Fixing Raspberrypi’s WiFi Dropout Issues on EDUP EP-N8508GS

If you find your wifi 'drops out' from time to time, you can fix it by following procedures:

Create and edit a new file in /etc/modprobe.d/8192cu.conf

sudo vi /etc/modprobe.d/8192cu.conf
# Disable power saving (recommended)
options 8192cu rtw_power_mgnt=0 rtw_enusbss=0

Then reboot with sudo reboot. 結果反應在 /sys/module/8192cu/parameters/…

For details, please check "A Brief Introduction to RTL8192C driver Power Saving"

# In associated idle
rtw_power_mgnt=0|1|2
0 == disable power saving
1 == power saving on, minPS
2 == power saving on, maxPS

rtw_enusbss=0|1
0 == disable auto suspend
1 == enable auto suspend

rtw_hwpwrp_detect=0|1
0 == disable HW power pin detection
1 == enable HW power pin detection

# Under unassociated idle state
rtw_ips_mode=0|1
0 == low power, IPS_NORMAL
1 == higher power, IPS_LEVEL2

The conventional wisdom, because we're running our RPis as server systems not clients, is to set rtw_power_mgnt=0 and rtw_enusbss=0 to prevent the dongle going into power saving and to ignore the other two parms because they don't make any difference. If the server goes into power saving we'd need a process to wake it up. That's different from a client system where interaction from a keyboard user will trigger a request to wake up and associate the dongle.