kern/163318: [ath] ath(4) stops working

Joel Dahl joel at
Tue Jan 17 19:00:30 UTC 2012

The following reply was made to PR kern/163318; it has been noted by GNATS.

From: Joel Dahl <joel at>
To: Adrian Chadd <adrian.chadd at>
Cc: bug-followup at
Subject: Re: kern/163318: [ath] ath(4) stops working
Date: Tue, 17 Jan 2012 19:50:57 +0100

 On 15-01-2012 12:10, Adrian Chadd wrote:
 > Hi,
 > So I want to establish whether the scan logic has hung, or whether the
 > scan logic has completed but left the interface hung.
 > How's your C? Would you mind doing some quick hacking:
 > * add a new variable in struct ath_softc, call it "sc_in_scan";
 > * set it to 1 in ath_scan_start (don't add any locks)
 > * set it to 0 in ath_scan_end (don't add any locks)
 > * edit the 'txagg' sysctl code in if_ath_sysctl.c to print out the
 > value of sc_in_scan;
 > Then verify that it's working as advertised:
 > * sysctl dev.ath.0.txagg=1 and check dmesg - sc_in_scan should be 0;
 > * do a manual scan (ifconfig wlan0 scan) and then redo the above
 > sysctl - it should be 1.
 Hm. I did the above changes and rebuilt my kernel. If I do sysctl
 dev.ath0.txagg=1, sc_in_scan is 0 just as expected. If I do a manual scan
 right after, it is still set to 0.
 ...or was I supposed to _only_ do ifconfig wlan0 scan once the interface has

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