[pkg-wpa-devel] Bug#498600: Bug#498600: After resume, wpasupplicant sits idle

[Kel Modderman]

Hi Antony,

On Thursday 11 September 2008 22:03:11 Antony Gelberg wrote:
> Package: wpasupplicant
> Version: 0.6.4~git20080716.93ef879-1
> Severity: normal
> 
> Hi,
> 
> I have to say that this is a difficult problem to replicate, or should I say
> the workaround is not always the same.  I find that after suspending or
> hibernating my laptop, the wlan0 interface doesn't come back up properly.  It
> doesn't seem to matter whether or not I resume in the same SSID that I
> suspended in.

My hunch is it is very likely to be a problem related to the kernel
wifi driver/networking stack. Also check your dmesg buffer for interesting
messages from the kernel.

> 
> Here follows some output, taken a couple of minutes after resume, with my
> comments prefixed with ***.
> 
> Every 2.0s: ifconfig wlan0
> Sat Sep  6 11:57:11 2008
> 
> wlan0     Link encap:Ethernet  HWaddr 00:1f:3c:4b:70:1f
>           UP BROADCAST MULTICAST  MTU:1500  Metric:1
>           RX packets:675729 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:269129 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000
>           RX bytes:880049567 (839.2 MiB)  TX bytes:65980602 (62.9 MiB)
> 
> *** No IP address assigned.
> 
> very 2.0s: iwconfig wlan0 
> wlan0     IEEE 802.11  ESSID:"haslemere"
>           Mode:Managed  Frequency:2.462 GHz  Access Point: Not-Associated
>           Tx-Power=15 dBm
>           Retry min limit:7   RTS thr:off   Fragment thr=2352 B
>           Encryption key: ***munged [2]
>           Link Quality:0  Signal level:0  Noise level:0
>           Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
>           Tx excessive retries:0  Invalid misc:0   Missed beacon:0
> 
> *** No MAC address.
> 
> labrie:/home/antony# tail -f /var/log/wpa_supplicant.wlan0.log 
> Failed to initiate AP scan.
> Failed to initiate AP scan.
> Failed to initiate AP scan.
> Failed to initiate AP scan.
> Failed to initiate AP scan.
> Failed to initiate AP scan.
> Failed to initiate AP scan.
> Failed to initiate AP scan.
> Failed to initiate AP scan.
> Failed to initiate AP scan.
> 
> *** Self-explanatory.
> 
> Every 2.0s: ps ax |grep wlan0
> Sat Sep  6 11:59:47 2008
> 
> 28074 ?        Ss     0:00 /sbin/wpa_supplicant -W -B -P
> /var/run/wpa_supplicant.wlan0.pid -i wlan0 -D wext -q -f
> /var/log/wpa_supplicant.w
> 28125 ?        Ss     0:00 /sbin/wpa_cli -B -P /var/run/wpa_action.wlan0.pid
> -i wlan0 -p /var/run/wpa_supplicant -a /sbin/wpa_action
> 32259 pts/8    S+     0:00 watch ifconfig wlan0
> 32267 ?        Ss     0:00 avahi-autoipd: [wlan0] bound 169.254.3.212
> 32268 ?        Ss     0:00 avahi-autoipd: [wlan0] callout dispatcher
> 32277 pts/10   S+     0:00 watch iwconfig wlan0
> 32280 ?        Ss     0:00 dhclient3 -pf /var/run/dhclient.wlan0.pid -lf
> /var/lib/dhcp3/dhclient.wlan0.leases wlan0
> 32392 pts/9    S+     0:00 tail -f /var/log/wpa_supplicant.wlan0.log
> 32593 pts/14   S+     0:00 watch ps ax |grep wlan0
> 32629 pts/14   S+     0:00 sh -c ps ax |grep wlan0
> 32631 pts/14   S+     0:00 grep wlan0
> 
> *** wpa_supplicant and dhclient are running.
> 
> I tried reassociate in wpa_cli, and it associated with the AP, but still
> didn't receive an IP address via DHCP.  I then tried ifdown wlan0 && ifup
> wlan0, and I got:
> <2>Trying to associate with 00:14:bf:3d:a7:8e (SSID='haslemere' freq=2462 MHz)
> <2>CTRL-EVENT-SCAN-RESULTS 
> <2>Authentication with 00:14:bf:3d:a7:8e timed out.
> 
> Eventually things work, after ifdown wlan0, then waiting a minute or two, then
> ifup wlan0.  I wish I could be more specific about the recovery but it doesn't
> seem consistent - I'm not even 100% sure it's related to my ifdown and ifup
> commands.  Please let me know if you need any more information, I'll happily
> assist debugging if you give me a clue.
> 
> Lastly:
> # cat /etc/network/interfaces 
> # This file describes the network interfaces available on your system
> # and how to activate them. For more information, see interfaces(5).
> 
> # The loopback network interface
> auto lo
> iface lo inet loopback
> 
> # The primary network interface
> allow-hotplug eth0
> iface eth0 inet dhcp
> 
> auto wlan0
> iface wlan0 inet manual
>         wpa-driver wext
>         wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
> 
> iface default inet dhcp

Workarounds:

I have found it very reliable to have the network disconnected entering
suspend, and reconnected upon resuming. Otherwise, for me, the iwl* driver
seemed to resume still associated network but without meaningful network
connectivity.

The execution of such a hook depends on what power management software you are
using. On Debian the popular ones seem to be acpi-support or pm-utils. I
understand pm-utils pretty well, and have integrated a suspend/resume hook in a
package in personal archive:
http://sidux.net/kelmo/debian/pool/main/w/wpasupplicant/
(Disclaimer: be careful with packages not coming directly from Debian archive)

It installs a script to:
/etc/wpa_supplicant/action_wpa.sh

With symlink to script in pm-utils hook area:
/etc/pm/sleep.d/action_wpa

As long as you keep the default wpa_supplicant configuration option for
ctrl_interface (/var/run/wpa_supplicant/) this hook should be able to
disconnect all wpa-roam'ing interfaces as machine goes into sleep, and
reconnect on resume.

For acpi-support see: http://bugs.debian.org/390884 , I do not use or
understand acpi-support very well.

Thanks, Kel.