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From: "Luis R. Rodriguez" <mcgrof@gmail.com>
To: "Björn Smedman" <bjorn.smedman@venatech.se>
Cc: Ben Gamari <bgamari@gmail.com>,
	ath9k-devel@lists.ath9k.org,
	linux-wireless <linux-wireless@vger.kernel.org>
Subject: Re: [ath9k-devel] ath9k: race conditions in dma
Date: Mon, 1 Nov 2010 09:44:15 -0700	[thread overview]
Message-ID: <AANLkTimBf6PRdTNUpx1HLu6Q70onHi3YhqKOYQ2Rk-yF@mail.gmail.com> (raw)
In-Reply-To: <AANLkTin1oXb8mkyxZgn5jEy7FJF9BPpiuJ1Q7j9XCDYz@mail.gmail.com>

2010/11/1 Björn Smedman <bjorn.smedman@venatech.se>:
> On Mon, Nov 1, 2010 at 4:43 PM, Ben Gamari <bgamari@gmail.com> wrote:
>> On Mon, 1 Nov 2010 16:17:23 +0100, Björn Smedman <bjorn.smedman@venatech.se> wrote:
>>> Hi all,
>>>
>>> I have an application that creates and destroys a lot of ap vifs and
>>> does a lot of monitor frame injection. The recent ath9k rx locking
>>> fixes have helped with stability in this use-case but there still
>>> seems to be some tx/beacon related race condition(s). These manifests
>>> themselves as follows on an AR913x based router running
>>> compat-wireless-2010-10-19 (with locking fixes etc from openwrt):
>>>
>>> 1. TX DMA hangs under simultaneous high RX and TX load
>>> 2. TX is completely hung but chip is never reset
>>
>> I have also observed both of these behaviors with just a standard
>> hostapd single VIF configuration. Quite annoying. It seems to be better
>> with recent wireless-testing trees.
>>
>> - Ben
>
> The next thing that looks racy to me is ath_beacon_alloc() vs
> ath_beacon_tasklet() in beacon.c. Beacon queue TX DMA is always
> stopped in main.c before calling ath_beacon_alloc() but
> ath_beacon_tasklet() is scheduled when we get an SWBA interrupt. My
> guess is that these keep coming even if we stop TX DMA on the beacon
> queue, no?

My TX PCU patches for ath9k are not merged yet, try those or wait
until John merges them.

  Luis

WARNING: multiple messages have this Message-ID (diff)
From: Luis R. Rodriguez <mcgrof@gmail.com>
To: ath9k-devel@lists.ath9k.org
Subject: [ath9k-devel] ath9k: race conditions in dma
Date: Mon, 1 Nov 2010 09:44:15 -0700	[thread overview]
Message-ID: <AANLkTimBf6PRdTNUpx1HLu6Q70onHi3YhqKOYQ2Rk-yF@mail.gmail.com> (raw)
In-Reply-To: <AANLkTin1oXb8mkyxZgn5jEy7FJF9BPpiuJ1Q7j9XCDYz@mail.gmail.com>

2010/11/1 Bj?rn Smedman <bjorn.smedman@venatech.se>:
> On Mon, Nov 1, 2010 at 4:43 PM, Ben Gamari <bgamari@gmail.com> wrote:
>> On Mon, 1 Nov 2010 16:17:23 +0100, Bj?rn Smedman <bjorn.smedman@venatech.se> wrote:
>>> Hi all,
>>>
>>> I have an application that creates and destroys a lot of ap vifs and
>>> does a lot of monitor frame injection. The recent ath9k rx locking
>>> fixes have helped with stability in this use-case but there still
>>> seems to be some tx/beacon related race condition(s). These manifests
>>> themselves as follows on an AR913x based router running
>>> compat-wireless-2010-10-19 (with locking fixes etc from openwrt):
>>>
>>> 1. TX DMA hangs under simultaneous high RX and TX load
>>> 2. TX is completely hung but chip is never reset
>>
>> I have also observed both of these behaviors with just a standard
>> hostapd single VIF configuration. Quite annoying. It seems to be better
>> with recent wireless-testing trees.
>>
>> - Ben
>
> The next thing that looks racy to me is ath_beacon_alloc() vs
> ath_beacon_tasklet() in beacon.c. Beacon queue TX DMA is always
> stopped in main.c before calling ath_beacon_alloc() but
> ath_beacon_tasklet() is scheduled when we get an SWBA interrupt. My
> guess is that these keep coming even if we stop TX DMA on the beacon
> queue, no?

My TX PCU patches for ath9k are not merged yet, try those or wait
until John merges them.

  Luis

  reply	other threads:[~2010-11-01 16:44 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-01 15:17 ath9k: race conditions in dma Björn Smedman
2010-11-01 15:17 ` [ath9k-devel] " Björn Smedman
2010-11-01 15:43 ` Ben Gamari
2010-11-01 15:43   ` Ben Gamari
2010-11-01 15:50   ` Björn Smedman
2010-11-01 15:50     ` Björn Smedman
2010-11-01 23:12     ` Peter Stuge
2010-11-01 23:12       ` Peter Stuge
2010-11-01 16:20   ` Björn Smedman
2010-11-01 16:20     ` Björn Smedman
2010-11-01 16:39   ` Björn Smedman
2010-11-01 16:39     ` Björn Smedman
2010-11-01 16:44     ` Luis R. Rodriguez [this message]
2010-11-01 16:44       ` Luis R. Rodriguez
2010-11-01 16:52       ` Felix Fietkau
2010-11-01 16:52         ` Felix Fietkau
2010-11-01 17:12         ` Björn Smedman
2010-11-01 17:12           ` Björn Smedman
2010-11-02 16:55   ` Björn Smedman
2010-11-02 16:55     ` Björn Smedman
2010-11-03 16:41     ` Björn Smedman
2010-11-03 16:41       ` Björn Smedman
2010-11-03 17:47     ` Ben Gamari
2010-11-03 17:47       ` Ben Gamari

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