666
        dwFrameInterval( 4)           1000000
        dwFrameInterval( 5)           2000000
      VideoStreaming Interface Descriptor:
        bLength                            50
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         2
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                            640
        wHeight                           480
        dwMinBitRate                 36864000
        dwMaxBitRate                221184000
        dwMaxVideoFrameBufferSize      921600
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  6
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            400000
        dwFrameInterval( 2)            500000
        dwFrameInterval( 3)            666666
        dwFrameInterval( 4)           1000000
        dwFrameInterval( 5)           2000000
      VideoStreaming Interface Descriptor:
        bLength                            14
        bDescriptorType                    36
        bDescriptorSubtype                  3 (STILL_IMAGE_FRAME)
        bEndpointAddress                    0
        bNumImageSizePatterns               2
        wWidth( 0)                       1280
        wHeight( 0)                       720
        wWidth( 1)                        640
        wHeight( 1)                       480
        bNumCompressionPatterns             0
      VideoStreaming Interface Descriptor:
        bLength                             6
        bDescriptorType                    36
        bDescriptorSubtype                 13 (COLORFORMAT)
        bColorPrimaries                     1 (BT.709,sRGB)
        bTransferCharacteristics            1 (BT.709)
        bMatrixCoefficients                 4 (SMPTE 170M (BT.601))
      VideoStreaming Interface Descriptor:
        bLength                            27
        bDescriptorType                    36
        bDescriptorSubtype                  4 (FORMAT_UNCOMPRESSED)
        bFormatIndex                        2
        bNumFrameDescriptors                4
        guidFormat                            {32595559-0000-0010-8000-00aa00389b71}
        bBitsPerPixel                      16
        bDefaultFrameIndex                  1
        bAspectRatioX                       0
        bAspectRatioY                       0
        bmInterlaceFlags                 0x00
          Interlaced stream or variable: No
          Fields per frame: 2 fields
          Field 1 first: No
          Field pattern: Field 1 only
        bCopyProtect                        0
      VideoStreaming Interface Descriptor:
        bLength                            50
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         1
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                           1280
        wHeight                           720
        dwMinBitRate                 73728000
        dwMaxBitRate                442368000
        dwMaxVideoFrameBufferSize     1843200
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  6
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            400000
        dwFrameInterval( 2)            500000
        dwFrameInterval( 3)            666666
        dwFrameInterval( 4)           1000000
        dwFrameInterval( 5)           2000000
      VideoStreaming Interface Descriptor:
        bLength                            50
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         2
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                            640
        wHeight                           480
        dwMinBitRate                 24576000
        dwMaxBitRate                147456000
        dwMaxVideoFrameBufferSize      614400
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  6
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            400000
        dwFrameInterval( 2)            500000
        dwFrameInterval( 3)            666666
        dwFrameInterval( 4)           1000000
        dwFrameInterval( 5)           2000000
      VideoStreaming Interface Descriptor:
        bLength                            50
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         3
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                            352
        wHeight                           288
        dwMinBitRate                  8110080
        dwMaxBitRate                 48660480
        dwMaxVideoFrameBufferSize      202752
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  6
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            400000
        dwFrameInterval( 2)            500000
        dwFrameInterval( 3)            666666
        dwFrameInterval( 4)           1000000
        dwFrameInterval( 5)           2000000
      VideoStreaming Interface Descriptor:
        bLength                            50
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         4
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                            320
        wHeight                           240
        dwMinBitRate                  6144000
        dwMaxBitRate                 36864000
        dwMaxVideoFrameBufferSize      153600
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  6
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            400000
        dwFrameInterval( 2)            500000
        dwFrameInterval( 3)            666666
        dwFrameInterval( 4)           1000000
        dwFrameInterval( 5)           2000000
      VideoStreaming Interface Descriptor:
        bLength                            22
        bDescriptorType                    36
        bDescriptorSubtype                  3 (STILL_IMAGE_FRAME)
        bEndpointAddress                    0
        bNumImageSizePatterns               4
        wWidth( 0)                       1280
        wHeight( 0)                       720
        wWidth( 1)                        640
        wHeight( 1)                       480
        wWidth( 2)                        352
        wHeight( 2)                       288
        wWidth( 3)                        320
        wHeight( 3)                       240
        bNumCompressionPatterns             0
      VideoStreaming Interface Descriptor:
        bLength                             6
        bDescriptorType                    36
        bDescriptorSubtype                 13 (COLORFORMAT)
        bColorPrimaries                     1 (BT.709,sRGB)
        bTransferCharacteristics            1 (BT.709)
        bMatrixCoefficients                 4 (SMPTE 170M (BT.601))
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       1
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              4 PC Camera
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x1400  3x 1024 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       2
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              4 PC Camera
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0c00  2x 1024 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       3
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              4 PC Camera
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0400  1x 1024 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       4
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              4 PC Camera
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               1
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         2
      bInterfaceCount         2
      bFunctionClass          1 Audio
      bFunctionSubClass       0 
      bFunctionProtocol       0 
      iFunction               5 Magic Sound
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      1 Control Device
      bInterfaceProtocol      0 
      iInterface              5 Magic Sound
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      1 (HEADER)
        bcdADC               1.00
        wTotalLength       0x002b
        bInCollection           1
        baInterfaceNr(0)        3
      AudioControl Interface Descriptor:
        bLength                12
        bDescriptorType        36
        bDescriptorSubtype      2 (INPUT_TERMINAL)
        bTerminalID             1
        wTerminalType      0x0201 Microphone
        bAssocTerminal          0
        bNrChannels             2
        wChannelConfig     0x0003
          Left Front (L)
          Right Front (R)
        iChannelNames           0 
        iTerminal               0 
      AudioControl Interface Descriptor:
        bLength                13
        bDescriptorType        36
        bDescriptorSubtype      6 (FEATURE_UNIT)
        bUnitID                 5
        bSourceID               1
        bControlSize            2
        bmaControls(0)     0x0001
          Mute Control
        bmaControls(1)     0x0003
          Mute Control
          Volume Control
        bmaControls(2)     0x0003
          Mute Control
          Volume Control
        iFeature                0 
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID             3
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          0
        bSourceID               5
        iTerminal               0 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        3
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              5 Magic Sound
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        3
      bAlternateSetting       1
      bNumEndpoints           1
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              5 Magic Sound
      AudioStreaming Interface Descriptor:
        bLength                 7
        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           3
        bDelay                  1 frames
        wFormatTag         0x0001 PCM
      AudioStreaming Interface Descriptor:
        bLength                32
        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
        bNrChannels             1
        bSubframeSize           2
        bBitResolution         16
        bSamFreqType            8 Discrete
        tSamFreq[ 0]        48000
        tSamFreq[ 1]        44100
        tSamFreq[ 2]        24000
        tSamFreq[ 3]        22050
        tSamFreq[ 4]        16000
        tSamFreq[ 5]        12000
        tSamFreq[ 6]        11025
        tSamFreq[ 7]         8000
      Endpoint Descriptor:
        bLength                 9
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes           13
          Transfer Type            Isochronous
          Synch Type               Synchronous
          Usage Type               Data
        wMaxPacketSize     0x0064  1x 100 bytes
        bInterval               4
        bRefresh                0
        bSynchAddress           0
        AudioStreaming Endpoint Descriptor:
          bLength                 7
          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x01
            Sampling Frequency
          bLockDelayUnits         1 Milliseconds
          wLockDelay         0x0000
Device Qualifier (for other device speed):
  bLength                10
  bDescriptorType         6
  bcdUSB               2.00
  bDeviceClass          239 Miscellaneous Device
  bDeviceSubClass         2 
  bDeviceProtocol         1 Interface Association
  bMaxPacketSize0        64
  bNumConfigurations      1
can't get debug descriptor: Resource temporarily unavailable
Device Status:     0x0000
  (Bus Powered)
6
  • 1
    This is a bit low tech but try a bit of tape first to cover the led.
    – laktak
    Commented Oct 7, 2020 at 12:10
  • @laktak That's my backup solution, and my high-tech backup will be soldering a switch on if I can manage it in the right place. Would just be a fair bit easier (and useful) to be able to toggle it from my PC Commented Oct 7, 2020 at 12:15
  • 1
    Does the LED turn on as soon as your switch your PC on, or it only lights up when you log in? If it's the latter, maybe you have some applications constantly using it? Maybe you can disable them? Commented Oct 7, 2020 at 15:52
  • @ArtemS.Tashkinov It turns on as soon as the PC is switched on, I'm afraid Commented Oct 12, 2020 at 13:02
  • You could try disassembling it and disconnecting the cable connecting to the LED. Commented Oct 12, 2020 at 13:51

