Arch Linux

Kotrfa

Member

Registered: 2012-10-25

Posts: 213

iwconfig doesn't really change power management

Hello,

I'm trying to "boost" my wifi by turning off power management. But it looks like it do not change anything at all. I tried different settings using iwconfig wlp1s0 power off|on|all and it changes in iwconfig, but it is unchanged in according files. Perhaps this snippet is better way to understand my problem:

nci@here ~ $ iwconfig wlp1s0          
wlp1s0    IEEE 802.11abgn  ESSID:"msie"  
          Mode:Managed  Frequency:2.462 GHz  Access Point: 00:**:95:84:**:B0   
          Bit Rate=19.5 Mb/s   Tx-Power=15 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality=40/70  Signal level=-70 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:423  Invalid misc:217   Missed beacon:0

nci@here ~ $ cat /sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0/net/wlp1s0/device/power/control /sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0/net/wlp1s0/power/control
on
auto
nci@here ~ $ sudo iwconfig wlp1s0 power on 
nci@here ~ $ cat /sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0/net/wlp1s0/device/power/control /sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0/net/wlp1s0/power/control
on
auto
nci@here ~ $ iwconfig wlp1s0
wlp1s0    IEEE 802.11abgn  ESSID:"msie"  
          Mode:Managed  Frequency:2.462 GHz  Access Point: 00:**:95:84:**:B0   
          Bit Rate=21.7 Mb/s   Tx-Power=15 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:on
          Link Quality=40/70  Signal level=-70 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:423  Invalid misc:218   Missed beacon:0

nci@here ~ $ sudo iwconfig wlp1s0 power all
nci@here ~ $ cat /sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0/net/wlp1s0/device/power/control /sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0/net/wlp1s0/power/control
on
auto
nci@here ~ $ iwconfig wlp1s0               
wlp1s0    IEEE 802.11abgn  ESSID:"msie"  
          Mode:Managed  Frequency:2.462 GHz  Access Point: 00:**:95:84:**:B0   
          Bit Rate=19.5 Mb/s   Tx-Power=15 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:on
          Link Quality=41/70  Signal level=-69 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:427  Invalid misc:218   Missed beacon:0

nci@here ~ $ sudo iwconfig wlp1s0 power off
nci@here ~ $ iwconfig wlp1s0               
wlp1s0    IEEE 802.11abgn  ESSID:"msie"  
          Mode:Managed  Frequency:2.462 GHz  Access Point: 00:**:95:84:**:B0   
          Bit Rate=21.7 Mb/s   Tx-Power=15 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality=41/70  Signal level=-69 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:427  Invalid misc:218   Missed beacon:0

nci@here ~ $ cat /sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0/net/wlp1s0/device/power/control /sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0/net/wlp1s0/power/control
on
auto

For networking I use only netctl. For power management (general) I use TLP and problem occurs even I stop it.

I have found same problem here https://bbs.archlinux.org/viewtopic.php?id=152067, but it is 2 years old and without answer.

Thank you

Last edited by Kotrfa (2014-05-06 07:20:03)

Rexilion

Member

Registered: 2013-12-23

Posts: 784

Re: iwconfig doesn't really change power management

iwconfig is an old command using an old interface of the kernel. I suggest you try iw.

---

fs/super.c : "Self-destruct in 5 seconds.  Have a nice day...\n",

Kotrfa

Member

Registered: 2012-10-25

Posts: 213

Re: iwconfig doesn't really change power management

Thank for reply. I didn't know about iw. But unfortunately it didn't help.

a@at ~ $ iw dev wlp1s0 get power_save                                                                                                                                    
Power save: off
a@at ~ $ cat /sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0/net/wlp1s0/device/power/control /sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0/net/wlp1s0/power/control
on
auto
a@at ~ $ sudo iw dev wlp1s0 set power_save on                                                                                                                                 
a@at ~ $ iw dev wlp1s0 get power_save                                                                                                                                    
Power save: on
a@at ~ $ cat /sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0/net/wlp1s0/device/power/control /sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0/net/wlp1s0/power/control
on
auto
a@at ~ $ sudo iw dev wlp1s0 set power_save off                                                                                                                                
a@at ~ $ iw dev wlp1s0 get power_save                                                                                                                                    
Power save: off
a@at ~ $ cat /sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0/net/wlp1s0/device/power/control /sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0/net/wlp1s0/power/control
on
auto

Rexilion

Member

Registered: 2013-12-23

Posts: 784

Re: iwconfig doesn't really change power management

I think (I'm not sure), it could be plausible we are mixing two seperate concepts of powermanagement.

The one iw controls is driver specific and implemented in the chipset. The other one, is part of the PCI specification.

I would not be surprised if the knobs regulate different methods of powersaving. Hence their apparent non existing relation.

---

fs/super.c : "Self-destruct in 5 seconds.  Have a nice day...\n",

Kotrfa

Member

Registered: 2012-10-25

Posts: 213

Re: iwconfig doesn't really change power management

Yes, it seems plausible... This behaviour is not only on my machine. I tried it on different Arch Linux device and also on Linux Mint - behaviour is same. Anyway, thank you

WonderWoofy

Member

From: Los Gatos, CA

Registered: 2012-05-19

Posts: 8,414

Re: iwconfig doesn't really change power management

Can you simply echo your desired value into the power/control file?  If so, then you can simply write a udev rule to turn it on if it is something you think should be on all the time.  Personally, on my laptop, it makes my Broadcom card run pretty horribly.  But I have heard of others with different HW where it seems to work just as well with it on or off.