[FEATURE REQ] Device support: Samsung Galaxy Book Flex2

[RubenKelevra]

Is your feature request related to a problem? Please describe.
My Samsung device got a brightness sensor – which is under Windows only, used to turn on/off the keyboard backlights (which can be adjusted in brightness or turned off completely).

Neither the brightness sensor nor the keyboard backlights (nor the secondary camera of the device) is showing up under Linux – which is kind of strange.

The 720p webcam above the display is working fine for clight, so this ticket isn't about that I'm unable to use clight - it works great! :)

I noticed that the 720p device show's up with 3 possible input devices, which is kind of weird to me:

$ v4l2-ctl --list-devices
720p HD Camera: 720p HD Camera (usb-0000:00:14.0-6):
        /dev/video0
        /dev/video1
        /dev/media0
$ v4l2-ctl --list-devices
720p HD Camera: 720p HD Camera (usb-0000:00:14.0-6):
        /dev/video0
        /dev/video1
        /dev/media0

$ v4l2-ctl -d /dev/video0 --list-ctrls

User Controls

                     brightness 0x00980900 (int)    : min=0 max=127 step=1 default=64 value=64
                       contrast 0x00980901 (int)    : min=0 max=100 step=1 default=50 value=50
                     saturation 0x00980902 (int)    : min=0 max=8 step=1 default=4 value=4
                            hue 0x00980903 (int)    : min=-180 max=180 step=1 default=0 value=0
        white_balance_automatic 0x0098090c (bool)   : default=1 value=1
                          gamma 0x00980910 (int)    : min=100 max=500 step=1 default=300 value=300
           power_line_frequency 0x00980918 (menu)   : min=0 max=2 default=2 value=2 (60 Hz)
      white_balance_temperature 0x0098091a (int)    : min=2800 max=6500 step=10 default=3400 value=3400 flags=inactive
                      sharpness 0x0098091b (int)    : min=0 max=8 step=1 default=4 value=4
         backlight_compensation 0x0098091c (int)    : min=0 max=1 step=1 default=0 value=0

Camera Controls

                  auto_exposure 0x009a0901 (menu)   : min=0 max=3 default=3 value=3 (Aperture Priority Mode)
         exposure_time_absolute 0x009a0902 (int)    : min=50 max=10000 step=1 default=166 value=166 flags=inactive
$ v4l2-ctl -d /dev/video1 --list-ctrls
$ v4l2-ctl -d /dev/media0 --list-ctrls
Unable to detect what device /dev/media0 is, exiting.

So just a wild uneducated guess: /dev/video1 is the secondary camera, which needs to be activated (or is just not supported) before using. And /dev/media0 is the brightness sensor?

I'm kind of stuck, so I thought I'm asking for advice here:

The devices I found (which could be related):

lspci

# lspci -v
[...]
00:12.0 Serial controller: Intel Corporation Tiger Lake-LP Integrated Sensor Hub (rev 20) (prog-if 00 [8250])
        DeviceName: Onboard - Other
        Subsystem: Samsung Electronics Co Ltd Device c194
        Flags: bus master, fast devsel, latency 0, IRQ 16, IOMMU group 8
        Memory at 603e170000 (64-bit, non-prefetchable) [size=64K]
        Capabilities: [80] Power Management version 3
        Capabilities: [90] Vendor Specific Information: Len=14 <?>
        Kernel driver in use: intel_ish_ipc
        Kernel modules: intel_ish_ipc
[...]
00:15.0 Serial bus controller: Intel Corporation Tiger Lake-LP Serial IO I2C Controller #0 (rev 20)
        DeviceName: Onboard - Other
        Subsystem: Samsung Electronics Co Ltd Device c194
        Flags: bus master, fast devsel, latency 0, IRQ 27, IOMMU group 11
        Memory at 4017000000 (64-bit, non-prefetchable) [virtual] [size=4K]
        Capabilities: [80] Power Management version 3
        Capabilities: [90] Vendor Specific Information: Len=14 <?>
        Kernel driver in use: intel-lpss
        Kernel modules: intel_lpss_pci

