From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail2.candelatech.com ([208.74.158.173]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Zvxg5-0002s5-UX for ath10k@lists.infradead.org; Tue, 10 Nov 2015 01:24:54 +0000 Received: from [192.168.100.149] (firewall.candelatech.com [50.251.239.81]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by mail2.candelatech.com (Postfix) with ESMTPSA id 8639E40AF76 for ; Mon, 9 Nov 2015 17:24:32 -0800 (PST) From: Ben Greear Subject: Setting 3x3 NIC to 2x2 Message-ID: <56414750.8080706@candelatech.com> Date: Mon, 9 Nov 2015 17:24:32 -0800 MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "ath10k" Errors-To: ath10k-bounces+kvalo=adurom.com@lists.infradead.org To: ath10k Hello! For this case: 2 PCs, one 3x3 peregrine ath10k NIC in each. Once acting as AP, the other as a station. Testing UDP upload performance. Someone reported a problem where they thought they had a 2x2 ath10k NIC but in reality it was 3x3. They had only the first two antenna connected. Using stock Fedora 21 kernel and firmware-4.bin, performance was horrible..around 8-10Mbps UDP throughput at best. This was on 2.4 band, so VHT is disabled. I think the first issue is that performance is so bad if you are missing a single antenna. (In my lab, a similar setup with 3 antenna connected was giving 120+Mbps throughput). The second problem I saw only on non-stock firmware & driver, so of course problem could be related to that: If I start up system in 3x3 mode, and then try to change to 2x2 by setting the tx-antenna mask with iw, then it *appears* that everything is passed down to the firmware properly, but performance is horrible (5-10Mbps). Forcing rate-ctrl to use a higher fixed speed makes things worse, so it's not just rate-ctrl messing up. Restarting all network devices on that radio, which causes a soft NIC reboot, does not fix the problem. (I reset both AP and STA machines radios multiple times) But, if I do a full reboot, then the system comes up happy and will negotiate up to 300Mbps nominal rate (ie, full 2x2 capabilities). I suspect there may be bugs in setting up registers down in the firmware, but I have not taken a close look at it at. As always, I'm curious if others have seen similar problems (or, tried this and NOT seen such problems.) Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com _______________________________________________ ath10k mailing list ath10k@lists.infradead.org http://lists.infradead.org/mailman/listinfo/ath10k