我的笔记本电脑是 Thinkpas T400，内置英特尔 wifi link 5100 AGN。每次重启后，我的无线连接都会在一段时间后丢失。这种情况发生在我当前的 64 位 14.04 和之前的 32 位 12.04 中。（在 14.04 中，有时我的以太网适配器也无法工作。）
我通过谷歌搜索“intel wifi 5100 AGN Ubuntu”找到了一些讨论，他们尝试了不同的方法但并没有解决问题。
我在这里发布了我的无线适配器wlan0及其驱动程序的dmesg 输出iwlwifi，希望能有所帮助。
$ dmesg | grep wlan0
[ 22.680318] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[ 29.424514] wlan0: authenticate with 00:25:9c:1b:57:21
[ 29.427265] wlan0: send auth to 00:25:9c:1b:57:21 (try 1/3)
[ 29.429960] wlan0: authenticated
[ 29.430048] iwlwifi 0000:03:00.0 wlan0: disabling HT as WMM/QoS is not supported by the AP
[ 29.430051] iwlwifi 0000:03:00.0 wlan0: disabling VHT as WMM/QoS is not supported by the AP
[ 29.432078] wlan0: associate with 00:25:9c:1b:57:21 (try 1/3)
[ 29.434535] wlan0: RX AssocResp from 00:25:9c:1b:57:21 (capab=0x411 status=0 aid=5)
[ 29.437742] wlan0: associated
[ 29.437771] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[ 30.444281] wlan0: deauthenticating from 00:25:9c:1b:57:21 by local choice (Reason: 2=PREV_AUTH_NOT_VALID)
[ 30.446133] wlan0: authenticate with 00:25:9c:1b:57:21
[ 30.446981] wlan0: send auth to 00:25:9c:1b:57:21 (try 1/3)
[ 30.449875] wlan0: authenticated
[ 30.450038] iwlwifi 0000:03:00.0 wlan0: disabling HT as WMM/QoS is not supported by the AP
[ 30.450041] iwlwifi 0000:03:00.0 wlan0: disabling VHT as WMM/QoS is not supported by the AP
[ 30.452151] wlan0: associate with 00:25:9c:1b:57:21 (try 1/3)
[ 30.454658] wlan0: RX AssocResp from 00:25:9c:1b:57:21 (capab=0x411 status=0 aid=5)
[ 30.457904] wlan0: associated
[ 5120.374230] wlan0: deauthenticated from 00:25:9c:1b:57:21 (Reason: 7=CLASS3_FRAME_FROM_NONASSOC_STA)
[ 5123.676199] wlan0: authenticate with 00:25:9c:1b:57:21
[ 5123.677937] wlan0: send auth to 00:25:9c:1b:57:21 (try 1/3)
[ 5123.680496] wlan0: authenticated
[ 5123.680754] iwlwifi 0000:03:00.0 wlan0: disabling HT as WMM/QoS is not supported by the AP
[ 5123.680763] iwlwifi 0000:03:00.0 wlan0: disabling VHT as WMM/QoS is not supported by the AP
[ 5123.684315] wlan0: associate with 00:25:9c:1b:57:21 (try 1/3)
[ 5123.688858] wlan0: RX AssocResp from 00:25:9c:1b:57:21 (capab=0x411 status=0 aid=5)
[ 5123.691922] wlan0: associated
[16757.341736] wlan0: deauthenticated from 00:25:9c:1b:57:21 (Reason: 7=CLASS3_FRAME_FROM_NONASSOC_STA)
[16757.380215] wlan0: authenticate with 00:25:9c:1b:57:21
[16757.386911] wlan0: send auth to 00:25:9c:1b:57:21 (try 1/3)
[16757.391132] wlan0: authenticated
[16757.391424] iwlwifi 0000:03:00.0 wlan0: disabling HT as WMM/QoS is not supported by the AP
[16757.391433] iwlwifi 0000:03:00.0 wlan0: disabling VHT as WMM/QoS is not supported by the AP
[16757.392110] wlan0: associate with 00:25:9c:1b:57:21 (try 1/3)
[16757.395611] wlan0: RX AssocResp from 00:25:9c:1b:57:21 (capab=0x411 status=0 aid=2)
[16757.397671] wlan0: associated
[21321.548607] wlan0: deauthenticated from 00:25:9c:1b:57:21 (Reason: 7=CLASS3_FRAME_FROM_NONASSOC_STA)
$ dmesg | grep iwl
[ 13.916985] iwlwifi 0000:03:00.0: can't disable ASPM; OS doesn't have ASPM control
[ 13.917156] iwlwifi 0000:03:00.0: irq 50 for MSI/MSI-X
[ 13.959583] iwlwifi 0000:03:00.0: loaded firmware version 8.83.5.1 build 33692 op_mode iwldvm
[ 14.475382] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEBUG disabled