00:15.1 Serial bus controller: Intel Corporation Tiger Lake-LP Serial IO I2C Controller #1 (rev 20)
        DeviceName: Onboard - Other
        Subsystem: Samsung Electronics Co Ltd Device c194
        Flags: bus master, fast devsel, latency 0, IRQ 40, IOMMU group 11
        Memory at 4017001000 (64-bit, non-prefetchable) [virtual] [size=4K]
        Capabilities: [80] Power Management version 3
        Capabilities: [90] Vendor Specific Information: Len=14 <?>
        Kernel driver in use: intel-lpss
        Kernel modules: intel_lpss_pci

00:15.2 Serial bus controller: Intel Corporation Tiger Lake-LP Serial IO I2C Controller #2 (rev 20)
        DeviceName: Onboard - Other
        Subsystem: Samsung Electronics Co Ltd Device c194
        Flags: bus master, fast devsel, latency 0, IRQ 29, IOMMU group 11
        Memory at 4017002000 (64-bit, non-prefetchable) [virtual] [size=4K]
        Capabilities: [80] Power Management version 3
        Capabilities: [90] Vendor Specific Information: Len=14 <?>
        Kernel driver in use: intel-lpss
        Kernel modules: intel_lpss_pci

00:15.3 Serial bus controller: Intel Corporation Tiger Lake-LP Serial IO I2C Controller #3 (rev 20)
        DeviceName: Onboard - Other
        Subsystem: Samsung Electronics Co Ltd Device c194
        Flags: bus master, fast devsel, latency 0, IRQ 30, IOMMU group 11
        Memory at 4017003000 (64-bit, non-prefetchable) [virtual] [size=4K]
        Capabilities: [80] Power Management version 3
        Capabilities: [90] Vendor Specific Information: Len=14 <?>
        Kernel driver in use: intel-lpss
        Kernel modules: intel_lpss_pci
[...]

lsusb

# lsusb -v

[...]

