Não é possível obter o IP com o Realtek 8821ae no Ubuntu 18.04

Question

Estou com problemas para me conectar ao Wi-Fi. Eu consigo ver as redes, mas não conecto.

Fatos

• Eu posso ver redes diferentes disponíveis, mas não consigo conectar
• Ubuntu dual 18.04 (Kernel 4.18) com o Windows 10
• Realtek 8821ae
• Lenovo Ideapad 320
• O hardware WiFi funciona no Windows 10

Eu tentei

• Praticamente todo o googling que você pode fazer sobre este assunto e questões relacionadas neste fórum e outros, por exemplo. stackexchange
• Atualizando o kernel do Linux
• Instalando novos drivers
• mudando para o WICD em vez do gerenciador de rede
• diferentes tipos de redes, seguras e não

De várias abordagens diferentes, vejo que o principal problema está em receber o endereço IP do servidor DHCP, já que o DHCPDISCOVER não retorna nada ou 'Nenhum DHCPOFFERS recebido'.

Algumas informações sobre o sistema:

$ sudo uname -a
Linux leon-Ubuntu 4.18.0-041800-lowlatency #201808122131 SMP PREEMPT Sun Aug 12 21:36:03 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

$ sudo lshw -C network
*-network                
   description: Wireless interface
   product: RTL8821AE 802.11ac PCIe Wireless Network Adapter
   vendor: Realtek Semiconductor Co., Ltd.
   physical id: 0
   bus info: pci@0000:01:00.0
   logical name: wlp1s0
   version: 00
   serial: b0:fc:36:2b:a5:2d
   width: 64 bits
   clock: 33MHz
   capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
   configuration: broadcast=yes driver=rtl8821ae driverversion=4.18.0-041800-lowlatency firmware=N/A latency=0 link=no multicast=yes wireless=IEEE 802.11
   resources: irq:38 ioport:2000(size=256) memory:e8c00000-e8c03fff

$ lsmod | grep rtl8821ae
rtl8821ae             233472  0
btcoexist             155648  1 rtl8821ae
rtl_pci                32768  1 rtl8821ae
rtlwifi                86016  3 rtl_pci,rtl8821ae,btcoexist
mac80211              802816  3 rtl_pci,rtl8821ae,rtlwifi

$ ifconfig
wlp1s0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
    ether b0:fc:36:2b:a5:2d  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

$ wconfig
wlp1s0    IEEE 802.11  ESSID:off/any  
      Mode:Managed  Access Point: Not-Associated   Tx-Power=20 dBm   
      Retry short limit:7   RTS thr=2347 B   Fragment thr:off
      Encryption key:off
      Power Management:on

$ iwconfig wlp1s0 essid <network>
$ dhclient -v wlp1s0
Internet Systems Consortium DHCP Client 4.3.5
Copyright 2004-2016 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Listening on LPF/wlp1s0/b0:fc:36:2b:a5:2d
Sending on   LPF/wlp1s0/b0:fc:36:2b:a5:2d
Sending on   Socket/fallback
DHCPDISCOVER on wlp1s0 to 255.255.255.255 port 67 interval 3 (xid=0x68e3751b)
DHCPDISCOVER on wlp1s0 to 255.255.255.255 port 67 interval 3
... etc
No DHCPOFFERS received.
No working leases in persistent database - sleeping.

$ dmesg # after network manager fails
[ 1283.623070] wlp1s0: authenticate with 68:72:51:42:67:36
[ 1283.623404] wlp1s0: send auth to 68:72:51:42:67:36 (try 1/3)
[ 1283.624978] wlp1s0: authenticated
[ 1283.630465] wlp1s0: associate with 68:72:51:42:67:36 (try 1/3)
[ 1283.642429] wlp1s0: RX AssocResp from 68:72:51:42:67:36 (capab=0x421 status=0 aid=2)
[ 1283.642726] wlp1s0: associated
[ 1283.643215] IPv6: ADDRCONF(NETDEV_CHANGE): wlp1s0: link becomes ready
[ 1329.024767] wlp1s0: deauthenticating from 68:72:51:42:67:36 by local choice (Reason: 3=DEAUTH_LEAVING)
[ 1329.064092] show_signal_msg: 29 callbacks suppressed
[ 1329.064095] dhcpcd[785]: segfault at 51 ip 0000559d9f6c26b0 sp 00007ffc2929e470 error 4 in dhcpcd5[559d9f6aa000+45000]
[ 1329.064102] Code: 85 e4 48 c7 44 24 14 00 00 00 00 48 8d 54 24 14 c7 44 24 1c 00 00 00 00 66 89 44 24 14 0f 85 d7 00 00 00 48 8b 87 b8 00 00 00 <44> 8b 28 48 8d 74 24 20 31 c0 b9 07 00 00 00 66 83 4b 06 04 48 89 
[ 1329.440910] IPv6: ADDRCONF(NETDEV_UP): wlp1s0: link is not ready

$ dmesg | grep -i firmware
[   14.517623] rtl8821ae: Using firmware rtlwifi/rtl8821aefw_29.bin
[   14.517631] rtl8821ae: Using firmware rtlwifi/rtl8821aefw_wowlan.bin

$ rfkill list all
0: ideapad_wlan: Wireless LAN
    Soft blocked: no
    Hard blocked: no
1: ideapad_bluetooth: Bluetooth
    Soft blocked: yes
    Hard blocked: no
2: phy0: Wireless LAN
    Soft blocked: no
    Hard blocked: no
3: hci0: Bluetooth
    Soft blocked: yes
    Hard blocked: no

Se você tiver quaisquer ponteiros, correções ou soluções, seria muito apreciado. E se você precisar de mais dados do sistema, por favor me avise.