Disable power management in Stretch

[VascoFerraz]

In Stretch, with predicables names active, on a RPi3 how can I disable the power management of the embedded wireless chip?

Thank you.

[DirkS]

AFAIK it's switched off by default.

[VascoFerraz]

AFAIK it's switched off by default.

After a fresh install of the following version:
Version: September 2017
Release date: 2017-09-07
Kernel version: 4.9
SHA-256: a64d742bc525b548f0435581fac5876b50a4e9ba1d1cd6433358b4ab6c7a770b

Also:
"/etc/network/interfaces" is empty.
I only added my network to the "/etc/wpa_supplicant/wpa_supplicant.conf"
Installed, samba, changed default ssh ports, edited fstab.

[DirkS]

Take a look at the log:

Code: Select all

pi@raspi07:~$ dmesg | grep brcm
[   10.622921] usbcore: registered new interface driver brcmfmac
[   10.750197] brcmfmac: Firmware version = wl0: Aug  7 2017 00:46:29 version 7.45.41.46 (r666254 CY) FWID 01-f8a78378
[   20.651866] brcmfmac: power management disabled

Due to some problems power management had to be switched off / disabled.
Right now I can't find relevant posts here on the forum or on the RPF github site.

[DirkS]

Found the firmware / kernel commit: https://github.com/raspberrypi/firmware ... a8d44af54b
And the forum topic: viewtopic.php?f=28&t=138312

[VascoFerraz]

You are right!

Code: Select all

[   26.801862] usbcore: registered new interface driver brcmfmac
[   26.942622] brcmfmac: Firmware version = wl0: Aug  7 2017 00:46:29 version 7.45.41.46 (r666254 CY) FWID 01-f8a78378
[   29.284947] brcmfmac: power management disabled
[16192.219005] brcmfmac: power management disabled

Then why I get my wlan0 disabled from time to time?

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wlan0   IEEE 802.11  ESSID:off/any
             Mode:Managed  Access Point: Not-Associated   Tx-Power=31 dBm
             Retry short limit:7   RTS thr:off   Fragment thr:off
             Power Management:on

[DirkS]

Then why I get my wlan0 disabled from time to time?

No idea.
I have a Zero W connected for days on end and have never noticed any dropouts.
(well, at least after I set our AP to a channel that was not hogged by all the other ones in the neighbourhood)

[VascoFerraz]

Then why I get my wlan0 disabled from time to time?

No idea.
I have a Zero W connected for days on end and have never noticed any dropouts.
(well, at least after I set our AP to a channel that was not hogged by all the other ones in the neighbourhood)

You are again right.

I set the router to another non hogged channel and since then I am not experiencing any disconnections from wlan0.

[rafnus]

Hi,

I am new with pi and if that can help you I found by this link
http://www.thelowercasew.com/disabling- ... ian-jessie

You just have to type
sudo iwconfig wlan0 power off

It should work as with the command sudo iwconfig shows me
Power Management : off

[amcdonley]

added to /etc/rc.local:

iwconfig wlan0 power off

resulted in my Stretch Pi3 onboard wifi power management being permanently off.

For my robot, this reduces the tx excessive retries by a factor of 10, and incoming ping Request timeouts by a factor of 2.

Code: Select all

Linux RWPi 4.9.41-v7+ #1023 SMP Tue Aug 8 16:00:15 BST 2017 armv7l GNU/Linux

[Ronaldlees]

added to /etc/rc.local:

iwconfig wlan0 power off

resulted in my Stretch Pi3 onboard wifi power management being permanently off.

For my robot, this reduces the tx excessive retries by a factor of 10, and incoming ping Request timeouts by a factor of 2.

Code: Select all

Linux RWPi 4.9.41-v7+ #1023 SMP Tue Aug 8 16:00:15 BST 2017 armv7l GNU/Linux

I wish i had a nickel for every post about a power-saving "feature" wasting people's time and causing things to break. My theory is that the companies that make hardware get a special tax break for putting "energy saving" modes into everything. Even though most of this stuff wouldn't save enough energy to warm a bird's nest for a day.

[DougieLawson]

For the RPF built-in Broadcom (aka Cypress) WiFi/BT there's no control for power management. It's disabled by the kernel and the only thing you're seeing is a bug in the iw / iwlist / iwconfig commands.

[grobi]

rc.local works for my Raspberry Pi Zero with Stretch 9.3. Thanks a lot