Bus 003 Device 003: ID 2b7e:0134 Generic 720p HD Camera
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.01
  bDeviceClass          239 Miscellaneous Device
  bDeviceSubClass         2 
  bDeviceProtocol         1 Interface Association
  bMaxPacketSize0        64
  idVendor           0x2b7e 
  idProduct          0x0134 
  bcdDevice            0.07
  iManufacturer           3 Generic
  iProduct                1 720p HD Camera
  iSerial                 2 200901010001
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x02b3
    bNumInterfaces          2
    bConfigurationValue     1
    iConfiguration          4 USB Camera
    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               5 720p HD Camera
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      1 Video Control
      bInterfaceProtocol      0 
      iInterface              5 720p HD Camera
      VideoControl Interface Descriptor:
        bLength                13
        bDescriptorType        36
        bDescriptorSubtype      1 (HEADER)
        bcdUVC               1.00
        wTotalLength       0x006b
        dwClockFrequency       15.000000MHz
        bInCollection           1
        baInterfaceNr( 0)       1
      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           0x0020000a
          Auto-Exposure Mode
          Exposure Time (Absolute)
      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               6
        iTerminal               0 
      VideoControl Interface Descriptor:
        bLength                27
        bDescriptorType        36
        bDescriptorSubtype      6 (EXTENSION_UNIT)
        bUnitID                 4
        guidExtensionCode         {1229a78c-47b4-4094-b0ce-db07386fb938}
        bNumControls            2
        bNrInPins               1
        baSourceID( 0)          2
        bControlSize            2
        bmControls( 0)       0x00
        bmControls( 1)       0x06
        iExtension              0 
      VideoControl Interface Descriptor:
        bLength                29
        bDescriptorType        36
        bDescriptorSubtype      6 (EXTENSION_UNIT)
        bUnitID                 6
        guidExtensionCode         {26b8105a-0713-4870-979d-da79444bb68e}
        bNumControls            4
        bNrInPins               1
        baSourceID( 0)          4
        bControlSize            4
        bmControls( 0)       0x38
        bmControls( 1)       0x00
        bmControls( 2)       0x04
        bmControls( 3)       0x00
        iExtension              6 Realtek Extended Controls Unit
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0010  1x 16 bytes
        bInterval               6
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      VideoStreaming Interface Descriptor:
        bLength                            15
        bDescriptorType                    36
        bDescriptorSubtype                  1 (INPUT_HEADER)
        bNumFormats                         2
        wTotalLength                   0x01a9
        bEndpointAddress                 0x81  EP 1 IN
        bmInfo                              0
        bTerminalLink                       3
        bStillCaptureMethod                 1
        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                6
        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                            30
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         1
        bmCapabilities                   0x01
          Still image supported
        wWidth                           1280
        wHeight                           720
        dwMinBitRate                442368000
        dwMaxBitRate                442368000
        dwMaxVideoFrameBufferSize     1843200
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  1
        dwFrameInterval( 0)            333333
      VideoStreaming Interface Descriptor:
        bLength                            30
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         2
        bmCapabilities                   0x01
          Still image supported
        wWidth                            640
        wHeight                           480
        dwMinBitRate                147456000
        dwMaxBitRate                147456000
        dwMaxVideoFrameBufferSize      614400
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  1
        dwFrameInterval( 0)            333333
      VideoStreaming Interface Descriptor:
        bLength                            30
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         3
        bmCapabilities                   0x01
          Still image supported
        wWidth                            640
        wHeight                           360
        dwMinBitRate                110592000
        dwMaxBitRate                110592000
        dwMaxVideoFrameBufferSize      460800
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  1
        dwFrameInterval( 0)            333333
      VideoStreaming Interface Descriptor:
        bLength                            30
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         4
        bmCapabilities                   0x01
          Still image supported
        wWidth                            352
        wHeight                           288
        dwMinBitRate                 48660480
        dwMaxBitRate                 48660480
        dwMaxVideoFrameBufferSize      202752
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  1
        dwFrameInterval( 0)            333333
      VideoStreaming Interface Descriptor:
        bLength                            30
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         5
        bmCapabilities                   0x01
          Still image supported
        wWidth                            320
        wHeight                           240
        dwMinBitRate                 36864000
        dwMaxBitRate                 36864000
        dwMaxVideoFrameBufferSize      153600
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  1
        dwFrameInterval( 0)            333333
      VideoStreaming Interface Descriptor:
        bLength                            30
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         6
        bmCapabilities                   0x01
          Still image supported
        wWidth                            160
        wHeight                           120
        dwMinBitRate                  9216000
        dwMaxBitRate                  9216000
        dwMaxVideoFrameBufferSize       38400
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  1
        dwFrameInterval( 0)            333333
      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                6
        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                            30
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         1
        bmCapabilities                   0x01
          Still image supported
        wWidth                           1280
        wHeight                           720
        dwMinBitRate                147456000
        dwMaxBitRate                147456000
        dwMaxVideoFrameBufferSize     1843200
        dwDefaultFrameInterval        1000000
        bFrameIntervalType                  1
        dwFrameInterval( 0)           1000000
      VideoStreaming Interface Descriptor:
        bLength                            30
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         2
        bmCapabilities                   0x01
          Still image supported
        wWidth                            640
        wHeight                           480
        dwMinBitRate                147456000
        dwMaxBitRate                147456000
        dwMaxVideoFrameBufferSize      614400
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  1
        dwFrameInterval( 0)            333333
      VideoStreaming Interface Descriptor:
        bLength                            30
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         3
        bmCapabilities                   0x01
          Still image supported
        wWidth                            640
        wHeight                           360
        dwMinBitRate                110592000
        dwMaxBitRate                110592000
        dwMaxVideoFrameBufferSize      460800
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  1
        dwFrameInterval( 0)            333333
      VideoStreaming Interface Descriptor:
        bLength                            30
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         4
        bmCapabilities                   0x01
          Still image supported
        wWidth                            352
        wHeight                           288
        dwMinBitRate                 48660480
        dwMaxBitRate                 48660480
        dwMaxVideoFrameBufferSize      202752
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  1
        dwFrameInterval( 0)            333333
      VideoStreaming Interface Descriptor:
        bLength                            30
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         5
        bmCapabilities                   0x01
          Still image supported
        wWidth                            320
        wHeight                           240
        dwMinBitRate                 36864000
        dwMaxBitRate                 36864000
        dwMaxVideoFrameBufferSize      153600
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  1
        dwFrameInterval( 0)            333333
      VideoStreaming Interface Descriptor:
        bLength                            30
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         6
        bmCapabilities                   0x01
          Still image supported
        wWidth                            160
        wHeight                           120
        dwMinBitRate                  9216000
        dwMaxBitRate                  9216000
        dwMaxVideoFrameBufferSize       38400
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  1
        dwFrameInterval( 0)            333333
      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              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0080  1x 128 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              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 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              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 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              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0b00  2x 768 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       5
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 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       6
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x1380  3x 896 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       7
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x13fc  3x 1020 bytes
        bInterval               1
Binary Object Store Descriptor:
  bLength                 5
  bDescriptorType        15
  wTotalLength       0x0021
  bNumDeviceCaps          1
  Platform Device Capability:
    bLength                28
    bDescriptorType        16
    bDevCapabilityType      5
    bReserved               0
    PlatformCapabilityUUID    {d8dd60df-4589-4cc7-9cd2-659d9e648a9f}
    CapabilityData[0]    0x00
    CapabilityData[1]    0x00
    CapabilityData[2]    0x00
    CapabilityData[3]    0x0a
    CapabilityData[4]    0x7e
    CapabilityData[5]    0x01
    CapabilityData[6]    0x5f
    CapabilityData[7]    0x00
Device Status:     0x0000
  (Bus Powered)

