evil_dan2wik
Posts: 18
Joined: Sun Mar 23, 2014 3:20 am

RTL8188cus wifi dongle sleeping

Mon Mar 24, 2014 7:35 am

So I have a RTL8188cus wifi dongle and it goes to sleep if nothing is sent for around a minute and then it wakes up after about 25 seconds of my trying to access it again through ssh. If I have an idle ssh session open, it will time out when I try to use it again unless it is running "top". Is there a way to disable sleep mode?

MrEngman
Posts: 4140
Joined: Fri Feb 03, 2012 2:17 pm
Location: Southampton, UK

Re: RTL8188cus wifi dongle sleeping

Mon Mar 24, 2014 9:03 am

A favourite issue giving this sort of problem is a power supply that supplies too little current. Try a power supply with larger current capacity if you can.

Otherwise try this. Make a file /etc/modprobe.d/8192cu.conf using command

Code: Select all

sudo nano /etc/modprobe.d/8192cu.conf
and in the file add the lines

Code: Select all

# Disable power management
options 8192cu rtw_power_mgnt=0 rtw_enusbss=0
After saving the file using key strokes Cntl-X, Y, Enter, reboot to get it to come into effect.

The rtl8188us wifi driver is compiled with a limited power management enabled which may be causing your problem. The above file turns off the power management for rtl8188cus devices.


MrEngman
Simplicity is a prerequisite for reliability. Edsger W. Dijkstra

Please post ALL technical questions on the forum. Please Do Not send private messages.

evil_dan2wik
Posts: 18
Joined: Sun Mar 23, 2014 3:20 am

Re: RTL8188cus wifi dongle sleeping

Mon Mar 24, 2014 11:35 am

I just made the file, And the power supply I use is a few different ones depending on where I am.

I use my laptop, A pocket power bank, The USB port on the back of the TV and a USB phone charger. My laptop and the power bank give 5.09v without the pi and around 5.02v with the pi. The TV gives 4.94v and drops to 4.92v with the pi. and the phone charger gives 5.23-5.29v which drops down to 4.72-4.79v with pi.

The pi runs fine with all of them except when plugging the wifi chip in when on the phone charger causes a reboot.

evil_dan2wik
Posts: 18
Joined: Sun Mar 23, 2014 3:20 am

Re: RTL8188cus wifi dongle sleeping

Mon Mar 24, 2014 12:04 pm

It doesn't seem to become completely unresponsive now. But it randomly spikes with latency of up to 730ms with average jitter at 137ms. Removing the file again gives 8ms latency with jitter of 3ms but I still have the problem of keeping the link alive.

Return to “Troubleshooting”