Date: Wed, 20 Jun 2012 11:43:05 +0530
From: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
To: Michael Leun <lkml20120218@newton.leun.net>
CC: Mohammed Shafi <shafi.wireless@gmail.com>,
	<linux-wireless@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: ath9k_htc: Every 2nd packet 1000ms delayed in recent kernels
Message-ID: <20120620061303.GA8738@vmraj-lnx.qca.qualcomm.com> (sfid-20120620_081220_984872_3031A916)
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On Wed, Jun 20, 2012 at 12:33:15AM +0200, Michael Leun wrote:
> On Tue, 19 Jun 2012 15:11:38 +0530
> Mohammed Shafi <shafi.wireless@gmail.com> wrote:
> 
> > Hi,
> > 
> > On Tue, Jun 19, 2012 at 12:21 PM, Michael Leun
> > <lkml20120218@newton.leun.net> wrote:
> > > Hi,
> > >
> > > ne-wlan1@elektra:/home/ml4> ping 192.168.2.1
> > > PING 192.168.2.1 (192.168.2.1) 56(84) bytes of data.
> > > 64 bytes from 192.168.2.1: icmp_seq=1 ttl=64 time=2010 ms
> > > 64 bytes from 192.168.2.1: icmp_seq=2 ttl=64 time=1011 ms
> > > 64 bytes from 192.168.2.1: icmp_seq=3 ttl=64 time=11.5 ms
> > > 64 bytes from 192.168.2.1: icmp_seq=4 ttl=64 time=1.12 ms
> > > 64 bytes from 192.168.2.1: icmp_seq=5 ttl=64 time=1002 ms
> > > 64 bytes from 192.168.2.1: icmp_seq=6 ttl=64 time=3.83 ms
> > > 64 bytes from 192.168.2.1: icmp_seq=7 ttl=64 time=1003 ms
> > > 64 bytes from 192.168.2.1: icmp_seq=8 ttl=64 time=4.10 ms
> > > 64 bytes from 192.168.2.1: icmp_seq=9 ttl=64 time=1003 ms
> > > 64 bytes from 192.168.2.1: icmp_seq=10 ttl=64 time=3.95 ms
> > > 64 bytes from 192.168.2.1: icmp_seq=11 ttl=64 time=1003 ms
> > > 64 bytes from 192.168.2.1: icmp_seq=12 ttl=64 time=3.78 ms
> > >
> > >
> > > Please note the additional delay of ~1000ms every 2nd packet. This
> > > is Kernel 3.4.3, have seen it in 3.4.2 also. Does NOT happen in
> > > 3.3.1.
> > >
> > > Is this Issue already known? If so, I can save the work bisecting...
> > 
> > looks like some one reported this bug in kernel bugzilla. would be
> > saving us lot of time
> > if you can bisect it!
> > 
> 
> 0775f9f90cdaf40fbf69b3192b3dddb2b3436f45 is the first bad commit
> commit 0775f9f90cdaf40fbf69b3192b3dddb2b3436f45
> Author: Johannes Berg <johannes.berg@intel.com>
> Date:   Thu Mar 8 15:02:06 2012 +0100
> 
>     mac80211: remove spurious BSSID change flag
> 
>     The BSSID has been set a lot earlier already and
>     didn't change again in ieee80211_set_associated().
> 
>     Signed-off-by: Johannes Berg <johannes.berg@intel.com>
>     Signed-off-by: John W. Linville <linville@tuxdriver.com>
> 
> :040000 040000 67a19a39e4b04c16921a3758ddd2362e02e81dd3 4a7cbd327b59345b83fa613f893770fbf44220bb M      net
> 
> Reverting 0775f9f90cdaf40fbf69b3192b3dddb2b3436f45 from 3.4.3 fixes the issue.
> 
Michael,

Thanks for the analysis. Can you please try with the attached patch without
reverting mac80211 change?

-Rajkumar