From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751561AbeD1Tb2 (ORCPT ); Sat, 28 Apr 2018 15:31:28 -0400 Received: from mail-pf0-f175.google.com ([209.85.192.175]:39831 "EHLO mail-pf0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751351AbeD1TbM (ORCPT ); Sat, 28 Apr 2018 15:31:12 -0400 X-Google-Smtp-Source: AB8JxZp5JciMlSaCUz6QHrGwtOqlWnR9V2SBqnIz4bdAsChwvBgi7Qk1iJtQLt9HEZNGUbhsDTO2aA== Date: Sat, 28 Apr 2018 12:31:11 -0700 From: Moritz Fischer To: Vinod Koul Cc: Lars-Peter Clausen , Moritz Fischer , Linux Kernel Mailing List , dmaengine@vger.kernel.org, dan.j.williams@intel.com Subject: Re: [PATCH v2] dmaengine: axi-dmac: Request IRQ with IRQF_SHARED Message-ID: <20180428193111.drxleoqiwu723lwr@derp-derp.lan> References: <20180426174000.12008-1-mdf@kernel.org> <20180427051115.GX6014@localhost> <748ffc14-de12-c11e-eb12-65c599fe5f4e@metafoo.de> <20180427070830.GC6014@localhost> <716956a2-a4f4-9cbd-8761-8db477f1dfc0@metafoo.de> <20180428051043.GG6014@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180428051043.GG6014@localhost> User-Agent: NeoMutt/20171215 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Apr 28, 2018 at 10:40:43AM +0530, Vinod Koul wrote: > On Fri, Apr 27, 2018 at 05:18:29PM +0200, Lars-Peter Clausen wrote: > > On 04/27/2018 05:15 PM, Moritz Fischer wrote: > > > Hi Vinod, > > > > > > On Fri, Apr 27, 2018 at 12:08 AM, Vinod Koul wrote: > > >> On Fri, Apr 27, 2018 at 08:53:39AM +0200, Lars-Peter Clausen wrote: > > >>> On 04/27/2018 07:11 AM, Vinod Koul wrote: > > >>>> On Thu, Apr 26, 2018 at 10:40:00AM -0700, Moritz Fischer wrote: > > >>>>> Request IRQ with IRQF_SHARED flag. This works since the interrupt > > >>>>> handler already checks if there is an actual IRQ pending and returns > > >>>>> IRQ_NONE otherwise. > > >>>> > > >>>> hmmm what are we trying to fix here? Is your device on a shared line or not? > > >>> > > >>> IRQF_SHARED does not mean that the IRQ is on a shared line. It means that > > >>> the driver can handle it if the IRQ is on a shared line. Since the driver > > >>> can handle it setting the flag is a good idea since this enables usecases > > >>> where the line is shared. > > >> > > >> Yes that is correct indeed, but what is the motivation for the change. > > >> > > >> If you never expect this to be in shared environment why to do this? > > >> Sorry but "it works" is not a good enough reason for this change, to enable > > >> usecases where the line is shared is a good reason :) > > > > > > Remember, this is an FPGA soft core. I happen to have a design [1] where it > > > is hooked up with multiple of them on one IRQ line, so to make this work, > > > I need this change. > > > > I think what Vinod is asking for is a change to the commit message saying > > that "this change enables the driver to be used with devices where the > > interrupt line is shared". > > Correct, changelog need to reflect why a change was made, down the line > people need to know the reasons, sometimes it might be even you.. Ok, communication is hard :) Will resubmit with fixed commit message, Thanks for your feedback, Moritz