飞行的蜗牛

一个正在觉醒的无名氏修行者，略懂编程，略懂音乐。

Ubuntu WIFI hardware-disable 解决办法

::: motto 和菜头
大多数时候，人不能被举起来摔在地上，人都是被自己的重量所绊倒的。
:::

最近由于工作需要，拿出妻子在 2011 年买的那款古老的 GateWay(acer) 笔记本来使用。这台 10 年前的笔记本今天来用确实是比较卡，但是把机械硬盘换成 SSD, 加了一根内存之后发现速度也还勉强能用。

拿到机器第一件事情就是把 Window7 格式化，装了 Ubuntu20.04，系统装完之后发现无线网卡没法启用，报错是 wifi hardware disabled。

排查尝试

遇到这个问题，我首先瞪大眼睛巡视了电脑一圈，没有发现有小的硬件开关，然后又在键盘的 FN 键上找了一圈，没有发现类似关闭 WIFI 的键，最后又不甘心的每个 FN 组合件都试了一下，发现依然无效。

直觉高速我，应该不是网卡硬件故障，否则应该无法识别硬件，而我使用 ifconfig -a 命令查询的时候明显能够列出那张无线网卡。

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ifconfig -a 
wlp3s0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        ether 20:6a:8a:54:a4:5e  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 19

但是此时有点病急乱投医了，想进一步确定到底是硬件原因还是软件原因，于是去京东商城买了一张支持 Linux 的 USB 无线网卡，我首先在我的台式机上编译了驱动装上之后，WIFI 能够正常工作。
然后再到笔记本上装一下，发现 USB WIFI 也提示 wifi hardware disabled。此时我已经能基本肯定是系统而并非硬件问题了。

应该是系统内核禁用了 WIFI 的功能，使用 rfkill 检查一下：

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0: acer-wireless: Wireless LAN
	Soft blocked: no
	Hard blocked: no
1: acer-bluetooth: Bluetooth
	Soft blocked: yes
	Hard blocked: no
2: phy0: Wireless LAN
	Soft blocked: no
	Hard blocked: yes

显然当前 Wireless 设备是被 Hard blocked 了。

解决方案

网上一顿搜索，看到有网友提醒说可能是硬件冲突了。回想一下我运行 rfkill list 的时候显示了两个无线模块: acer-wireless 和 phy0，所以猜测这两个模块可能有冲突。

lsmod | grep acer 发现系统启动了 acer_wmi 模块:

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root@YSS:~# lsmod | grep acer
acer_wmi               24576  0
sparse_keymap          16384  1 acer_wmi
wmi                    32768  2 acer_wmi,wmi_bmof
video                  53248  2 acer_wmi,i915

于是果断禁用 acer_wmi 模块：

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vim /etc/modprobe.d/blacklist.conf
# 在文件末尾增加 `blacklist acer_wmi`，保存并退出。

其实发现系统默认还禁用了很多过时或者弃用的模块，blacklist.conf 完整配置如下：

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# This file lists those modules which we don't want to be loaded by
# alias expansion, usually so some other driver will be loaded for the
# device instead.

# evbug is a debug tool that should be loaded explicitly
blacklist evbug

# these drivers are very simple, the HID drivers are usually preferred
blacklist usbmouse
blacklist usbkbd

# replaced by e100
blacklist eepro100

# replaced by tulip
blacklist de4x5

# causes no end of confusion by creating unexpected network interfaces
blacklist eth1394

# snd_intel8x0m can interfere with snd_intel8x0, doesn't seem to support much
# hardware on its own (Ubuntu bug #2011, #6810)
blacklist snd_intel8x0m

# Conflicts with dvb driver (which is better for handling this device)
blacklist snd_aw2

# replaced by p54pci
blacklist prism54

# replaced by b43 and ssb.
blacklist bcm43xx

# most apps now use garmin usb driver directly (Ubuntu: #114565)
blacklist garmin_gps

# replaced by asus-laptop (Ubuntu: #184721)
blacklist asus_acpi

# low-quality, just noise when being used for sound playback, causes
# hangs at desktop session start (Ubuntu: #246969)
blacklist snd_pcsp

# ugly and loud noise, getting on everyone's nerves; this should be done by a
# nice pulseaudio bing (Ubuntu: #77010)
blacklist pcspkr

# EDAC driver for amd76x clashes with the agp driver preventing the aperture
# from being initialised (Ubuntu: #297750). Blacklist so that the driver
# continues to build and is installable for the few cases where its
# really needed.
blacklist amd76x_edac

# added by rock 2021-11-26 for WIFI hardware-disable bug
blacklist acer_wmi

重启之后发现 WIFI 已经能够自动开启了，rfkill 结果也正常了。

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root@YSS:~# rfkill list all
0: phy0: Wireless LAN
	Soft blocked: no
	Hard blocked: no

参考链接

技术杂谈 modproberfkill