Return-path: Received: from nbd.name ([46.4.11.11]:36723 "EHLO nbd.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756962Ab1DHSAq (ORCPT ); Fri, 8 Apr 2011 14:00:46 -0400 Message-ID: <4D9F4D49.5060300@openwrt.org> Date: Fri, 08 Apr 2011 20:00:41 +0200 From: Felix Fietkau MIME-Version: 1.0 To: "John W. Linville" CC: linux-wireless , "Luis R. Rodriguez" Subject: Re: [PATCH 2.6.39 v2] ath9k_hw: fix stopping rx DMA during resets References: <4D9EFA5F.3040900@openwrt.org> <20110408171747.GA2550@tuxdriver.com> In-Reply-To: <20110408171747.GA2550@tuxdriver.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 2011-04-08 7:17 PM, John W. Linville wrote: > 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... Hm, you're right. No idea what my email client did there. I'll resend... - Felix