adb devices doesn't show phone linux Fedora

Question

First of all, I have a LG G2, and I'm using Fedora.
When I issue an adb devices command, I see no devices.

Steps I have taken to correct this:

• I have added the following to my 51-android.rules file. The first line is for another device.

SUBSYSTEMS=="usb", ATTRS{idVendor}=="22b8", ATTRS{idProduct}=="4366", MODE="0666" SUBSYSTEMS=="usb", ATTRS{idVendor}=="1004", ATTRS{idProduct}=="621c",MODE="0666"

• I have added 0x1004 to my adb_usb.ini file.
• I have restarted adb (by issuing "adb kill-server" and "adb start-server")
• I have enabled debugging on my phone (by turning on Developer Options and checking USB Debugging under settings)
• lsusb command returns the following

Bus 002 Device 008: ID 1004:621c LG Electronics, Inc.

Answer 1

In the end, what I did to resolve this is:

1. I had my USB cable plugged into the wrong port. I have 6 different ports, so I guess that first one I tried was messed up.
2. I had to change my USB Connection Method to "Internet Connection->Ethernet"
3. I had to enable installation from unknown sources. I went to Settings->Security->Checked "Unknown Source"
4. I had to Check "USB Debugging" BEFORE I hooked the USB cable up to my phone
5. I had to use the original cable shipped with my phone