[ 14.475386] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEBUGFS enabled
[ 14.475387] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEVICE_TRACING enabled
[ 14.475389] iwlwifi 0000:03:00.0: Detected Intel(R) WiFi Link 5100 AGN, REV=0x54
[ 14.475454] iwlwifi 0000:03:00.0: L1 Disabled - LTR Disabled
[ 14.500372] ieee80211 phy0: Selected rate control algorithm 'iwl-agn-rs'
[ 22.554089] iwlwifi 0000:03:00.0: L1 Disabled - LTR Disabled
[ 22.554494] iwlwifi 0000:03:00.0: Radio type=0x1-0x2-0x0
[ 22.651233] iwlwifi 0000:03:00.0: L1 Disabled - LTR Disabled
[ 22.651625] iwlwifi 0000:03:00.0: Radio type=0x1-0x2-0x0
[ 29.430048] iwlwifi 0000:03:00.0 wlan0: disabling HT as WMM/QoS is not supported by the AP
[ 29.430051] iwlwifi 0000:03:00.0 wlan0: disabling VHT as WMM/QoS is not supported by the AP
[ 30.450038] iwlwifi 0000:03:00.0 wlan0: disabling HT as WMM/QoS is not supported by the AP
[ 30.450041] iwlwifi 0000:03:00.0 wlan0: disabling VHT as WMM/QoS is not supported by the AP
[ 5123.680754] iwlwifi 0000:03:00.0 wlan0: disabling HT as WMM/QoS is not supported by the AP
[ 5123.680763] iwlwifi 0000:03:00.0 wlan0: disabling VHT as WMM/QoS is not supported by the AP
[16757.391424] iwlwifi 0000:03:00.0 wlan0: disabling HT as WMM/QoS is not supported by the AP
[16757.391433] iwlwifi 0000:03:00.0 wlan0: disabling VHT as WMM/QoS is not supported by the AP
$ ifconfig
eth0 Link encap:Ethernet HWaddr 00:24:7e:e0:62:50
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
Interrupt:20 Memory:fc600000-fc620000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:37304 errors:0 dropped:0 overruns:0 frame:0
TX packets:37304 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:3623278 (3.6 MB) TX bytes:3623278 (3.6 MB)
wlan0 Link encap:Ethernet HWaddr 00:26:c6:3e:30:34
inet addr:192.168.1.100 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::226:c6ff:fe3e:3034/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:102840 errors:0 dropped:0 overruns:0 frame:0
TX packets:96036 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:78001233 (78.0 MB) TX bytes:16544959 (16.5 MB)
$ lshw -C network
WARNING: you should run this program as super-user.
*-network
description: Ethernet interface
product: 82567LM Gigabit Network Connection
vendor: Intel Corporation
physical id: 19
bus info: pci@0000:00:19.0
logical name: eth0
version: 03
serial: 00:24:7e:e0:62:50
capacity: 1Gbit/s
width: 32 bits
clock: 33MHz
capabilities: bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=2.3.2-k firmware=1.8-3 latency=0 link=no multicast=yes port=twisted pair
resources: irq:45 memory:fc600000-fc61ffff memory:fc625000-fc625fff ioport:1840(size=32)
*-network
description: Wireless interface
product: PRO/Wireless 5100 AGN [Shiloh] Network Connection
vendor: Intel Corporation
physical id: 0
bus info: pci@0000:03:00.0
logical name: wlan0
version: 00
serial: 00:26:c6:3e:30:34
width: 64 bits
clock: 33MHz
capabilities: bus_master cap_list ethernet physical wireless
configuration: broadcast=yes driver=iwlwifi driverversion=3.16.0-31-generic firmware=8.83.5.1 build 33692 ip=192.168.1.100 latency=0 link=yes multicast=yes wireless=IEEE 802.11abgn
resources: irq:50 memory:f4200000-f4201fff