编辑：原来是硬件问题。更换了我的无线网卡，现在一切似乎都运行正常。
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我最近从 Kubuntu 19.10 更新到了 Kubuntu 20.04（内核 5.4），现在我的 wifi 无法使用。它似乎偶尔能用，但实际上根本无法使用。
通过运行我注意到的第一件事dmesg |grep iwlwifi是它似乎正在尝试加载，iwlwifi-cc-a0-50.ucode然后是iwlwifi-cc-a0-49.ucode两个在我的系统上不存在的东西，最后它会加载iwlwifi-cc-a0-48.ucode。
然而，https://www.intel.com/content/www/us/en/support/articles/000005511/network-and-io/wireless-networking.html似乎表明我的设备的正确驱动程序是。因此，我从 git 树下载了它，并通过覆盖来iwlwifi-cc-a0-46.ucode强制我的内核加载它。iwlwifi-cc-a0-48.ucode/lib/firmware
我以为这样可以解决问题，但并没有，而且我现在还不知道该怎么办。这是 的当前输出dmesg |grep iwlwifi。任何帮助都将不胜感激。
jasonb@jason-pc:~$ dmesg |grep iwlwifi
[ 3.040001] iwlwifi 0000:02:00.0: enabling device (0000 -> 0002)
[ 3.063694] iwlwifi 0000:02:00.0: Found debug destination: EXTERNAL_DRAM
[ 3.063696] iwlwifi 0000:02:00.0: Found debug configuration: 0
[ 3.063885] iwlwifi 0000:02:00.0: loaded firmware version 46.177b3e46.0 op_mode iwlmvm
[ 3.112782] iwlwifi 0000:02:00.0: Detected Intel(R) Wi-Fi 6 AX200 160MHz, REV=0x340
[ 3.125898] iwlwifi 0000:02:00.0: Applying debug destination EXTERNAL_DRAM
[ 3.126315] iwlwifi 0000:02:00.0: Allocated 0x00400000 bytes for firmware monitor.
[ 3.283955] iwlwifi 0000:02:00.0: base HW address: 50:eb:71:da:33:6a
[ 3.301432] iwlwifi 0000:02:00.0 wlp2s0: renamed from wlan0
[ 4.360449] iwlwifi 0000:02:00.0: Applying debug destination EXTERNAL_DRAM
[ 4.518769] iwlwifi 0000:02:00.0: FW already configured (0) - re-configuring
[ 4.530986] iwlwifi 0000:02:00.0: BIOS contains WGDS but no WRDS
[ 12.240895] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 13.704339] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 14.728587] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 19.720571] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 20.776456] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 23.720531] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 24.776483] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 27.464338] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 28.744363] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 29.800544] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 39.024188] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 39.688581] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 40.776720] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 52.716839] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 53.800487] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 54.760647] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 65.612484] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 66.728634] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 67.688562] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 79.679563] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 80.680600] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 81.800606] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 91.590532] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 92.808675] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
[ 93.800381] iwlwifi 0000:02:00.0: No beacon heard and the time event is over already...
同样在关机时，这些消息会在黑屏上短暂闪烁：
[ 4.448530] iwlwifi 0000:02:00.0: BIOS contains WGDS but no WRDS
[ 4.536318] Bluetooth hci0: Failed to send Intel_Write_DDC (-22)
答案1
TL;DR-
sudo apt remove backport-iwlwifi-dkms
功劳应得者： Ubuntu 20.04 网络性能极慢
我遇到了（看似）相同的问题。我使用的是配备英特尔 AX200 wifi 卡的 Dell XPS 7390 开发者版；附带 Ubuntu 18.04，我升级到 20.04 并使用内核版本 5.4，然后我开始遇到这些相同的问题 - 我的 wifi 不断中断，因此看起来很慢，尽管速度测试表明并非如此。
我运行了上面的命令，但还是出现了同样的错误 - 我从英特尔网站（上面有链接）升级了我的固件，以防万一。我还尝试按照我链接中的一个答案的建议调整 TLP。我在尝试每件事之间都进行了重新启动，删除软件包对我来说是解决问题的办法。如果你有这个软件包，它可能是罪魁祸首。祝你好运。