Return-path: Received: from charlotte.tuxdriver.com ([70.61.120.58]:49491 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755015Ab1DHRaW (ORCPT ); Fri, 8 Apr 2011 13:30:22 -0400 Date: Fri, 8 Apr 2011 13:17:48 -0400 From: "John W. Linville" To: Felix Fietkau Cc: linux-wireless , "Luis R. Rodriguez" Subject: Re: [PATCH 2.6.39 v2] ath9k_hw: fix stopping rx DMA during resets Message-ID: <20110408171747.GA2550@tuxdriver.com> References: <4D9EFA5F.3040900@openwrt.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <4D9EFA5F.3040900@openwrt.org> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Fri, Apr 08, 2011 at 02:06:55PM +0200, Felix Fietkau wrote: > During PHY errors, the MAC can sometimes fail to enter an idle state on older > hardware (before AR9380) after an rx stop has been requested. > > This typically shows up in the kernel log with messages like these: > > ath: Could not stop RX, we could be confusing the DMA engine when we start RX up > ------------[ cut here ]------------ > WARNING: at drivers/net/wireless/ath/ath9k/recv.c:504 ath_stoprecv+0xcc/0xf0 [ath9k]() > Call Trace: > [<8023f0e8>] dump_stack+0x8/0x34 > [<80075050>] warn_slowpath_common+0x78/0xa4 > [<80075094>] warn_slowpath_null+0x18/0x24 > [<80d66d60>] ath_stoprecv+0xcc/0xf0 [ath9k] > [<80d642cc>] ath_set_channel+0xbc/0x270 [ath9k] > [<80d65254>] ath_radio_disable+0x4a4/0x7fc [ath9k] > > When this happens, the state that the MAC enters is easy to identify and > does not result in bogus DMA traffic, however to ensure a working state > after a channel change, the hardware should still be reset. > > This patch adds detection for this specific MAC state, after which the above > warnings completely disappear in my tests. > > Signed-off-by: Felix Fietkau > Cc: stable@kernel.org > Cc: Kyungwan Nam > > --- > v2: remove a redundant ath9k_hw_stopdmarecv call, print the MAC DMA state when the error still occurs > > drivers/net/wireless/ath/ath9k/hw.c | 9 --------- > drivers/net/wireless/ath/ath9k/mac.c | 25 ++++++++++++++++++++++--- > drivers/net/wireless/ath/ath9k/mac.h | 2 +- > drivers/net/wireless/ath/ath9k/recv.c | 6 +++--- > 4 files changed, 26 insertions(+), 16 deletions(-) > > diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c > index 1b5bd13..c8a2d0d 100644 > --- a/drivers/net/wireless/ath/ath9k/hw.c > +++ b/drivers/net/wireless/ath/ath9k/hw.c > @@ -1249,15 +1249,6 @@ int ath9k_hw_reset(struct ath_hw *ah, struct ath9k_channel *chan, > ah->txchainmask = common->tx_chainmask; > ah->rxchainmask = common->rx_chainmask; > - if ((common->bus_ops->ath_bus_type != ATH_USB) && !ah->chip_fullsleep) { This patch seems a bit busted...? I tried to fix it up manually but the errors just keep coming... -- John W. Linville Someday the world will need a hero, and you linville@tuxdriver.com might be all we have. Be ready.