Bus 003 Device 002: ID 04e8:730b Samsung Electronics Co., Ltd Fingerprint Sensor Device - 730B
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            0 
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0         8
  idVendor           0x04e8 Samsung Electronics Co., Ltd
  idProduct          0x730b 
  bcdDevice            0.00
  iManufacturer           1 Cypress
  iProduct                2 Fingerprint Sensor Device - 730B
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x0027
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower              500mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           3
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass      2 
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x01  EP 1 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval              10
Device Status:     0x0001
  Self Powered

[flying-x]

Did you check the output of ddcutil detect? It might be that the OLED screen doesn't have a backlight that you can control.

I use icc-brightness-gnome-git AUR package from arch to simulate brightness change in software.

[FedeDP]

Hi!
I think perhaps Linux does not support neither your brightness sensor nor your keyboard backlight :)
Not much we can do i'd say!

[spikespaz]

OLED brightness can be controlled by multiplying each pixel by a brightness factor. This can be done entirely in userspace, for example by GammaStep.

I found another project, wl-gammarelay-rs which should support this use-case, but I currently have an open issue because it doesn't work on my machine.

I think Clight should implement something similar, I would come back because now I also have a device with an ambient light sensor.

[FedeDP]

I think Clight should implement something similar, I would come back because now I also have a device with an ambient light sensor.

Latest Clightd tag supports so-called "software emulated backlight" management for all monitors that are not supported by ddc.
Care to try? I am not sure whether it will work (ie: i am not sure whether your display will try to use sysfs method instead. In that case, i might add a new env var to force-enable emulated backlight mode even for internal sysfs displays).
For more info: https://github.com/FedeDP/Clightd/wiki/Backlight

Also, in Clightd master i disabled by default the emulated backlight support since it was causing some troubles for me when i attached the laptop to my TV, but afaik it worked fine with internal laptop display or my normal external monitor while developing and testing the feature.

[spikespaz]

For me to use this feature, I would need to be sure it wouldn't try to adjust the (emulated) brightness of two other displays, but rather, only the internal one.

Your concern about it trying to use ACPI sysfs is most likely a problem, test -f /sys/class/backlight/amdgpu_bl0/brightness returns 0 so that fine does exist. Writing a value to the file has no visible effect.

Perhaps configure Clight to use emulated backlight for specific displays?

[FedeDP]

Perhaps configure Clight to use emulated backlight for specific displays?

Yep makes sense! Please can you open a feat req on Clightd? :)
Thanks!