I have a Lenovo X220 with Intel Centrino 6205 wireless adapter and Ubuntu 14.04 LTS installed as the sole operating system. I have a rather unique issue that I can't quite pin down. I have an HTC One M8 that I use a WiFi Hotspot using the integrated AOSP program in the settings. When I use it as a WiFi hotspot, my laptop won't connect to it, and when it does, it's very intermittent. I've googled around for a few hours to no avail. I've tried disabling the N mode, didn't work. Tried installing new microcode, but I got some error when using modprobe to load the new microcode (instructions were pretty vague). What makes this issue strange is no other computers have issues using my phone as a WiFi access point, and this even happened while other computers were connected to it browsing the web just fine. That leads me to believe it's the laptop. However, the laptop has no issue connecting to WiFi at home or at Starbucks, which leads me to believe it's my phone. Even more puzzling, it wouldn't connect even through a wired USB connection, something I've historically had no issues with.
As a workaround, the laptop has no issue tethering to my phone via bluetooth, so I've been using that instead, and it works rather well since it's lower power drain on both devices. However, I'd like to figure this out for when I do need higher performance. Actually, now that I think about it, the WiFi/USB tethering issues haven't started until I started using Bluetooth tethering. In any event, the issue seems persistent - reboots don't help.
Any suggestions to troubleshooting? I've seem to hit a wall.
If I understood that command correctly, it gets reinstalls kernel headers, grabs and compiles realtek drivers, then loads them into a configuration file? I'm not quite sure how that helps me. Maybe I'll follow the instructions on copying over the drivers with the Intel ones I have downloaded.
On a related note, is it better to use the newest version which came from a backport, or use the last version specifically designed for my kernel version? I'm guessing the latter but would like some confirmation.
My initial response was only for a problem that was similar to yours. I offered it simply as a potential source of information, on the basis of every little helps. Wish I could say for certain it would definitely be the solution for you too. Sorry, if you are disappointed.
Back up any config file you intend to change, so you can roll back if necessary. (I expect you already knew that, but it doesn't hurt to point it out, if you're a noob.)
I agree with your conclusion, that the drivers designed for the kernel you're using, would be the ones to use.
I just got an update on the issue. At least part of it is my phone. I recently installed Windows 8 on my X220 and also was having issues connecting to my WiFi hotspot. And then the WiFi connection was also intermittent on a work laptop (Sandy Bridge era HP Elitebook). Once I disabled bluetooth tethering on my phone the WiFi connection seems to be solid on the work computer, and Windows on my X220. I haven't thoroughly tested it on Ubuntu, but it took longer than usual to connect, and I had to reboot before it got the chance too because I'm still at work and needed Windows for a project. Hopefully this solves my issue, but I know the drivers for that particular wifi chipset on Linux documented to be buggy, so who knows.