Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756213AbZGUVtv (ORCPT ); Tue, 21 Jul 2009 17:49:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755529AbZGUVtu (ORCPT ); Tue, 21 Jul 2009 17:49:50 -0400 Received: from www.tglx.de ([62.245.132.106]:38196 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755517AbZGUVtt (ORCPT ); Tue, 21 Jul 2009 17:49:49 -0400 Date: Tue, 21 Jul 2009 23:48:44 +0200 (CEST) From: Thomas Gleixner To: Dmitry Torokhov cc: Mark Brown , Trilok Soni , Pavel Machek , Arve Hj?nnev?g , kernel list , Brian Swetland , linux-input@vger.kernel.org, Andrew Morton , linux-i2c@vger.kernel.org, Joonyoung Shim , m.szyprowski@samsung.com, t.fujak@samsung.com, kyungmin.park@samsung.com, David Brownell , Peter Zijlstra Subject: Re: Threaded interrupts for synaptic touchscreen in HTC dream In-Reply-To: <20090721205841.GA7755@dtor-d630.eng.vmware.com> Message-ID: References: <5d5443650907140320w334864f4uc1ee13ed32fdb874@mail.gmail.com> <20090715133627.GA2538@elf.ucw.cz> <5d5443650907151033w36008b71pe4b32bcea9489b75@mail.gmail.com> <20090721105924.GK4133@elf.ucw.cz> <20090721113642.GC13286@sirena.org.uk> <5d5443650907210518i6ee4df1evdc04d9ae9453707c@mail.gmail.com> <5d5443650907210530x4aaa03d6gd47ef5f79a3ef8a4@mail.gmail.com> <20090721124933.GA5668@rakim.wolfsonmicro.main> <20090721160436.GD4352@dtor-d630.eng.vmware.com> <20090721205841.GA7755@dtor-d630.eng.vmware.com> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2210 Lines: 57 On Tue, 21 Jul 2009, Dmitry Torokhov wrote: > On Tue, Jul 21, 2009 at 10:30:26PM +0200, Thomas Gleixner wrote: > > On Tue, 21 Jul 2009, Dmitry Torokhov wrote: > > > > > On Tue, Jul 21, 2009 at 01:49:33PM +0100, Mark Brown wrote: > > > > On Tue, Jul 21, 2009 at 06:00:07PM +0530, Trilok Soni wrote: > > > > > > > > > Hopefully, this thread can give all details about threaded irq discussion. > > > > > > > > > http://lkml.org/lkml/2009/2/27/255 > > > > > > > > Yes, I'm aware of that - I read it at the time. It seemed to peter out > > > > without any satisfactory solution, unfortunately. There's two separate > > > > issues here: > > > > > > > > - Ordinary devices on interrupt driven or slow buses like I2C. These > > > > need something along the lines of request_threaded_irq() that's allows > > > > them to schedule the main IRQ handler outside hardirq context so > > > > that they can interact with the device. They need to do something in > > > > hardirq context to disable the interrupt if it's level triggered but > > > > most of the time the only option they've got is to disable the IRQ > > > > and reenable it when the worker thread is done. This is the issue > > > > here. > > > > There is already a sane solution to the problem: > > > > See http://lkml.org/lkml/2009/7/17/174 > > > > > > My immediate thought when I noticed this was that we should probably > > > > fix request_threaded_irq() so that it's useful for them; I'd been > > > > intending to do some digging and try to understand why it is > > > > currently implemented as it is. > > > > What's to fix there ? > > > > duisable_irq_nosync() in the hard interrupt handler stops the thread > handler from running. Unfortunately there are devices where it is the > only thing we can do in the hard interrupt. Again: There is already a sane solution to the problem: See http://lkml.org/lkml/2009/7/17/174 Thanks, tglx -- 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/