Return-path: Received: from mail.candelatech.com ([208.74.158.172]:44173 "EHLO ns3.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754515Ab0LFU2l (ORCPT ); Mon, 6 Dec 2010 15:28:41 -0500 Message-ID: <4CFD4773.6020304@candelatech.com> Date: Mon, 06 Dec 2010 12:28:35 -0800 From: Ben Greear MIME-Version: 1.0 To: "Luis R. Rodriguez" CC: Luis Rodriguez , Felix Fietkau , "ath9k-devel@lists.ath9k.org" , "linux-wireless@vger.kernel.org" Subject: Re: [ath9k-devel] Script to crash ath9k with DMA errors. References: <4CF44543.9070605@candelatech.com> <20101130004424.GC1901@tux> <4CF6D8C8.2000308@candelatech.com> <4CF8A6DE.4020804@candelatech.com> <4CFAFBE1.3080505@openwrt.org> <4CFB20BA.5090300@candelatech.com> <20101206193600.GC21442@tux> <4CFD3DE3.4000207@candelatech.com> <20101206195313.GE21442@tux> <20101206195348.GF21442@tux> In-Reply-To: <20101206195348.GF21442@tux> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 12/06/2010 11:53 AM, Luis R. Rodriguez wrote: > On Mon, Dec 06, 2010 at 11:53:13AM -0800, Luis Rodriguez wrote: >> On Mon, Dec 06, 2010 at 11:47:47AM -0800, Ben Greear wrote: >>> On 12/06/2010 11:36 AM, Luis R. Rodriguez wrote: >>> >>>> Can you clarify the status of this issue. It remains unclear to me from >>>> your above description how things are going. As I read it some things >>>> look OK now but you still get a warning. >>> >>> Ok, since you asked :) >>> >>> I worked on this over the weekend and this morning. I had all sorts of >>> issues until I realized that I had one STA with non-configured SSID. >>> It sometimes connected to one /a AP and the other STAs attempted to connect >>> to another /n (on entirely different band) AP. I basically got zero stations associated for any length >>> of time due to constant channel switching. No crashes, but lots of >>> warnings about DMA failing to stop. >>> >>> Now..I've fixed this configuration issue (and adding steps to help prevent this mis-configuration >>> again). >>> >>> With 16 properly configured non-encrypted stations, running with wpa-supplicant >>> with netlink driver& sharing scan results, the interfaces quickly associate. >>> >>> However, I do continue to see DMA warnings such as these (I had picked up my >>> portable phone, and it knocked all the interfaces offline ..here >>> they are coming back up after I hung up the phone). >>> >>> Please note that I ported Felix's 2.6.37 patch he posted this morning >>> to wireless-testing and have applied it. >>> >>> I'm highly tempted to just make that a WARN_ON_ONCE so at least my logs >>> aren't spammed so heavily with the recv.c:531 DMA warning. >> >> You can send this change upstream as well. > > Also, feel free to limit the number of STAs you can have up > physically by setting this to a number you bless yourself. I have a feeling there is no hard limit..but if I do find one, I'll cook up a patch. Probably not many of us ever going to push anywhere near what I'm trying, and folks like me can limit in user-space if wanted... I'll do up the warn-on-once patch shortly. By the way, would you consider this channel-change suppression patch, or something similar? -------------------- drivers/net/wireless/ath/ath9k/main.c -------------------- index f026a03..6c1c43b 100644 @@ -1605,6 +1605,16 @@ static int ath9k_config(struct ieee80211_hw *hw, u32 changed) else sc->sc_flags &= ~SC_OP_OFFCHANNEL; + /* If channels & HT are the same, then don't actually do anything. + */ + if ((sc->sc_ah->curchan == &sc->sc_ah->channels[pos]) && + (aphy->chan_is_ht == conf_is_ht(conf))) { + ath_print(common, ATH_DBG_CONFIG, + "Skip Set channel: %d MHz, already there.\n", + curchan->center_freq); + goto skip_chan_change; + } + if (aphy->state == ATH_WIPHY_SCAN || aphy->state == ATH_WIPHY_ACTIVE) ath9k_wiphy_pause_all_forced(sc, aphy); Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com