From: "Gordon, Charles" <Charles.Gordon@digi.com>
To: "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
Date: Wed, 26 May 2010 06:57:31 -0500
Subject: Is there a bug in 2.6.29-rc8 support of Ad-Hoc mode?
Message-ID: <8DCC153EAFE67A4B990A840E829F704B017C658D5E6C@mtk-sms-exch01.digi.com>
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Sender: linux-wireless-owner@vger.kernel.org

I am trying to get a driver I'm developing to work with Ad-Hoc mode on
Linux 2.6.29-rc8. ?I am running into a problem. ?I have traced it down
to the routine ieee80211_scan_work. ?I use the following commands to
start Ad-Hoc mode:

ifconfig wlan0 down
iwconfig wlan0 mode Ad-Hoc essid "AdHocID"
ifconfig wlan0 up

What happens is that the iwconfig command starts a scan for other PCs
using the AdHocID before the second ifconfig command is executed
(while the interface is still down). ?When ieee80211_scan_work is
executed, it bails out at this statement:

? ? ? ?/*
? ? ? ? * Avoid re-scheduling when the sdata is going away.
? ? ? ? */
? ? ? ?if (!netif_running(sdata->dev))
? ? ? ? ? ? ? ?return;

This aborts the scan, but leaves local->sw_scanning set. ?This
prevents future scans from running. ?When ieee80211_start_scan
executes it bails out at this statement:

? ? ? ?if (local->sw_scanning || local->hw_scanning) {
? ? ? ? ? ? ? ?if (local->scan_sdata == scan_sdata)
? ? ? ? ? ? ? ? ? ? ? ?return 0;
? ? ? ? ? ? ? ?return -EBUSY;
? ? ? ?}

Can someone either confirm that this is a known problem with
2.6.28-rc8, or tell me what my driver could be doing to cause this
problem?

Thanks for any help you can provide.