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krzyzak

Member

Registered: 2019-06-07

Posts: 1

Disabling fingerprint reader on XPS 9380

Hello,

I have an Dell XPS 13 9380 laptop with a fingerprint reader. I am/was aware that there are no drivers for this reader, and it won't work on Linux: not a big deal for me.
The problem that I recently discovered during the optimisations of battery usage is that it consistently draws from 1.5W up to 3W of power, being the most power-consuming piece of hardware in my laptop (okay, display backlight might be the most with max brightness, but that's just a sidenote )

I'd really like to disable it, so:

[xps krzyzak]# lsusb
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 004: ID 1050:0407 Yubico.com Yubikey 4 OTP+U2F+CCID
Bus 001 Device 003: ID 0489:e0a2 Foxconn / Hon Hai 
Bus 001 Device 002: ID 0c45:6723 Microdia 
Bus 001 Device 005: ID 27c6:5385  
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Looks like

Bus 001 Device 005: ID 27c6:5385

is the one I'm looking for:

lsusb -v

Bus 001 Device 005: ID 27c6:5385  
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass          239 Miscellaneous Device
  bDeviceSubClass         2 
  bDeviceProtocol         1 Interface Association
  bMaxPacketSize0        64
  idVendor           0x27c6 
  idProduct          0x5385 
  bcdDevice            1.00
  iManufacturer           1 HTMicroelectronics
  iProduct                2 Goodix Fingerprint Device 
  iSerial                 3 HTK32
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x004b
    bNumInterfaces          2
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower              100mA
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         0
      bInterfaceCount         2
      bFunctionClass          2 Communications
      bFunctionSubClass     255 
      bFunctionProtocol       1 
      iFunction               2 Goodix Fingerprint Device 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         2 Communications
      bInterfaceSubClass      2 Abstract (modem)
      bInterfaceProtocol      1 AT-commands (v.25ter)
      iInterface              0 
      CDC Header:
        bcdCDC               1.10
      CDC Call Management:
        bmCapabilities       0x00
        bDataInterface          1
      UNRECOGNIZED CDC:  04 24 ff 02
      CDC Union:
        bMasterInterface        0
        bSlaveInterface         1 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval             255
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass        10 CDC Data
      bInterfaceSubClass      0 
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x03  EP 3 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     0x81  EP 1 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               0
can't get device qualifier: Resource temporarily unavailable
can't get debug descriptor: Resource temporarily unavailable
Device Status:     0x0000
  (Bus Powered)

I've tried with:

echo "1-5" | tee /sys/bus/usb/drivers/usb/unbind
echo "suspend" > tee /sys/bus/usb/devices/1-5/power/level

but without any luck: fingerprint reader is still present in the powertop list.
I was also trying to find a way to disable it on BIOS level, but apparently, there's no option to do that there.
Is there any other option how could I disable it?

PS: I was initially strugling where should I put this post: whether to Kernel&Hardware or Laptop issues, decided to go here - if that's a wrong section, I'm really sorry about that

mcmeeking

Member

Registered: 2020-07-03

Posts: 1

Re: Disabling fingerprint reader on XPS 9380

Sorry to bump after so long but I found a solution for this so just posting here for posterity as this was the first post I found when looking for a solution to this problem.

Create /etc/udev/rules.d/disable-usb-device.rules:

ACTION=="add", ATTR{idVendor}=="27c6", ATTR{idProduct}=="5385", RUN="/bin/sh -c 'echo 0 > /sys/\$devpath/authorized'"

Originally taken from https://unix.stackexchange.com/question … nvironment