Date: Mon, 11 Nov 2013 09:18:58 +0100 From: Stefan Farfeleder <stefanf@FreeBSD.org> To: Adrian Chadd <adrian@freebsd.org> Cc: Brandon Gooch <jamesbrandongooch@gmail.com>, freebsd-current <freebsd-current@freebsd.org> Subject: Re: iwn(4) hangs after r257133 Message-ID: <20131111081857.GA1809@mole.fafoe.narf.at> In-Reply-To: <CAJ-Vmon8E28qDHZ0NzTapob_YCRfDOikkYZGOjki=NA2LtwGdg@mail.gmail.com> References: <CALBk6yJf%2BZ_%2BF8kVPFOdQ%2B8UC3vBU3MZJGjkPfxeSkjSZ6FPbA@mail.gmail.com> <20131110121737.GA1834@mole.fafoe.narf.at> <CAJ-Vmom-57ZM0xsxLpL=prENzZ0j27jYNnMLk-_=HHONr3L8zA@mail.gmail.com> <20131110163340.GA1778@mole.fafoe.narf.at> <CAJ-VmonxB-to30Tkq9ad830FTRpbW2=cn9nuNzXHMK67jCuNgQ@mail.gmail.com> <20131110193421.GB1778@mole.fafoe.narf.at> <CAJ-Vmon8E28qDHZ0NzTapob_YCRfDOikkYZGOjki=NA2LtwGdg@mail.gmail.com>
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On Sun, Nov 10, 2013 at 02:01:12PM -0800, Adrian Chadd wrote: > Yes. So one of the.. unfortunately broken things in iwn is the ampdu tx > code doesn't do retransmits. So if amrr picks a rate that fails to transmit > everything, the driver doesn't retransmit them. It frees them. > > Now when amrr is enabled the hardware will retry at lower rates until > something succeeds. But it still doesn't retransmit things. I believe it > should be. > > So yes its more broken with Mrr disabled. But enabling mrr doesn't fix it. > It just makes it less broken. Someone needs to implement ampdu retransmit. > > The latest iwn code in head at least tells the rate selection code that a > total ampdu tx failure occured. This BTW is one of the hangs I fixed - if > you hit a point where you never successfully transmitted an ampdu at a rate > the rate would never be decreased. > > Now to be clear. I won't be in implementing ampdu retransmit. I'll maybe > fix last multi rate retry once the new hardware support is in. I would > really appreciate help here with these. Everyone with iwn hardware will > appreciate it :) In the mean time, wouldn't it make sense to disable ampdu tx in iwn then? Or to disallow the combination Mrr + ampdu? Stefan
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