好的，我已经用了几天了。最初，当我安装 ubuntu 14.04 lts 时，wifi 根本无法使用。但经过一些修复后，我让它工作了，尽管它仍然不太稳定并且很慢。我按以下顺序尝试过：
- 根据本页给出的第一个答案安装新的驱动程序不稳定的 WiFi 连接 Ubuntu 14.04 - Lenovo G40-70 rtl8723be
- 根据本页给出的第一个答案安装另一个驱动程序Ubuntu 14.04 中 rtl8723be 的 Wifi 问题
- 然后将我的内核升级到 3.16.0-031600-generic。
echo "options rtl8723be fwlps=0" | sudo tee /etc/modprobe.d/rtl8723be.conf根据以下信息申请https://wiki.archlinux.org/index.php/Wireless_network_configuration#rtl8723ae.2Frtl8723be
这并不是说 wifi 完全不能用，而是它的速度实在太慢了，让人很郁闷。lspci 的输出：
00:00.0 Host bridge: Intel Corporation Broadwell-U Host Bridge -OPI (rev 09)
00:02.0 VGA compatible controller: Intel Corporation Broadwell-U Integrated Graphics (rev 09)
00:03.0 Audio device: Intel Corporation Broadwell-U Audio Controller (rev 09)
00:04.0 Signal processing controller: Intel Corporation Broadwell-U Camarillo Device (rev 09)
00:14.0 USB controller: Intel Corporation Wildcat Point-LP USB xHCI Controller (rev 03)
00:16.0 Communication controller: Intel Corporation Wildcat Point-LP MEI Controller #1 (rev 03)
00:1b.0 Audio device: Intel Corporation Wildcat Point-LP High Definition Audio Controller (rev 03)
00:1c.0 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root Port #1 (rev e3)
00:1c.2 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root Port #3 (rev e3)
00:1c.5 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root Port #6 (rev e3)
00:1d.0 USB controller: Intel Corporation Wildcat Point-LP USB EHCI Controller (rev 03)
00:1f.0 ISA bridge: Intel Corporation Wildcat Point-LP LPC Controller (rev 03)
00:1f.2 SATA controller: Intel Corporation Wildcat Point-LP SATA Controller [AHCI Mode] (rev 03)
00:1f.3 SMBus: Intel Corporation Wildcat Point-LP SMBus Controller (rev 03)
00:1f.6 Signal processing controller: Intel Corporation Wildcat Point-LP Thermal Management Controller (rev 03)
07:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E PCI Express Fast Ethernet controller (rev 07)
0d:00.0 Network controller: Realtek Semiconductor Co., Ltd. RTL8723BE PCIe Wireless Network Adapter
输出iw dev wlan0 station dump：
Station c4:e9:84:87:e1:86 (on wlan0)
inactive time: 48 ms
rx bytes: 3331226
rx packets: 15891
tx bytes: 1163486
tx packets: 4703
tx retries: 0
tx failed: 0
signal: -74 dBm
signal avg: -73 dBm
tx bitrate: 150.0 MBit/s MCS 7 40Mhz short GI
authorized: yes
authenticated: yes
preamble: long
WMM/WME: yes
MFP: no
TDLS peer: no
任何帮助将非常感激。
编辑于2015年12月5日：
我刚刚升级到 16.04。除了 wifi 之外，一切都运行良好。问题依然存在。Wifi 保持连接状态，但运行速度非常慢。可能比以前慢。因此输出为：
00:00.0 Host bridge: Intel Corporation Broadwell-U Host Bridge -OPI (rev 09)
00:02.0 VGA compatible controller: Intel Corporation Broadwell-U Integrated Graphics (rev 09)
00:03.0 Audio device: Intel Corporation Broadwell-U Audio Controller (rev 09)
00:04.0 Signal processing controller: Intel Corporation Broadwell-U Camarillo Device (rev 09)
00:14.0 USB controller: Intel Corporation Wildcat Point-LP USB xHCI Controller (rev 03)
00:16.0 Communication controller: Intel Corporation Wildcat Point-LP MEI Controller #1 (rev 03)
00:1b.0 Audio device: Intel Corporation Wildcat Point-LP High Definition Audio Controller (rev 03)
00:1c.0 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root Port #1 (rev e3)
00:1c.2 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root Port #3 (rev e3)
00:1c.5 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root Port #6 (rev e3)
00:1d.0 USB controller: Intel Corporation Wildcat Point-LP USB EHCI Controller (rev 03)
00:1f.0 ISA bridge: Intel Corporation Wildcat Point-LP LPC Controller (rev 03)
00:1f.2 SATA controller: Intel Corporation Wildcat Point-LP SATA Controller [AHCI Mode] (rev 03)
00:1f.3 SMBus: Intel Corporation Wildcat Point-LP SMBus Controller (rev 03)
00:1f.6 Signal processing controller: Intel Corporation Wildcat Point-LP Thermal Management Controller (rev 03)
07:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8101/2/6E PCI Express Fast/Gigabit Ethernet controller (rev 07)
0d:00.0 Network controller: Realtek Semiconductor Co., Ltd. RTL8723BE PCIe Wireless Network Adapter
并且iw dev wlan0 station dump是：
Station c4:e9:84:87:e1:86 (on wlan0)
inactive time: 2404 ms
rx bytes: 1351602
rx packets: 8268
tx bytes: 524504
tx packets: 1874
tx retries: 0
tx failed: 0
signal: -66 dBm
signal avg: -66 dBm
tx bitrate: 150.0 MBit/s MCS 7 40MHz short GI
rx bitrate: 1.0 MBit/s
authorized: yes
authenticated: yes
preamble: long
WMM/WME: yes
MFP: no
TDLS peer: no