Multiple device support for Logitech Litra Glow.

[kootstra]

On my Windows 10 system I have 2 Logitech Litra Glow devices that are connected through a dock to my notebook. When I use the below scripts I am able to switch 1 on and off.

On
hidapitester.exe --quiet --vidpid 046D/C900 --usagePage FF43 --open --length 20 --send-output 0x11,0xff,0x04,0x1c,0x01

Off
hidapitester.exe --quiet --vidpid 046D/C900 --usagePage FF43 --open --length 20 --send-output 0x11,0xff,0x04,0x1c,0x00

Now, I am able to get both of them to switch on and off by moving to Microsoft Edge or Microsoft Word - not outlook, teams etc. Run the command. First one switches on. Move to browser to switch the second one on, and then run command to switch the first one off and then move to browser to switch the second one off.

The applications that do this have application specific settings in Logi Options+, but not for my Logitech Litra's but my mouse (MX Master 3).

Help to understand and improve is appreciated.

[todbot]

To distinguish between identical devices, you will need to write your own HID code that queries them for some aspect that is unique to each of them.

If the devices provide a USB standard serial number (which you would see with hidapitester --list-detail), then we could add an extra argument to select by serial number.

[fbn3799]

I would also like to have the option to control two or more devices. For now, what works for me is calling the function a couple of times in a row. The script seems to get one of the lights at random and if I call it more than once, both of the lights will respond most of the time. In rare cases, it only controls only one device. That's what I did:

function _hid() { /usr/local/bin/hidapitester --vidpid 046D/C901 --open --length 20 --send-output $1; /usr/local/bin/hidapitester --vidpid 046D/C901 --open --length 20 --send-output $1; /usr/local/bin/hidapitester --vidpid 046D/C901 --open --length 20 --send-output $1 }

I guess it's not stupid if it works :)

[mcuee]

Maybe the following option can be used.

--open-path <pathstr>       Open device by path (as in --list-detail)

mcuee@freebsd14:~/build/hidapitester $ sudo ./hidapitester --list-detail
04D8/003F: Microchip Technology Inc. - Simple HID Device Demo
  vendorId:      0x04D8
  productId:     0x003F
  usagePage:     0x0000
  usage:         0x0000
  serial_number: (null)
  interface:     0
  path: 0-4:1.0

mcuee@freebsd14:~/build/hidapitester $ sudo ./hidapitester --vidpid 04d8/003f --open --get-report-descriptor
Opening device, vid/pid: 0x04D8/0x003F
Report Descriptor:
 06 00 FF 09 01 A1 01 19 01 29 40 15 01 25 40 75 08 95 40 81 00 19 01 29 40 91 00 C0
Closing device

mcuee@freebsd14:~/build/hidapitester $ sudo ./hidapitester --open-path 0-4:1.0 --get-report-descriptor
Opening device. path: 0-4:1.0
Report Descriptor:
 06 00 FF 09 01 A1 01 19 01 29 40 15 01 25 40 75 08 95 40 81 00 19 01 29 40 91 00 C0
Closing device

[fbn3799]

Thank you very much, it worked for me!

[mcuee]

@kootstra
Please try the mentioned mentioned as well. Thanks.

--open-path <pathstr>       Open device by path (as in --list-detail)

[fbn3799]

Correction: It worked for me at first but not after reboot. The path string is updated after system reboot.

[mcuee]

That is normal. The path may change across reboot.

You have to get the path first before using the path.

[fbn3799]

Got it. Logically I understand that I need to first filter for my devices, from that list save all unique path strings and then open by path for each. Thing is, I'm not really a programmer and I don't know how to do that.

[fbn3799]

I figured it out with the help of ChatGPT. I needed to modify my _hid function like this:

function _hid() {
  # Get unique device paths
  device_paths=($( /usr/local/bin/hidapitester --vidpid 046D/B901 --list-detail | awk '/path:/ {print $2}' | sort -u ))

  # Iterate over each unique device path and execute all commands while it's open
  for path in "${device_paths[@]}"; do
    /usr/local/bin/hidapitester --open-path "$path" --length 20 --send-output $1 --send-output $2 --send-output $3
  done
}

But for it to work I also needed to update my function that I call for controlling on/off brightness and temperature all at once, because it did not work if they were in seperate functions calling the _hid. It would only open both devices the first time, not the second and third time. But I think this is better anyway since the devices only need to be opened once. My function looks like this now:

function light_brightest_sunlight() {
  _hid "0x11 0xff 0x04 0x1c 0x01" "0x11 0xff 0x04 0x4c 0x00 251" "0x11 0xff 0x04 0x9c 21 124"
}