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Ticket #1258 (new defect)

Opened 15 years ago

Last modified 15 years ago

Background scan never ends; continuously in Power Save mode.

Reported by: dasnake@gmail.com Assigned to:
Priority: major Milestone:
Component: madwifi: 802.11 stack Version:
Keywords: Cc:
Patch is attached: 0 Pending:

Description

Hello, I'm experiencing connection problems with the latest svn version of the driver and 2.6.20.6 kernel.

I'm connected to a not encrypted hidden essid AP, not under my control.

My kernel is:

Linux apratula 2.6.20.6 #1 PREEMPT Tue Apr 10 14:18:31 CEST 2007 i686 GNU/Linux

Driver is:

Apr 10 17:46:56 localhost kernel: ath_hal: 0.9.18.0 (AR5210, AR5211, AR5212, RF5
111, RF5112, RF2413, RF5413)
Apr 10 17:46:56 localhost kernel: wlan: 0.8.4.2 (svn r2267)
Apr 10 17:46:56 localhost kernel: ath_pci: 0.9.4.5 (svn r2267)
Apr 10 17:46:56 localhost kernel: ACPI: PCI Interrupt Link [LNKE] enabled at IRQ
 10
Apr 10 17:46:56 localhost kernel: ACPI: PCI Interrupt 0000:02:01.0[A] -> Link [L
NKE] -> GSI 10 (level, low) -> IRQ 10
Apr 10 17:46:56 localhost kernel: ath_rate_sample: 1.2 (svn r2267)
Apr 10 17:46:56 localhost kernel: wifi0: 11a rates: 6Mbps 9Mbps 12Mbps 18Mbps 24
Mbps 36Mbps 48Mbps 54Mbps
Apr 10 17:46:56 localhost kernel: wifi0: 11b rates: 1Mbps 2Mbps 5.5Mbps 11Mbps
Apr 10 17:46:56 localhost kernel: wifi0: 11g rates: 1Mbps 2Mbps 5.5Mbps 11Mbps 6
Mbps 9Mbps 12Mbps 18Mbps 24Mbps 36Mbps 48Mbps 54Mbps
Apr 10 17:46:56 localhost kernel: wifi0: H/W encryption support: WEP AES AES_CCM
 TKIP
Apr 10 17:46:56 localhost kernel: wifi0: mac 5.9 phy 4.3 radio 3.6
Apr 10 17:46:56 localhost kernel: wifi0: Use hw queue 1 for WME_AC_BE traffic
Apr 10 17:46:56 localhost kernel: wifi0: Use hw queue 0 for WME_AC_BK traffic
Apr 10 17:46:56 localhost kernel: wifi0: Use hw queue 2 for WME_AC_VI traffic
Apr 10 17:46:56 localhost kernel: wifi0: Use hw queue 3 for WME_AC_VO traffic
Apr 10 17:46:56 localhost kernel: wifi0: Use hw queue 8 for CAB traffic
Apr 10 17:46:56 localhost kernel: wifi0: Use hw queue 9 for beacons
Apr 10 17:46:56 localhost kernel: wifi0: Atheros 5212: mem=0xe0200000, irq=10

The symptom is that after a certain random time connected and properly working the link suddendly goes mute: no packets on tcpdump, no evident errors, nothing in the log.

I've narrowed down the problem to a power save problem. I've noticed, enabling debug, that when the connection goes mute this is happening:

Apr 11 11:50:54 localhost kernel: ath0: [00:0e:84:ab:0d:20] sta power save mode
on
Apr 11 11:50:54 localhost kernel: ath0: [00:0e:84:ab:0d:20] save frame, 1 now qu
eued
Apr 11 11:50:54 localhost kernel: ath0: [00:0e:84:ab:0d:20] save frame, 2 now qu
eued

And so on, until:

Apr 11 12:08:47 localhost kernel: ath0: [00:0e:84:ab:0d:20] pwr save q overflow,
 drops 1 (size 50)
Apr 11 12:08:48 localhost kernel: ath0: [00:0e:84:ab:0d:20] pwr save q overflow,
 drops 2 (size 50)
Apr 11 12:08:52 localhost kernel: ath0: [00:0e:84:ab:0d:20] pwr save q overflow,
 drops 3 (size 50)

And so on.

I've tried with:

apratula:~# iwconfig ath0 power off

But nothing happens. Notice that:

apratula:~# iwconfig ath0 power on 
Error for wireless request "Set Power Management" (8B2C) :
    SET failed on device ath0 ; Operation not supported.

My wireless tools are v28.

The only way I found to wake from the power save state is to initiate a scanning with iwlist ath0 scan. That way the sta exit the power save mode and the connection return to recive packets, but after some random time it fall back into power save mode.

I've noticed that if there's traffic, expecially traffic with many connections like torrent the link stays up a lot longer. From few minutes without traffic to few hours with traffic.

Any clue? I forgot some useful information?

Change History

04/12/07 00:33:36 changed by mentor

Background scanning enables Power Save mode, and then changes the radio channel to listen for APs, and then returns to the original channel, disables Power Save mode and continues to normal operation.

You can disable BG scanning with iwpriv. However, the scan should always end eventually, so this is a bug.

04/12/07 00:48:56 changed by mentor

  • summary changed from pwr save q overflow to Background scan never ends; continuously in Power Save mode..

04/12/07 10:26:57 changed by dasnake

I'm trying with bg scanning off and seems to have solved the issue, but I wonder why some kind of traffic, ie torrent, solve anyway the problem.

05/15/07 01:16:07 changed by mentor

r2330 may have fixed this issue; please could you test it?