2 Answers 2

4

I know this is bit old , but turns out i got a Logitech C925e webcam and that green LED disturbs me. I found a way to turn off the LED for this specific model and i believe this can be used for other models that support changing the status of the LED.

For this, i am using v4l2-ctl, and this works even if the camera is still being used already by an application (tested using ffplay and Google Meet).

In Debian/Ubuntu versions you can install this through v4l-utils package:

sudo apt-get install v4l-utils

To turn off the webcam LED you can then run:

v4l2-ctl -d /dev/videoX -c led1_mode=0

Where /dev/videoX is the path for your webcam device (in my case it was /dev/video3). This command basically sets ("-c" param) the value of the control "led1_mode" to 0 (zero, which means Off). Here's a table with the values/modes for this specific model of webcam:

 0 : off
 1 : on
 2 : blink
 3 : Auto

Using this with a different hardware

For a different hardware, you can also check if this supports changing the status of the LED by listing all the controls of your device. For that, you can use this command:

v4l2-ctl -d /dev/videoX -l

Here you probably needs to search for a line with "led" (or something similar). The first column of the output contains the name of the control that must be passed in the "-c" param. I am not really sure if different/brand models will use the same "led1_mode" control name for the LED, but if you find a LED-related control, you can replace "led1_mode" with it in the "-c led1_mode=0" parameter of the second command in this answer to see if the LED turns off. If not, you might try different values (1,2,etc...).

Downsides of this solution

In my case, when unplugging-plugging the USB cable of my webcam, i need to turn off the LED again.

More info

https://manpages.ubuntu.com/manpages/bionic/man1/v4l2-ctl.1.html

1
  • I know this is a older post, but you could create a udev rule that does automaticly turn of the LED if you plugin the webcam in.
    – Marc
    Commented Jan 1 at 12:23
0

Is motion installed?

dpkg -l "motion"

If the response is empty, it is not installed the the rest of my answer is not interesting for you.

If it is installed, is it running?

### use this
systemctl status motion
### or this:
ps -ef | grep motion

The easy way to test if it is running, run the following command and the light may turn off:

systemctl stop motion

If you don't need motion, stop (as shown above) and disable it:

systemctl disable motion

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