From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760306AbZKZM44 (ORCPT ); Thu, 26 Nov 2009 07:56:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757301AbZKZM4z (ORCPT ); Thu, 26 Nov 2009 07:56:55 -0500 Received: from opensource.wolfsonmicro.com ([80.75.67.52]:56759 "EHLO opensource2.wolfsonmicro.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757287AbZKZM4z (ORCPT ); Thu, 26 Nov 2009 07:56:55 -0500 Date: Thu, 26 Nov 2009 12:56:59 +0000 From: Mark Brown To: Andy Walls Cc: Tejun Heo , Peter Ujfalusi , Stephen Rothwell , "linux-next@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Takashi Iwai Subject: Re: linux-next: workqueues tree build failure Message-ID: <20091126125659.GD1037@rakim.wolfsonmicro.main> References: <20091126190050.3f9d7fef.sfr@canb.auug.org.au> <4B0E3677.6000603@kernel.org> <200911261016.58810.peter.ujfalusi@nokia.com> <4B0E467A.8080201@kernel.org> <1259239225.3062.16.camel@palomino.walls.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1259239225.3062.16.camel@palomino.walls.org> X-Cookie: Crazee Edeee, his prices are INSANE!!! User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 26, 2009 at 07:40:25AM -0500, Andy Walls wrote: > I'm not sure doing things like I2C transactions in the in the top half > of the IRQ handler is generally viable. On shared IRQ lines, wouldn't > this hold off the interrupt for another device for too long? You're going to need to do I2C I/O to acknowledge and deassert the interrupt on most of these devices so if someone's shared the IRQ line with something that's too latency sensitive the hardware is broken anyway. > Workhandlers for deferring work are a nice way to avoid such bad system > level interactions. In order to cope with the fact that the IRQ can't be deasserted without talking to the device it will almost always be masked while waiting for the deferred work.