[rt2x00-users] [bugzilla-daemon at bugzilla.kernel.org: [Bug 42828] rt2800pci unstable - chokes after too much I/O]

Andreas Hartmann andihartmann at 01019freenet.de
Wed Nov 14 05:47:26 AEDT 2012


Hello Stanislaw,

Stanislaw Gruszka wrote:
> On Tue, Nov 06, 2012 at 09:52:03PM +0100, Andreas Hartmann wrote:
>> Stanislaw Gruszka wrote:
>>> On Thu, Oct 18, 2012 at 08:48:22PM +0200, Andreas Hartmann wrote:
>>>>> any insight on commit be03d4a45c09ee5100d3aaaedd087f19bc20d01f
>>>>> regression described in kernel.org bug 42828 ?
>>>>
>>>> Anyway, I retested with compat-wireless-3.5 rc5 and I can see a complete
>>>> hanging connection after 3s of running netperf with
>>>> 0011-Revert-rt2x00-Don-t-let-mac80211-send-a-BAR-when-an-.patch (2.4
>>>> GHz, 40MHz) - the original problem and the reason for the patch.
>>>
>>> Andreas, 
>>>
>>> can you revert commit be03d4a45c09ee5100d3aaaedd087f19bc20d01f and test
>>> below patch, does AP mode also hungs with that?
>>
>> The patch not only hangs up the connection, but the complete machine :-(
> 
> Ok, I'm voting for reverting both commits:
> 
> commit be03d4a45c09ee5100d3aaaedd087f19bc20d01f
> Author: Andreas Hartmann <andihartmann at 01019freenet.de>
> Date:   Tue Apr 17 00:25:28 2012 +0200
> 
>     rt2x00: Don't let mac80211 send a BAR when an AMPDU subframe fails
> 
> commit f0425beda4d404a6e751439b562100b902ba9c98
> Author: Felix Fietkau <nbd at openwrt.org>
> Date:   Sun Aug 28 21:11:01 2011 +0200
> 
>     mac80211: retry sending failed BAR frames later instead of tearing down aggr
> 
> f0425beda is causing troubles on rt2800 because that hardware do not
> report BAR ack (perhaps because it is acked by BA frame not ACK frame),
> so we constantly send BAR frames with the same SSN. This can be hardware
> problem, but also if we can jump into that simulation if remote station
> will not ack BAR frames or due to noisy radio conditions.

I did a short test (half an hour, middle receiving conditions, AP) with
the above mentioned patches removed but w/o your patch applied at the
bottom. At a first glance, the line is a little bit more bumpy, but this
could be chance, too. I have to do some more tests at the weekend (with
the patch at the bottom applied, too).

> Felix, are you ok with revert of f0425beda ? I think posting BAR at
> robust rate (see below patch) could address the problem, which commit
> f0425beda solves.
> 
> Thanks
> Stanislaw
> 
> diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
> index 3195a63..63c5d9e 100644
> --- a/net/mac80211/agg-tx.c
> +++ b/net/mac80211/agg-tx.c
> @@ -136,7 +136,8 @@ void ieee80211_send_bar(struct ieee80211_vif *vif, u8 *ra, u16 tid, u16 ssn)
>  	bar->start_seq_num = cpu_to_le16(ssn);
>  
>  	IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT |
> -					IEEE80211_TX_CTL_REQ_TX_STATUS;
> +					IEEE80211_TX_CTL_REQ_TX_STATUS |
> +					IEEE80211_TX_CTL_USE_MINRATE;
>  	ieee80211_tx_skb_tid(sdata, skb, tid);
>  }
>  EXPORT_SYMBOL(ieee80211_send_bar);
> 

Thanks,
kind regards,
Andreas Hartmann




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