I use DLINK DWA-125 on my PC as my network card doesn't support wireless connections and have an issue with my adapter using Ubuntu 15.10. I can see a lot of WiFi spots but the connection quality is 0 for each of those spots, even for my own spot which is 2-3 meters away from my PC (I can connect to it, yet it takes a lot of time and then I get ridiculously low connection speed - average ping on google.com is 2700ms).
I tried to make my notebook function as a WiFi hotspot and then connected to it from my PC to check the connection - it worked, but I could get the connection quality 3/4 and the speed of 2 MB/s only when I put my laptop very close to the adapter.
I've searched through a bunch of topics on different forums but most of them discuss making visibility of the adapter in Ubuntu, so I could get literally nothing out of that.
I use clear Ubuntu 15.10 x86 (installed yesterday) and the driver for the adapter was successfully configured during the install.
I put some info I got from terminal which may be useful:
driver: r8188eu
$ lsusb
Bus 002 Device 002: ID 2001:330f D-Link Corp.
$ iwconfig
wlx6c198f894581 IEEE 802.11bgn ESSID:"TP-LINK_B17466" Nickname:"<WIFI@REALTEK>"
Mode:Managed Frequency:2.442 GHz Access Point: C0:4A:00:B1:74:66
Bit Rate:150 Mb/s Sensitivity:0/0
Retry:off RTS thr:off Fragment thr:off
Power Management:off
Link Quality=75/100 Signal level=-48 dBm Noise level=0 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
lo no wireless extensions.
enp2s0 no wireless extensions.