Return-path: Received: from mail-qw0-f46.google.com ([209.85.216.46]:52363 "EHLO mail-qw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756044Ab0KXWlm convert rfc822-to-8bit (ORCPT ); Wed, 24 Nov 2010 17:41:42 -0500 Received: by qwb7 with SMTP id 7so259002qwb.19 for ; Wed, 24 Nov 2010 14:41:41 -0800 (PST) MIME-Version: 1.0 In-Reply-To: References: <20101123191533.GP4303@makis.mantri> From: Jonathan Guerin Date: Thu, 25 Nov 2010 08:41:25 +1000 Message-ID: Subject: Re: [ath5k-devel] [PATCH 16/30] ath5k: Set all IFS intervals, not just slot time To: Nick Kossifidis Cc: ath5k-devel@lists.ath5k.org, linux-wireless@vger.kernel.org, linville@tuxdriver.com, me@bobcopeland.com, mcgrof@gmail.com, jirislaby@gmail.com, nbd@openwrt.org, br1@einfach.org Content-Type: text/plain; charset=windows-1252 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Wed, Nov 24, 2010 at 10:55 PM, Nick Kossifidis wrote: > 2010/11/24 Jonathan Guerin : >> >>> diff --git a/drivers/net/wireless/ath/ath5k/pcu.c b/drivers/net/wireless/ath/ath5k/pcu.c >>> index e691378..4556f29 100644 >>> --- a/drivers/net/wireless/ath/ath5k/pcu.c >>> +++ b/drivers/net/wireless/ath/ath5k/pcu.c >>> @@ -763,7 +763,7 @@ ath5k_hw_check_beacon_timers(struct ath5k_hw *ah, int intval) >>> ?* @ah: The &struct ath5k_hw >>> ?* @coverage_class: IEEE 802.11 coverage class number >>> ?* >>> - * Sets slot time, ACK timeout and CTS timeout for given coverage class. >>> + * Sets IFS intervals and ACK/CTS timeouts for given coverage class. >>> ?*/ >>> ?void ath5k_hw_set_coverage_class(struct ath5k_hw *ah, u8 coverage_class) >>> ?{ >>> @@ -772,7 +772,7 @@ void ath5k_hw_set_coverage_class(struct ath5k_hw *ah, u8 coverage_class) >>> ? ? ? ?int ack_timeout = ath5k_hw_get_default_sifs(ah) + slot_time; >> >> This is not quite right: >> >> According to the 802.11-2007 spec document, the ACKTimeout value is >> (Section 9.2.8 ACK procedure): >> ACKTimeout = aSIFSTime + aSlotTime + aPHY-RX-START-Delay >> >> From Table 17-15?OFDM PHY characteristics, the values are: >> aSIFSTime = 16 >> aSlotTime = 9 >> aPHY-RX-START-Delay = 25 >> >> Therefore, ACKTimeout = 50 >> >> Ignoring my uniformed comments from before, this is the only thing I >> can see that's wrong. >> >> Cheers, >> >> Jonathan > > Hmm I didn't mess with set_coverage_class so i didn't look up for ack > timeout. That phy-rx-start-delay is standard value or hw specific ? > Also does it change with clockrate (bwmodes) ? We already have a phy > activation -> rx start delay (check patch 25). It's 10.000 on RF5111 > and 2.000 on RF5112 and later, if we divide by A clock it's 250 on > RF5111 and 50 on RF5112 and later. Do you think it's related ? The phy-rx-start-delay is set in the standard. I'll find you the relevant pages soon. I'll look up the others tomorrow. I'm feeling pretty sick today, so not sure if I'll get a chance. Cheers, Jonathan > > -- > GPG ID: 0xD21DB2DB > As you read this post global entropy rises. Have Fun ;-) > Nick >