From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932271AbbGJN0V (ORCPT ); Fri, 10 Jul 2015 09:26:21 -0400 Received: from demumfd002.nsn-inter.net ([93.183.12.31]:46300 "EHLO demumfd002.nsn-inter.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932069AbbGJN0M (ORCPT ); Fri, 10 Jul 2015 09:26:12 -0400 Subject: Re: [RFC PATCH] i2c: busses: i2c-omap: Increase timeout for i2c interrupt To: ext Vignesh R , Wolfram Sang , Felipe Balbi References: <1436504994-31137-1-git-send-email-vigneshr@ti.com> <559F8670.2060305@nokia.com> <20150710090909.GF1528@katana> <559FC5D7.3000108@ti.com> Cc: Tony Lindgren , linux-omap@vger.kernel.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org From: Alexander Sverdlin Message-ID: <559FC7E9.1060003@nokia.com> Date: Fri, 10 Jul 2015 15:26:01 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.0.1 MIME-Version: 1.0 In-Reply-To: <559FC5D7.3000108@ti.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-purgate-type: clean X-purgate-Ad: Categorized by eleven eXpurgate (R) http://www.eleven.de X-purgate: clean X-purgate: This mail is considered clean (visit http://www.eleven.de for further information) X-purgate-size: 840 X-purgate-ID: 151667::1436534762-000076F8-239ABBE9/0/0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi! On 10/07/15 15:17, ext Vignesh R wrote: >>> I would propose you to throw away spinlocks. Convert threaded IRQ to >>> >> just one hardirq handler. And continue debugging. You will reduce the >>> >> load of the system with the above measures, maybe it will not happen >>> >> any more, maybe you'll figure out that problem is somewhere else. >> > >> > Or this. > I am not convinced with moving entire code at hardirq context. I believe > its better to keep hardirq as small as possible. How deep is the controller's FIFO? 1 byte? 2 bytes? Other drivers can perfectly fill next byte in hardirq handler. If you need to do 10 opcodes more in hardirq handler, it's much better for the whole system than to trigger scheduler and thread and and and just because of these 10 opcodes. -- Best regards, Alexander Sverdlin.