mjhjmtu

I've installed a minimal installation of CentOS 7, meaning no GUI, on my Dell XPS 15 9560 laptop. 
uname -r returns 3.10.0-862.11.6.el7.x86_64. 
The laptop does not have an Ethernet card, but it does have a Wi-Fi card. 
During the installation I configured a Wi-Fi connection and I could confirm that I received an IP address.

When booting into the OS, however, I don't have an active connection. I've tried to find out how to activate the Wi-Fi and establish a connection with the tools already installed (as I can't install any new ones), but to no avail.

I'm not sure exactly what is of interest but this is what I know:

• 
  ip addr shows that the interface (is that the correct term?) wls2s0 is DOWN.


• running nmtui (after systemctl enable NetworkManager and service NetworkManager start) shows the connection I created and it seems correct. After all I successfully connected during the installation. The "activate a connection" menu is empty, though.


• 
  nmcli d shows a row like so: wlp2s0 wifi unmanaged --
  


• 
  nmcli connection show lists my connection but the "device"-field is empty (--).


• 
  nmcli connection up <connection name> gives me the following error: Error: Connection activation failed: No suitable device found for this connection.

I suspect my Wi-Fi card is not active, but I'm not sure how to activate it. I've tried the Fn+PrtScr combination,
which usually activates it, but no luck.

Running lshw gave me some additional info. The Wi-Fi card is listed under pci devices as:

 *-network DISABLED
 description: Wireless interface
 product: QCA6174 802.11ac Wireless Network Adapter
 vendor: Qualcomm Atheros
 ...
 logical name: wlp2s0
 ...
 configuration: broadcast=yes driver=ath10k_pci driverversion=3.10.0-862.11.6.el7.x86_64 firmware=WLAN.RM.4.4.1-00051-QCARMSWP-1 latency=0 link=no multicast=yes wireless=IEEE 802.11 resources: irq:140 memory:ed200000-ed3fffff

so the driver seems to be ath10k_pci. 
Running lsmod | grep "ath10k" gives me the following:

ath10k_pci 47418 0
ath10k_core 325711 1 ath10k_pci
ath 29446 1 ath10k_core
mac80211 714741 1 ath10k_core
cfg80211 623433 3 ath,mac88211,ath10k_core

I'm not sure if the above means that the ath10k_pci driver is being loaded, though.

Neither lsusb nor lspci is present on the system.

Any suggestions, where do I go from here?

See https://bugs.launchpad.net/ubuntu/+source/linux-firmware/+bug/1520343 for instructions on the Ubuntu approach to fixing the issue. Here are what I think are the relevant extracts, but note that I have not tested this as I don't have your hardware:

If you have kernel 4.5.0

sudo mkdir -p /lib/firmware/ath10k/QCA6174/hw3.0/
sudo rm /lib/firmware/ath10k/QCA6174/hw3.0/* 2> /dev/null
sudo wget -O /lib/firmware/ath10k/QCA6174/hw3.0/board.bin https://github.com/kvalo/ath10k-firmware/blob/master/QCA6174/hw3.0/board.bin?raw=true
sudo wget -O /lib/firmware/ath10k/QCA6174/hw3.0/board-2.bin https://github.com/kvalo/ath10k-firmware/blob/master/QCA6174/hw3.0/board-2.bin?raw=true
sudo wget -O /lib/firmware/ath10k/QCA6174/hw3.0/firmware-4.bin https://github.com/kvalo/ath10k-firmware/blob/master/QCA6174/hw3.0/firmware-4.bin_WLAN.RM.2.0-00180-QCARMSWPZ-1?raw=true

Reboot or reload the ath10k_pci module and you should be able to connect.

Otherwise

sudo mkdir -p /lib/firmware/ath10k/QCA6174/hw3.0/
sudo rm /lib/firmware/ath10k/QCA6174/hw3.0/* 2> /dev/null
sudo wget -O /lib/firmware/ath10k/QCA6174/hw3.0/board.bin https://github.com/FireWalkerX/ath10k-firmware/blob/7e56cbb94182a2fdab110cf5bfeded8fd1d44d30/QCA6174/hw3.0/board-2.bin?raw=true
sudo wget -O /lib/firmware/ath10k/QCA6174/hw3.0/firmware-4.bin https://github.com/FireWalkerX/ath10k-firmware/blob/7e56cbb94182a2fdab110cf5bfeded8fd1d44d30/QCA6174/hw3.0/firmware-4.bin_WLAN.RM.2.0-00180-QCARMSWPZ-1?raw=true
sudo chmod +x /lib/firmware/ath10k/QCA6174/hw3.0/*

Reboot or reload the ath10k_pci module and you should be able to connect.

Caveats

A number of comments on the original link say that these fixes do not work straight off, and tweaks are supplied. I would strongly recommend you work your way through the entire thread. Read it twice - once to see what's going on, and the once (at least) to work out what needs applying in your situation. This isn't going to be easy.