wpa_supplicant 0.7.3 slow to associate, 0.6.10 is ok

Koen Beel koen.beel.barco at gmail.com
Mon Aug 13 06:13:22 EDT 2012

On Fri, Aug 10, 2012 at 5:16 PM, Jouni Malinen <j at w1.fi> wrote:
> On Fri, Aug 10, 2012 at 04:57:28PM +0200, Koen Beel wrote:
>> In a product we are building, we are using wpa_supplicant to connect
>> to a WPA2-PSK secured AP and are experiencing pretty low association
>> times when using wpa_supplicant 0.7.3.
>> After a very large number of test cylces (many 100's), we see that the
>> association time is somewhere between 8 and 10 seconds.
> Which driver are you using? Are you using ap_scan=2 or 1 (default)? Is
> the card dual band (i.e., will it scan both 2.4 GHz and 5 GHz channels)?

We are using ap_scan = 1 (default). Don't think the ap_scan=2 is
supported by the driver.
The card is a dual band card from Redpine Signals. The driver is
proprietary. We do have the source code and can check things in the
driver if needed, but we cannot share the source code itself.

>> We have also done some test using the 0.6.10 version and here we see
>> that the association time is only between 1 and 2 seconds.

One thing I did forget to mention is this. With the 0.6.10 association
time is only 1 - 2 seconds, but from time to time it takes about 20
seconds. We don't know the reason for this.

Also when reviewing the association times of the 0.7.3, we see that
some of the test cycles it takes about 10 extra to finish association.
So for a small number of test cycles we see that the association time
is about 18 - 20 seconds instead of 8 - 10.
And for an even smaller number of test cycles we see 28 - 30 seconds.

> Please send debug logs with timestamps (-dt on command line) from both
> 0.6.10 and 0.7.3.

See attachment. (in separate e-mails due to file size limit on ML)

On strange thing we see in the logs for 0.7.3 (but not in the logs of
0.6.10) is the following:

58.697437: Scan timeout - try to get results
ioctl[SIOCGIWSCAN]: Resource temporarily unavailable
58.697906: Failed to get scan results
58.698000: Failed to get scan results - try scanning again
58.698125: Setting scan request: 1 sec 0 usec
59.698750: Starting AP scan for wildcard SSID
ioctl[SIOCSIWSCAN]: Resource temporarily unavailable
59.699156: Scan requested (ret=-1) - scan timeout 5 seconds
59.699281: Failed to initiate AP scan.
59.699406: Setting scan request: 1 sec 0 usec

>> We are using WEXT driver, and using the config file in attachment.
> Moving to nl80211-based interface would speed up things considerably for
> many drivers..

afaik our driver does not support the nl80211 interface.

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