Return-path: Received: from mail-fx0-f46.google.com ([209.85.161.46]:54692 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752260Ab1AVWww convert rfc822-to-8bit (ORCPT ); Sat, 22 Jan 2011 17:52:52 -0500 Received: by fxm20 with SMTP id 20so2929658fxm.19 for ; Sat, 22 Jan 2011 14:52:51 -0800 (PST) From: Christian Lamparter To: Richard =?iso-8859-15?q?Sch=FCtz?= Subject: Re: ath9k prevents CPU from entering C4 state (kernel 2.6.37 regression) Date: Sat, 22 Jan 2011 23:52:42 +0100 Cc: linux-wireless@vger.kernel.org References: <4D3B4057.5000206@t-online.de> In-Reply-To: <4D3B4057.5000206@t-online.de> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Message-Id: <201101222352.42913.chunkeey@googlemail.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Saturday 22 January 2011 21:38:47 Richard Sch?tz wrote: > I noticed that from kernel 2.6.37 on (i've tested 2.6.38-rc2, too) ath9k > prevents my CPU (Intel Atom N450) from entering the C4 power state. It > only goes down to C2 (there's no C3) instead. In 2.6.36(.3) everything > is still fine. The CPU will only go down to C4 with 2.6.37 when the > wireless interface is brought down. "ath9k: Fix a DMA latency issue for Intel Pinetrail platforms." http://www.spinics.net/lists/linux-wireless/msg58264.html the pm_qos value will be configurable with 2.6.38: "ath9k: Make PM-QOS value as user configurable" http://www.spinics.net/lists/linux-wireless/msg61259.html "This will help our customers to configure the pm-qos value according to the effect in throughput due to the DMA latency problem which was observed in Intel Pinetrail platforms."