Version：Ubuntu 16.10
Computer：Acer ASPIRE 4750G
Wireless adapter: Qualcomm Atheros AR9287 Wireless Network Adapter (PCI-Express) (rev01)
问题描述：重启或者重新安装系统后，检测不到Wi-Fi。具体表现为右上角Wi-Fi网络连接的图标是空的，没有半圈半圈的线。点击能够启动联网和启动Wi-Fi，但是就是检测不到任何的Wi-Fi。
问题分析：在终端输入 sudo lshw -C network ，提示无线网络不可用，得到的结果类似于：
*-network DISABLED
description: Wireless interface
product: AR9287 Wireless Network Adapter (PCI-Express)
vendor: Atheros Communications INc.
physical id: 0
bus info: pci@0000:06:00.0
logical name: wlan0
version: 01
serial: the-number
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress bus_master cap_list enternet physical wireless
configureation: broadcast=yes driver=ath9k driverversion=2.6.38-8-generic firmware=N/A latency=0 link=no multicast=yes wireless=IEEE 802.11bgn
resources: irq: 17 memory:d0200000-d020ffff
解决方法：
Try blacklisting the acer-wmi kernel module.
sudo gedit /etc/modprobe.d/blacklist.conf
add blacklist acer_wmi as a new line at the bottom of this file.
Then reboot.
原理：
edit:
The acer-wmi kernel module enables you to control the following:
the wireless LAN card radio
inbuilt Bluetooth adapter
inbuilt 3G card
mail LED of your laptop
brightness of the LCD panel
With regards to wireless, all acer-wmi does is enable the radio on the card. It is not responsible for the wireless LED - once the radio is enabled, this is down to the wireless driver for your card.
However for some acer laptop models - there is a conflict between the Acer firmware and the kernel implementation. This is why you need to blacklist.
一些网络调试的命令和方法：
uname -a
lspci
sudo lspci -vvnn
sudo lshw -C network
iwconfig //查看网络配置文件
dig www.baidu.com
sudo iwlist scanning //扫描电脑周边所有可看到的无线网络
ls -l /etc/NetworkManager/system-connections //查看已有的无线网络的配置文件