Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751631AbaGGT3g (ORCPT ); Mon, 7 Jul 2014 15:29:36 -0400 Received: from plane.gmane.org ([80.91.229.3]:45127 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750979AbaGGT3f (ORCPT ); Mon, 7 Jul 2014 15:29:35 -0400 X-Injected-Via-Gmane: http://gmane.org/ To: linux-kernel@vger.kernel.org From: Manuel Reimer Subject: Re: 3.15.4 runs *significantly* slower than 3.15.3 on iMX233 CPU Date: Mon, 07 Jul 2014 21:29:21 +0200 Lines: 41 Message-ID: References: <20140707191430.GA23004@roeck-us.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: p5dd560e1.dip0.t-ipconnect.de User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 In-Reply-To: <20140707191430.GA23004@roeck-us.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/07/2014 09:14 PM, Guenter Roeck wrote: > Are you sure this did not just happen when you booted the new kernel > for the first time ? I have seen similar behavior with some distributions. I did some more tries and found out that I had disabled some of my patches until I reached 3.15.4 (latest version) where I decided to do needed modifications to get my patches back in. I tracked the problem down to the following patch: diff --git a/arch/arm/boot/dts/imx23-olinuxino.dts b/arch/arm/boot/dts/imx23-olinuxino.dts index d107c4a..993da2e 100644 --- a/arch/arm/boot/dts/imx23-olinuxino.dts +++ b/arch/arm/boot/dts/imx23-olinuxino.dts @@ -64,7 +64,14 @@ compatible = "fsl,imx23-spi"; pinctrl-names = "default"; pinctrl-0 = <&spi2_pins_a>; + clock-frequency = <1000000>; status = "okay"; + + spidev0: spidev@0 { + compatible = "spidev"; + spi-max-frequency = <1000000>; + reg = <0>; + }; }; }; I need this to add spidev support. But I don't understand why this change kills performance? Maybe the "high" value in "clock-frequency"? Can someone give me some information on how to fix this? Thank you very much in advance. Greetings, Manuel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/