How to programmatically scan hdmi devices on Linux? - linux

Our application is written in C++ and runs on Ubuntu. I need to scan all the connected HDMI devices and obtain information such as device model, serial number, etc. Can someone please point me in the right direction? Regards.

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Advice needed: low-level signal at 10m distance

audio noob here. Please be gentle.
I'm required to design a box with a jack for a headset and connector for an unknown cable going to a Windows desktop PC.
Headset has the standard 3.5mm plug for microphone, r speaker, l speaker, and ground.
Intention is there's a user at desktop PC who will communicate with user of the headset.
Questions:
1) the box is only pass-through. what's the best cable I can use to pass these low-level signals between headset and Windows desktop PC? distance is 10-15 meters.
2) at desktop PC side, what's the best hardware I can use so Windows desktop PC can receive/process these signals? I'm thinking USB link to PC but not sure what's available out there.
TIA!

Bluetooth Device Tracker/ Finder

I lost my Bluetooth earphones and had been searching for it recently. I would like to ask if there are any programs (or how I can code my own) that can help look for a paired but not connected Bluetooth device. Thanks in advance and much appreciated.
Any app can find your bluetooth earphones, only if it is ON. From my perspective, one suggestion is to [save the name or device address]remove pairing from your phone for the headset and do a bluetooth search . If your headset appears on the device discovery list, then it should be around.

Linux USB Disable USB Power Only

I've have been looking for a while and though a lot of Exchange Q&A's have helped, I haven't exactly received the answer I'm looking for.
Going off the question asked here: How can I detect a USB port being used for charging in Linux?
I felt as if it needed it's own question. I have a USB Powered Hub for charging smart phones and I wish to control the power (On/Off only) to each of the ports individually.
Using a USB charging cable, Linux cannot detect that a device is plugged in, so using a USB data cable might be more useful to this scenario.
Essentially, I want Linux to be able to detect when a device is plugged in, however I do not want any data transmission to occur between the device and Linux. Simply only power. By detecting the device being plugged in, I want to be able to control whether power will flow to the device or not, but no data transmission.
I'm currently testing with uhubctl, however when enabling/disabling the port, unfortunately it controls both power/data where I wish to cut off data entirely and only allow power to the device.
Is it possible to using a USB Data Cable detect a device plugged in, then essentially disable the phone talking to the computer entirely, but still allow power to flow to the device?
If not, the other option I was thinking is if there is a USB Power Hub out there that can tell Linux if a new device has been plugged in or not and I can tell it whether to charge or not?
Any input would be greatly appreciated.

Enumerate commands available for a usb chip in fedora 24

I am learning to program a USB device (iBall 3.5g USB Dongle) using libusb.h header library.
Until now I am able to identify my device using the Vendor ID and also open the device for operation.
As a next step I would like to know the available commands (or the controls) for example : command to scan the surroundings for available GSM networks.
Obviously I will have to talk to the devices' firmware to extract the necessary information.
I tried to search for the technical datasheet for the 3g dongle, but couldn't find any.
The dongle is powered by a Qualcomm chip
Do you know any of the methods in which I can get the control commands for a usb device ?
Thanks in advance.
There is no simple procedure for figuring out what commands a USB device has. You need to use a combination of looking at the descriptors reported by the device, seeing if the device supports any particular USB device class, reading the USB specification, and maybe doing some reverse engineering using a protocol analyzer.
A good first step would be for you to use lsusb -v to print human-readable descriptions of the device's USB descriptors.

Raspbian - Read data from HID device

I got a measuring instrument which can measure light intensity and this instrument can be connected to a PC via USB.
I now want to be able to read the values from the device via a Raspberry.
When the instrument is connected to the Pi, it shows up when entering 'lsusb' to the terminal and it is also listed under '/dev/usb' as hiddev1
But how can i actually grab the data from the device?
When i enter 'sudo cat /dev/usb/hiddev1' nothing happens.
Thanks in advance for your help
Try using HIDAPI, a cross-platform library for accessing Human Interface Devices.

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