From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from nz-out-0506.google.com ([64.233.162.235]:11440 "EHLO nz-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753658AbXKBVZj (ORCPT ); Fri, 2 Nov 2007 17:25:39 -0400 Received: by nz-out-0506.google.com with SMTP id s18so756446nze for ; Fri, 02 Nov 2007 14:25:38 -0700 (PDT) Message-ID: <40f31dec0711021425y4e4bee5bi1c63ea165e6ed6a7@mail.gmail.com> (sfid-20071102_212544_903819_6787A7CC) Date: Fri, 2 Nov 2007 23:25:37 +0200 From: "Nick Kossifidis" To: "Luis R. Rodriguez" Subject: Re: [PATCH] ath5k: Set ACK to user lower bit rates Cc: "John Linville" , linux-wireless@vger.kernel.org, "Jiri Slaby" , ath5k-devel@lists.ath5k.org In-Reply-To: <40f31dec0711021413u397f9cb9r99ef8b9ca51ea01c@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 References: <20071102204638.GA3227@pogo> <40f31dec0711021413u397f9cb9r99ef8b9ca51ea01c@mail.gmail.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: 2007/11/2, Nick Kossifidis : > 2007/11/2, Luis R. Rodriguez : > > Sorry, forgot this last hunk in my patch series... This applies on top > > of my series. > > > > This sets the ACK bitrate to the lower rates. Without this I get > > about 70% packet loss when using the 11M rate. Not sure exactly what rates > > this is setting the HW to send the ACKs in but it sure does help. > > > > 6Mbits for OFDM (have checked it out with various sniffers), if not > set i usualy get 24Mbits for acks when transmiting on 54Mbit. > > Haven't checked it for CCK but i guess it's 1 or 2 Mbits, have a look > at my comments inside reg.h... > > #define AR5K_STA_ID1_ACKCTS_6MB 0x01000000 /* Use 6Mbit/s > for ACK/CTS (?) */ > #define AR5K_STA_ID1_BASE_RATE_11B 0x02000000 /* Use 11b > base rate (for ACK/CTS ?) [5211+] */ > Also note that setting these bits is safe and cause a more stable behaviour. If these bits are not set then control_rate is being used (check out rate tables -remember these tables are hardcoded in hal, that's why they have put control_rate there, to let us know what rate is being used for ack/cts frames by hw-). Here it is... (transmision rate) -> (ack/cts rate) OFDM 6 - 12 -> 6 12 - 24 -> 12 24 - 54 -> 24 CCK 1 - 2 -> 1 2 - 11 -> 2 So it still doesn't make sense that you had 70% loss, i mean any rate between 2 and 11Mbits would cause the same ack rate (2Mbits), even if you didn't set that bit. -- GPG ID: 0xD21DB2DB As you read this post global entropy rises. Have Fun ;-) Nick