I've been having problems with my wifi connection (rtl8821ae driver). I can stay connected for hours (as long as 6 hours) and then sometimes it just crashes and doesn't work on reboot. I have to wait until the next day.
sugar@hostname:~$ uname -v
#1 SMP Debian 3.16.7-ckt20-1+deb8u3 (2016-01-17)
sugar@hostname:~$ lspci -vnn | grep Network
04:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd.
RTL8821AE 802.11ac PCIe Wireless Network Adapter [10ec:8821]
sugar@hostname:~$ sudo iwconfig
eth0 no wireless extensions.
wlan0 IEEE 802.11abgn ESSID:"Bravotelecom_9947"
Mode:Managed Frequency:2.462 GHz Access Point: E8:CC:18:F7:81:50
Bit Rate=6.5 Mb/s Tx-Power=20 dBm
Retry short limit:7 RTS thr=2347 B Fragment thr:off
Encryption key:off
Power Management:off
Link Quality=70/70 Signal level=-24 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:1 Missed beacon:0
lo no wireless extensions.
I've tried to enable power management and then turn it off (even though it shows it is already turned off):
sugar@hostname:~$ sudo modprobe rtl8821ae swlps=1
sugar@hostname:~$ sudo iwconfig wlan0 power off
Error for wireless request "Set Power Management" (8B2C) :
SET failed on device wlan0 ; Operation not supported.
But I keep getting this error... anyway I don't think this is the problem.
I've also tried:
rfkill unblock -all
But nothing was soft or hard blocked to start with so no differences. My router is configured for IPv4 (not IPv6), and supports channels in 2 GHz and 5 GHz band. I have noticed that my Network Adapter switches between these two frequencies... sometimes I'm connected with low band and other times high band.
I will post the journalctl entries next time it crashes because I don't have them right now.