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Author Topic: rtl8192cu power saving  (Read 5010 times)

Offline Rensie

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rtl8192cu power saving
« on: April 01, 2014, 02:15:00 PM »
I read that power saving was disabled in 5.2. Is there a command to re-enable it or is it hard coded into piCore? The unfortunate side effect for me is it makes my garage door opener not work due to the interference.  :'(

Offline bmarkus

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Re: rtl8192cu power saving
« Reply #1 on: April 01, 2014, 05:51:23 PM »
It is hardcoded. Enabling power saving it doesn't work according to forum members. I don't have such adaptor.
Béla
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"Amateur Radio: The First Technology-Based Social Network."

Offline Paul_123

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Re: rtl8192cu power saving
« Reply #2 on: April 01, 2014, 09:40:18 PM »
If you enable power save, the adapter will go to sleep and not wake up from any remote signal.   The problem is that the driver has not been accepting commands to enable/disable at time of loading the module......     

Offline bmarkus

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Re: rtl8192cu power saving
« Reply #3 on: April 02, 2014, 02:21:45 AM »
Checked 3.14.0 kernel, no change in driver.
Béla
Ham Radio callsign: HA5DI

"Amateur Radio: The First Technology-Based Social Network."

Offline Paul_123

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Re: rtl8192cu power saving
« Reply #4 on: April 02, 2014, 08:15:09 AM »
Is the only wifi device running on your router?   If there are other clients, the wifi from your router should equally cause problems.   

Have you tried changing the channel in your router wireless setup? 

Offline bmarkus

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Re: rtl8192cu power saving
« Reply #5 on: April 02, 2014, 10:13:52 AM »
Isn't garage opener a 443MHz or a 900MHz device? Don't think it is using the same frequency band as WiFi. There must be a generic Rf EMI issue, not related to WiFi.
« Last Edit: April 02, 2014, 10:16:23 AM by bmarkus »
Béla
Ham Radio callsign: HA5DI

"Amateur Radio: The First Technology-Based Social Network."

Offline Rensie

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Re: rtl8192cu power saving
« Reply #6 on: April 02, 2014, 01:58:01 PM »
My opener runs at 315MHz. As odd as it sounds, the problem immediately comes/goes with booting up/shutting down 5.2.1 (3.13.6). Zero problems with 5.2alpha1 (3.12.7). I have several other devices, phones, laptops, with no issues. I have tried 3 different channels on my access point. I realize it doesn't make much sense, but there it is. Honestly though, I am not going to lose any sleep over this. Maybe a future release will work for me.
« Last Edit: April 02, 2014, 02:00:12 PM by Rensie »

Offline Rensie

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Re: rtl8192cu power saving
« Reply #7 on: May 08, 2014, 12:50:45 PM »
Running 5.3rc3, all the weirdness with interference is gone. Thanks for fixing it, even though no one knows what it was.  :)

Offline bmarkus

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Re: rtl8192cu power saving
« Reply #8 on: May 08, 2014, 01:31:25 PM »
Running 5.3rc3, all the weirdness with interference is gone. Thanks for fixing it, even though no one knows what it was.  :)

Sounds good. Hope the same with rc4 and the final version. Still would be good to know more what the hell caused this issue :)
Béla
Ham Radio callsign: HA5DI

"Amateur Radio: The First Technology-Based Social Network."

Offline Wingspinner

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Re: rtl8192cu power saving
« Reply #9 on: June 17, 2014, 12:20:29 PM »
It's likely this has little to do with TC or related software or the wifi adapter and more to do with a weak or cheap power supply generating harmonics at a certain load level or the wifi adapter or RPi's on-board power supply circuitry generating harmonics due to excessive voltage drop. Unfortunately, it's a terrible design to use a micro-usb connector to supply power to the RPi. It's good enough until you start adding things like wifi adapters or overclocking it because the tiny little pins in the micro-usb connector are only rated at 1.8 amps. Couple that with all the polyfuses they use (polyfuses cause a significant voltage drop), a wifi adapter, a micro-USB cable with small wires that's a couple feet long, a heavy software load (especially with overclocking ) and the voltage drop starts causing the various on-board 5v to 3v power supplies to strain which can cause them to start producing nasty harmonics.

To avoid some of these issues you can build a cable that provides power directly to the GPIO power pins on the RPi and use a quality power supply of at least 2 amps

A tremendous amount of RPi odd-behavior are due to this power issue - it's a design deficiency. A good place to start reading is here: http://elinux.org/R-Pi_Troubleshooting#Troubleshooting_power_problems.

Cheers,
Ron